JP4887082B2 - Friction reduction sheet unit, caisson housing and press-fitting caisson method using the caisson housing - Google Patents

Description

  The present invention relates to a friction reducing sheet in which a long friction reducing sheet provided with a friction reducing material layer on at least one surface thereof is wound up in a roll shape, and the rolled friction reducing sheet is accommodated in a box so as to be fed out. It is about the unit.

  Further, the present invention is configured to press-sink a caisson housing having a caisson blade with an inner blade shape at the tip into the ground for each predetermined stroke, and to discharge the mud within the caisson housing to the outside while excavating it. The present invention relates to a caisson housing used in a press-in caisson method for constructing a caisson shaft having a predetermined depth by installing a subsequent housing above the caisson housing, and a press-in caisson method using the caisson housing.

  For example, when building a bridge pier in the ground or on the seabed, or when excavating a shaft for starting or reaching in shield construction, a structure with an inner blade-like edge formed at the tip, which has been conventionally called “caisson” A frame is used, and the “press-in caisson method” using this “caisson” is being implemented. The "press-in caisson method" is an "open type press-in caisson method" in which caisson is press-fitted into the ground using the weight of caisson, etc. “Press-fit caisson method”, “push-in caisson method (pneumatic caisson method combined with press-fitting)” that presses and sinks caisson into the ground using air, or a combination of these There is a press-in caisson method.

  Of these, if the “hydraulic press-fitting caisson method” is taken as an example, a rod-like support member called a “press-fit reaction force anchor” that has been driven in advance outside the excavation site is supported by a hydraulic jack, etc. Is hydraulically driven to cause the "caisson" to be pressed and settled by a predetermined stroke in the ground or on the sea floor. Then, the ground inside the caisson was excavated and discharged using a clamshell bucket or the like. In addition, by placing the succeeding chassis precast on the caisson that has been pressed and settled for a predetermined stroke and repeating the caisson press-in, mud excavation and discharge, and the subsequent expansion of the succeeding chassis, the predetermined depth is finally reached. A caisson shaft was built.

  A problem in such a press-in caisson method is the frictional resistance between the ground and the caisson body, or between the ground and the following body, which occurs when the caisson body is pressed and settled. The following Patent Document 1 discloses a construction method for the purpose of reducing the frictional resistance mainly used when placing a steel sheet pile or the like. That is, it is a construction method in which a friction-reducing resin material is applied to the surface of a sinking body that is in sliding contact with the ground. However, if the friction reducing resin material is simply thinly applied to the surface of the sedimentary body, it gradually peels off as the sedimentary body is press-fitted and settled, so that the desired friction reduction effect may not be exhibited. . In addition, the friction-reducing resin material stays in the ground permanently or for a long time together with the sedimentary body, so that organic solvents, etc. in the friction-reducing resin material may permeate into the ground and adversely affect the surrounding environment. Is also a concern.

  Patent Document 2 below discloses a method for reducing frictional resistance used in caisson press-fitting and sedimentation. That is, the feeding tip of the friction reducing metal sheet having a small friction coefficient is attached in close contact with the outer peripheral surface of the caisson that is in sliding contact with the ground, and the friction reducing metal sheet is gradually pulled down into the ground as the caisson press-fits. It is a construction method. However, if only such a friction reducing metal sheet is used, the sliding contact resistance between the ground and the caisson can be avoided, but the sliding contact resistance between the friction reducing metal sheet and the caisson cannot be avoided, so a sufficient friction reducing action cannot always be obtained. There is a case. In such a case, incidental and auxiliary measures have been taken to reduce the frictional resistance by sending compressed air between the ground and the friction reducing metal sheet.

JP 2003-55982 A Japanese Patent No. 788314

  The object of the present invention is to provide a friction reducing sheet unit, caisson capable of obtaining an effective and stable friction reducing action, for example, at the time of press-fitting and sinking a caisson housing, and reducing material, construction cost, construction labor, and construction period. An object of the present invention is to provide a casing and a press-fitting caisson method using the caisson casing.

  In order to solve the above problems, a first aspect of the present invention is a friction reducing sheet wound up in a roll shape, and a friction reducing material layer is provided on at least one side of the sheet in the wound state. A friction-reducing sheet unit in which a roll-shaped friction reducing sheet is accommodated in a box so that it can be fed out and is filled with a granular water-stopping agent that swells when it comes into contact with water and expresses water-stopping properties. It is.

  According to the first aspect of the present invention, the friction reducing sheet has the friction reducing material layer provided on the surface thereof. Therefore, for example, the friction reducing sheet unit is attached to the outer peripheral surface of the caisson that is in sliding contact with the ground, and the roll-like friction reducing sheet is unwound as the caisson is pressed and settled, and the friction reducing sheet is gradually fed into the ground. By using this, the sliding resistance between the ground and the caisson can be completely avoided, and the sliding resistance between the friction reducing sheet and the caisson can be greatly reduced by the friction reducing material layer.

Further, the box in which the roll-shaped friction reducing sheet is accommodated is filled with a granular water-stopping agent that can swell when it comes into contact with water to develop a water-stopping property. Therefore, when water enters from the feeding opening of the friction reducing sheet, it simultaneously contacts and reacts with the granular water-stopping agent in the vicinity of the feeding opening to swell, thereby sealing the feeding opening and the outside. Blocking, that is, water-stopping is developed, and water intrusion into the box is prevented.
When the friction reducing sheet is drawn out from the feeding opening, the sealing state due to the swelling breaks and water enters from there, but immediately reacts with the unreacted water-stopping agent and newly swells, and the feeding opening is sealed again. Stopped.

  If the water-stopper is not filled in the box, water will easily enter the box. Then, the friction reducing material layer of the rolled friction reducing sheet comes into contact with water. In this case, the friction reducing material layer is deteriorated by contact with water, depending on the type of the material. May not be able to be exhibited reliably.

According to the present invention, the water-stopping agent filled in the box prevents water from entering the box, so that there is no possibility that the friction reducing material layer is deteriorated by water, and the friction reducing sheet is The friction reducing function can be surely exhibited at the time when the friction reducing function should be exerted by being drawn out of the box.

According to a second aspect of the present invention, in the friction-reducing sheet unit of the first aspect, the friction-reducing material layer of the friction-reducing sheet swells when contacted with water, and a material that exhibits a friction-reducing function by this swelling. It is characterized by being formed.

In the present invention, the effect obtained particularly when using the friction reducing sheet having the friction reducing material layer having such characteristics is remarkable. In other words, this type of friction reducing material layer has an excellent effect of reducing sliding friction with the caisson, but the caisson is swollen in contact with the water in the ground after the friction reducing sheet is drawn out of the box. This is an effect obtained when it is in sliding contact. When the friction reducing sheet comes into contact with water in the box before being fed out of the box, it reacts and swells there, and the friction reducing material layer peels off when the sheet is drawn out from the box, and exhibits the original friction reducing function. There is a possibility that the function cannot be exhibited at a proper time. According to the present invention, as described above, this possibility can be reliably reduced.

According to a third aspect of the present invention, in the friction-reducing sheet unit according to the first aspect or the second aspect, the box is provided with a pressure-proof reinforcing portion.

In the ground, soil pressure is received from the outside of the box, but water does not enter the box by the water-stopping agent, so the pressure in the box becomes smaller than the external soil water pressure and the pressure balance is lost. For this reason, the box may be crushed by earth water pressure.
According to the present invention, since the box is provided with the pressure-proof strengthening portion, the risk can be reduced. As this pressure-proof strengthening part, it is preferable that the reinforcing rib is integrally formed on the inner wall surface of the box because it can be easily made.

  According to a fourth aspect of the present invention, in the friction reducing sheet unit according to any one of the first to third aspects, the box is formed in a double tube structure of an inner box and an outer box, and the roll friction The reduction sheet is accommodated in the inner box, and the water-stopping agent is filled in a space between the inner box and the outer box.

  The friction reducing sheet is wound up in a roll shape and accommodated in the box. Therefore, when the friction reducing sheet is fed out for use, the size of the roll is reduced. As a result, the water-stopping agent in the box has a problem that the upper surface of the water-stopping agent is drastically lowered as the roll becomes smaller, and water easily enters the box from the feed opening.

  According to the present invention, the box is formed in a double tube structure of an inner box and an outer box, the roll-shaped friction reducing sheet is accommodated in the inner box, and the waterstop agent is provided between the inner box and the outer box. The space between is filled. Therefore, even if the roll of the friction reducing sheet is reduced in use, the friction reducing sheet is accommodated in the inner box, while the waterstop agent is a space between the inner box and the outer box. Because it is filled in, it is not affected. Accordingly, the water-stopping agent can be present in the box without being affected by the roll size of the roll-like friction reducing sheet, so that the feeding port can be reliably sealed.

  According to a fifth aspect of the present invention, in the friction-reducing sheet unit according to any one of the first to fourth aspects, the water-stopping agent is composed of different types of multilayers and is laminated on the feeding opening side of the box. The water-stopping agent is characterized in that it is made of a material having a larger amount of swelling due to contact with water than the water-stopping agent laminated on the back side. Here, the multilayer is not limited to two layers. Three or more layers may be used.

  Water rarely penetrates into the back of the box. According to the present invention, it is possible to reduce the cost of the water-stopping agent to be used by using a material that has less swelling due to contact with water than the feed opening side on the back side in the box.

According to a sixth aspect of the present invention, a caisson enclosure having an inner blade-shaped caisson blade tip formed at the tip is pressed and settled into the ground for each predetermined stroke, and the mud within the caisson enclosure is excavated and discharged to the outside. A caisson housing used in a press-in caisson method for constructing a caisson shaft having a predetermined depth by further adding a subsequent housing above the caisson housing, wherein the caisson housing includes a first aspect. To the fifth aspect, the friction reducing sheet unit is arranged in a state of being substantially connected over a plurality of locations along the outer peripheral surface of the caisson housing, and along with the press-fitting and sinking of the caisson housing. The friction reducing sheet is configured to be gradually drawn out.
According to the present invention, it is possible to obtain the same effect as that of any of the first to fifth aspects.

According to a seventh aspect of the present invention, a caisson enclosure having an inner blade-shaped caisson blade tip formed at the tip is pressed and settled into the ground for each predetermined stroke, and the mud within the caisson enclosure is excavated and discharged to the outside. In addition, it is a press-in caisson construction method for constructing a caisson shaft having a predetermined depth by installing a subsequent case above the caisson case, wherein the caisson case of the sixth aspect is used as the caisson case, The friction-reducing sheet is gradually drawn downward by press-fitting the caisson casing while holding the leading end of the sheet, and the caisson casing or the succeeding casing added to the caisson casing is the friction-reducing sheet. It is characterized by being in sliding contact with the friction reducing sheet via a material layer.
According to the present invention, it is possible to obtain the same effect as that of any of the first to fifth aspects.

  According to the present invention, the box in which the roll-shaped friction reducing sheet is accommodated is filled with a granular water-stopping agent that swells when brought into contact with water and can exhibit water-stopping properties. Therefore, when water enters from the feeding opening of the friction reducing sheet, it simultaneously contacts and reacts with the granular water-stopping agent in the vicinity of the feeding opening to swell, thereby sealing the feeding opening and the outside. Blocking, that is, water-stopping is developed, and water intrusion into the box is prevented. As described above, since the ingress of water into the box is prevented, there is no possibility that the friction reducing material layer is deteriorated by water, and the friction reducing sheet should be drawn out of the box to exhibit the friction reducing function. Thus, the friction reducing function can be surely exhibited.

  Hereinafter, the caisson housing and the press-fitting caisson method using the caisson housing according to the present invention will be described with reference to the following Example 1 and Example 2. First, an outline of the press-fitting caisson method according to the present invention and mechanical equipment necessary for executing the press-fitting caisson method will be described.

  FIG. 1 is a side sectional view showing an example of mechanical equipment used to execute a press-fitting caisson method using the caisson housing of the present invention. FIG. 2 is a mechanical equipment used to execute a press-fitting caisson method using the caisson housing of the present invention. It is a top view which shows an example.

  There are three types of press-in caisson methods as described above. Here, a press-in caisson method combining an open-type press-in caisson method and a hydraulic press-in caisson method will be described. In this press-fitting caisson method, a caisson casing 1 having a caisson cutting edge 2 inclined at the tip is formed at the tip, a pressurizing girder 9 utilizing its own weight as a press-fitting settling means of the caisson casing 1, and a press-fitting device The hydraulic jack 13 is used.

  In this press-fitting caisson method, the caisson enclosure 1 is pressed and settled by a predetermined stroke into the ground G in the ground (including the seabed and under the river), and further mud soil (including earth and sand) R inside the caisson enclosure 1 is excavated. It discharges outside the caisson housing 1 (for example, on the ground). Then, as an example precast above the caisson housing 1, a caisson shaft 5 having a predetermined depth is constructed by adding a subsequent concrete housing 4 made of concrete. The press-fitting caisson method is used when a shaft for constructing a pier, a shaft for starting or reaching when a shield tunnel 15 is constructed underground, or the like is constructed.

  And in order to implement such a press-fitting caisson method, the formwork 10 for precasting the mechanical equipment 6 and the subsequent frame 4 as shown in the figure, the scaffolding 8 for work, etc. are used (FIG. 5). . As the mechanical equipment 6, a crane 7 that is installed and fixed on the ground around the site where the caisson shaft 5 is constructed, and a suspension that is attached to the lower end of a suspension wire that is suspended from the tip of a suspension arm of the crane 7. A hook 16 (FIG. 5) or a grab bucket 14 exists. The crane 7 shown in the figure is a crawler type crane that can move in any direction. However, the crane 7 is a fixed crane that is installed in a completely fixed state on the ground or a large crane that is supported by a larger portal machine frame. Of course, it is also possible to adopt.

  The hydraulic jack 13 is placed in advance in the ground where the caisson shaft 5 is constructed, and the caisson housing 1 is placed in the ground by a cooperative action with the earth anchor 17 which is a bar-like support member raised upward. It is a device for press-fitting into the ground G. In the illustrated mechanical equipment 6, twelve earth anchors 17 are provided as shown in FIG. 2, and one of the pressure girders 9 and two hydraulic jacks are used by using two of the earth anchors 17. 13 constitutes a set of press-fit sedimentation means. The hydraulic jack 13 used in the present invention is a center hole jack in which a hole for receiving the gripper rod is formed at the center. When the earth anchor 17 is clamped by the anchor chuck 18 provided at the lower end of the gripper rod, the hydraulic jack 13 is hydraulic. The jack 13 and the ground anchor 17 are connected, and when the anchor chuck 18 is released, the hydraulic jack 13 and the ground anchor 17 are disconnected.

  Further, the grab bucket 14 is constituted by a pair of bucket elements that are pivotably opened and closed and provided with comb-like claws for excavating the ground G at the tip. Can be captured and drained of the captured mud R. The hanging hook 16 is a hanging tool used for hanging, moving, and installing the caisson casing 1, the succeeding casing 4, or the piece 19 (FIG. 8) that is an element of the succeeding casing 4. is there.

[Example 1]
Next, the caisson housing 1 of the present invention constructed using such mechanical equipment 6, the press-in caisson method of the present invention using the caisson housing 1, and the friction reducing sheet unit 29 according to the present invention will be described with reference to FIG. The first embodiment shown in FIG. 12 will be described as an example.
FIG. 3 is a side sectional view showing an example of the caisson casing of the present invention, and FIG. 4 is a transverse sectional view (a) showing an example of the caisson casing of the present invention, and a partially enlarged view (b) thereof. FIG. 5 is a side cross-sectional view of the first half part (a) to (d) showing an example of the press-fitting caisson method of the present invention for each process, and FIG. 6 is the second half part (a) to FIG. It is a sectional side view of (d). FIG. 7 is a side sectional view showing a stretched state of the friction reducing sheet that is fed out as the caisson housing is pressed and settled, and FIG. 8 is a perspective view showing various aspects of the caisson shaft constructed by the caisson housing of the present invention. Further, FIG. 9 is a perspective view showing stepwise the locked state of the winding base end portion of the friction reducing sheet, and FIG. 10 is an enlarged perspective view showing a part of the sheet unit arranged in an annular shape.
FIG. 11 is a side sectional view showing an example of a friction reducing sheet unit according to the present invention, and FIG. 12 is a horizontal sectional view thereof.

  The illustrated caisson housing 1 is used when a cylindrical caisson shaft 5 as shown in FIGS. 8B and 8D is constructed. Therefore, it has a cylindrical housing portion 20 (FIG. 4), and the caisson blade 2 having an inner blade shape is formed in an annular shape at the tip (end portion on the press-fitting and settling side) of the housing portion 20. (Figure 3). Further, on the outer peripheral portion at a position slightly above the center of the housing portion 20, a sheet installation portion 22 for installing a friction reduction sheet unit 29 containing a long friction reduction sheet 21 wound up in a roll shape. Is provided.

  The friction reducing sheet unit 29 has a roll-like friction in which a long friction reducing sheet 21 is wound in a roll shape, and a friction reducing material layer 30 is provided on at least the inner surface 31 of the wound sheet. The reduction sheet 21 is accommodated in the box 230 so as to be fed out.

  As shown in FIGS. 3 and 11, the box 230 is filled with a granular water-stopping agent 28 that swells when it comes into contact with water and develops water-stopping properties. And the said friction reduction material layer 30 of the said friction reduction sheet | seat 21 swells when it contacts with water, and is formed with the material which expresses a friction reduction function by this swelling.

Further, as shown in FIGS. 11 and 12, in this embodiment, the box 230 is formed in a double tube structure of the inner box 25 and the outer box 23, and the roll-like friction reducing sheet 21 is formed in the inner box 25. The water-stopping agent 28 is filled in the space between the inner box 25 and the outer box 23. The friction reducing sheet 21 is held in the inner box 25 so as to be freely rotatable. That is, between the left and right side plates facing the inner box 25, a winding shaft 24 that is a rotating shaft of the roll-shaped friction reducing metal sheet 21 in a wound state is stretched horizontally.
Further, the outer box 23 is integrally provided with a reinforcing rib 231 on its inner wall surface as a pressure strengthening portion.

  In this embodiment, a case where a metal (iron) sheet is used as the friction reducing sheet 21 (hereinafter referred to as “friction reducing metal sheet”) will be described, but it is needless to say that the present invention is not limited to this material.

  As shown in FIGS. 11 and 12, the outer box 23 is a substantially rectangular box-like member that is processed by appropriately bending a metal thin plate, and its outer end surface does not protrude from the outer peripheral surface of the housing portion 20. Is set to be almost flush with each other. The friction reducing sheet 21 passes through the slit 26 formed in a part of the inner box 25 and the feeding opening 27 formed in the outer box 23, so that the caisson casing 1 and the subsequent casing 4 installed thereabove. It is led to the ground along the outer peripheral surface. The feeding opening 27 is provided with a rubber plate 233 to enhance the sealing performance.

  The friction reducing sheet unit 29 including the outer box 23, the winding shaft 24, the inner box 25, the water blocking agent 28, the friction reducing metal sheet 21 and the rubber plate 233 is as shown in FIGS. A plurality of units are provided in a state of being substantially connected over a plurality of locations along the outer peripheral surface of the caisson housing 1.

  As the friction-reducing metal sheet 21 used in the present invention, a thin iron plate having a thickness of about 0.2 mm to 0.3 mm can be adopted, and the surface thereof is smoothly processed. The friction-reducing metal sheet 21 has a mechanical strength sufficient to withstand feeding and pulling out while being able to exhibit good coating property or pasting property of the reducing material layer 30.

  As described above, the friction reducing material layer 30 is provided on the inner surface 31 of the friction reducing metal sheet 21 by coating or pasting. In this embodiment, the friction reduction in the molten state is performed so that the thickness increases gradually from the winding base end side of the friction reduction metal sheet 21 toward the leading end side with respect to the inner surface 31 of the friction reduction metal sheet 21. The material of the material layer is applied to form a friction reducing material layer 30 in a laminated state composed of a plurality of layers. Here, as the raw material, the friction reducing material layer 30 is obtained by previously applying a friction reducing resin coating material, which contains the water absorbent resin (a), the hydrophilic binder resin (b), and the solvent (c) as essential components to the base material. Is formed.

  Further, as the water-stopping agent 28, specifically, the water-absorbing resin (a) is used.

Hereinafter, materials used for the water stop agent 28 and the friction reducing material layer 30 will be described.
The water-absorbent resin (a) used in the friction-reducing resin coating is a resin that swells by absorbing water and has a water absorption ratio of 3 times or more (25 ° C., 1 hour) with respect to its own weight. There is no particular limitation. However, the synthetic water-absorbent resin obtained by crosslinking a water-soluble hydrophilic compound (monomer and / or polymer) with a crosslinking agent, as exemplified below, has a swelling ratio and water capacity higher than those of natural water-swellable substances (gelatin, agar, etc.). These are preferable to natural water-swellable materials (gelatin, agar, etc.) because they have a good balance of dissolved content, water absorption rate, strength, etc. and can be easily adjusted.

  Specific examples of the water absorbent resin (a) as described above include, for example, a crosslinked poly (meth) acrylic acid, a crosslinked poly (meth) acrylate, and a poly (meth) acrylic acid having a sulfonic acid group. Cross-linked ester, cross-linked poly (meth) acrylate ester having polyoxyalkylene group, cross-linked poly (meth) acrylamide, cross-linked copolymer of (meth) acrylate and (meth) acrylamide, (meth) acrylic Copolymerized crosslinked product of hydroxyalkyl acid and (meth) acrylate, crosslinked polydioxolane, crosslinked polyethylene oxide, crosslinked polyvinylpyrrolidone, sulfonated polystyrene crosslinked product, crosslinked polyvinylpyridine, starch-poly (meth) acrylonitrile graft copolymer Saponification of coalescence, starch-poly (meth) acrylic acid (salt) graft cross-linking copolymer Coalescing, reaction products of polyvinyl alcohol and maleic acid (salt), cross-linked polyvinyl alcohol sulfonate, polyvinyl alcohol - acrylic acid graft copolymers, polyisobutylene maleic acid (salt) cross-linked polymer, and the like. These water-absorbing resins (a) may be used alone or in combination of two or more.

  In the present invention, it is preferable to use a salt-resistant water-absorbing resin as the water-absorbing resin (a). The reason why salt-resistant water-absorbent resins are preferred is that salt-resistant water-absorbent resins have a relatively high water absorption capacity of hard water containing polyvalent metals and are not significantly affected by the water quality in the soil when used in friction-reducing resin coatings. This is because the friction reducing effect can be exhibited.

  The salt-resistant water-absorbent resin in the present invention is not particularly limited as long as the water absorption ratio (25 ° C., 24 hours) in artificial seawater is 10 times or more. For example, the water-absorbent resin (a) exemplified above is used. Among them, those having a nonionic group and / or a sulfonic acid (salt) group are more preferred, and those having an amide group or a hydroxyalkyl group are more preferred. Examples of the salt-resistant water-absorbing resin as described above include, for example, a copolymer crosslinked product of (meth) acrylate and (meth) acrylamide, and a copolymer of hydroxyalkyl (meth) acrylate and (meth) acrylate. A crosslinked body etc. are mentioned. Further, those having a polyoxyalkylene group are particularly preferred. Examples of such a water absorbent resin (a) include a crosslinked copolymer of (meth) acrylate having a methoxypolyoxyalkylene group and (meth) acrylate.

  These salt-resistant water-absorbing resins can swell up to a certain magnification regardless of the nature of the water in the soil (soft water, hard water, etc.), and more reliably exhibit the friction reducing function. it can.

  Furthermore, the production method of the water-absorbent resin (a) used for the friction-reducing resin coating is not particularly limited. For example, a single amount containing a water-soluble ethylenically unsaturated monomer and, if necessary, a crosslinking agent. And a method of polymerizing body components. The water-absorbing resin (a) obtained by (co) polymerizing an ethylenically unsaturated monomer is excellent in water absorption with respect to water and is generally inexpensive. In addition, said crosslinking agent is not specifically limited.

  Specific examples of the ethylenically unsaturated monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, citraconic acid, vinyl sulfonic acid, and (meth) allyl sulfonic acid. 2- (meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, and alkali metal salts and ammonium salts of these monomers; N , N-dimethylaminoethyl (meth) acrylate and quaternized products thereof; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, diacetone (meth) acrylamide, N- Isopropyl (meth) acrylamide, (meth) acryloyl morpho (Meth) acrylamides such as ethylene, and derivatives of these monomers; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; polyethylene glycol mono (meth) Polyalkylene glycol mono (meth) acrylates such as acrylate, polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, methoxypolypropylene glycol mono (meth) acrylate; N-vinyl-2-pyrrolidone, N-vinylsuccinimide N-vinyl monomers such as N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, etc. Monomer, vinyl methyl ether; but like, but is not particularly limited. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

  Among the ethylenically unsaturated monomers exemplified above, those composed of an ethylenically unsaturated monomer having a nonionic group and / or a sulfonic acid (salt) group are more preferable because of high salt resistance. Examples of the monomer include 2- (meth) acrylamide-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, (meth) acrylamide, and hydroxyalkyl. (Meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate and the like can be mentioned. Furthermore, an ethylenically unsaturated monomer having a polyoxyalkylene group is particularly preferred.

  As a more preferable combination when two or more ethylenically unsaturated monomers are used in combination as the monomer component, for example, a combination of an alkali metal salt of (meth) acrylic acid such as sodium acrylate and acrylamide, (meta ) A combination of an alkali metal salt of acrylic acid and methoxypolyethylene glycol mono (meth) acrylate is exemplified, but is not particularly limited.

  A water-absorbing resin (a) is obtained by polymerizing the monomer components. The average molecular weight, shape, average particle size, etc. of the water-absorbent resin (a) may be set according to the composition of the friction reducing agent coating, the type of binder, physical properties, working environment, etc., and are particularly limited. However, the average particle diameter of the water absorbent resin (a) is preferably 30 to 800 μm, more preferably 30 to 600 μm, and most preferably 30 to 400 μm.

  When the average particle diameter of the water-absorbent resin (a) used in the friction-reducing resin coating exceeds 800 μm, the particle diameter is too large, and the water-absorbent resin (a) is added to the solvent (c) solution of the hydrophilic binder resin (b). When mixed, the particles of the water absorbent resin (a) are liable to settle, which is not preferable.

  On the other hand, when the average particle diameter of the water-absorbent resin (a) is less than 30 μm, the handling becomes very difficult (e.g., it is easily scattered as a fine powder), which is not preferable.

Next, the hydrophilic binder resin (b) constituting the friction-reducing resin paint will be described.
The hydrophilic binder resin (b) used in the friction reducing resin coating is (i) water-soluble or water-swellable, and (ii) has a function of fixing the water-absorbing resin (a) to the substrate as a binder. And (iii) is not particularly limited as long as it is soluble in the solvent (c). For example, (meth) acrylic acid ester copolymer, polyurethane, polyester, polycarbonate, polyvinyl alcohol resin, poly Examples thereof include a partial hydrolyzate of vinyl acetate and an ethylene-polyvinyl alcohol copolymer, and one or a mixture of two or more thereof can be used.

  If the hydrophilic binder resin (b) is too low in hydrophilicity, it inhibits the swelling of the water-absorbent resin (a), reduces the absorption of moisture in the soil, and reduces the friction reducing function of the paint for friction reducing agent. This is not preferable. On the other hand, when the hydrophilicity of the hydrophilic binder resin (b) is too high, the adhesive force of the binder to the base material is excessively reduced when water is absorbed in the soil, and the entire coating film is peeled off too quickly. For the reasons as described above, the hydrophilic binder resin (b) preferably has moderate hydrophilicity.

  The acid value of the hydrophilic binder resin (b) is preferably 40 mgKOH / g or more, more preferably 50 mgKOH / g or more, and more preferably 70 mgKOH / g or more in order to have appropriate hydrophilicity. preferable.

  When the acid value of the hydrophilic binder resin (b) is less than 40 mgKOH / g, the hydrophilicity becomes too low, which is not preferable. Moreover, in order to maintain the binder function at the time of water absorption, it is preferably 500 mgKOH / g or less, more preferably 300 mgKOH / g or less, and even more preferably 200 mgKOH / g or less. When the acid value of the hydrophilic binder resin (b) exceeds 500 mgKOH / g, the hydrophilicity becomes too high, which is not preferable.

  Next, the glass transition temperature of the hydrophilic binder resin (b) is not particularly limited, but the adhesion to the friction-reducing metal sheet 21 serving as the base material and the workability when the base material is embedded in the ground G From the viewpoint of coexistence of the toughness of the coating film of the friction-reducing resin coating, it is preferable to have a glass transition temperature of -20 ° C to 120 ° C. When the glass transition temperature is −20 ° C. or lower, the coating film of the friction-reducing resin coating tends to be sticky. In particular, when the substrate after application is immediately wound and left, blocking may occur. In addition, since the strength of the friction-reducing resin coating is insufficient, it is not preferable because the base material is easily peeled when embedded in the ground G. For this reason, the glass transition temperature is more preferably 0 ° C. or higher.

  In addition, when the glass transition temperature of the hydrophilic binder resin (b) is 120 ° C. or higher, the adhesion preventing material layer becomes too hard, the adhesion to the base material, the flexibility of the coating film of the friction reducing resin paint becomes poor, Again, when the base material is embedded in the ground G, peeling and dropping of the water absorbent resin (a) are likely to occur, which is not preferable. From this, the glass transition temperature is more preferably 100 ° C. or less, and when the glass transition temperature is between 0 ° C. and 20 ° C. and between 20 ° C. and 100 ° C., the softening component and the shape retention component Good balance and more preferable.

  The weight average molecular weight (Mw) of the hydrophilic binder resin (b) is not particularly limited, but is preferably in the range of 30,000 to 300,000, and more preferably in the range of 50,000 to 200,000. By using the above resin having a weight average molecular weight, it becomes easy to balance toughness and solubility.

  As the hydrophilic binder resin (b), it is preferable to use an alkali water-soluble resin or a resin having an acid value of 40 to 500 mgKOH / g because the hydrophilicity can be easily adjusted by adjusting the acid value.

  Below, alkali water soluble resin is demonstrated. The alkaline water-soluble resin, which is one of the hydrophilic binder resins (b) constituting the friction-reducing resin coating, is a resin that dissolves in a 0.4% by weight NaOH aqueous solution and does not dissolve in neutral or acidic water. is there. The alkaline water-soluble resin is not particularly limited as long as it has the solubility defined above. For example, co-polymerization of an α, β-unsaturated carboxylic acid monomer and other monomers copolymerizable therewith. Coalescence can be mentioned.

  In addition, although it is the solubility to the above-mentioned alkaline water, the solubility degree is not particularly limited, but the preferable solubility degree of the alkaline water-soluble resin as a binder resin that can be preferably used in the following description is shown. Moreover, although it is the term alkaline water-soluble resin, it may be expressed as an alkali-soluble resin in another expression. Since it is clearer to use the alkaline water-soluble resin, the alkaline water-soluble resin is used in this specification.

  Moreover, although it is the solubility to the alkaline water of the alkaline water soluble resin which can be used preferably, it will not specifically limit unless the desired friction reduction effect | action is inhibited.

  This value is preferably 50% -100% for the alkaline water-soluble resin. More preferably, it is 60-100%. More preferably, it is 70-100 weight%. If no resin remains after filtration, it is dissolved.

  The production method of the alkaline water-soluble resin and the hydrophilic binder resin having an acid value of 40 to 500 mgKOH / g is not particularly limited, but the following α, β-unsaturated carboxylic acid monomer can be copolymerized with α, β- A copolymer obtainable by polymerization using an unsaturated monomer component composed of a monomer other than the unsaturated carboxylic acid monomer is preferred.

  For example, as an α, β-unsaturated carboxylic acid monomer used for the production of an alkaline water-soluble resin and a hydrophilic binder resin having an acid value of 40 to 500 mgKOH / g, for example, acrylic acid, methacrylic acid, maleic acid Α, β-unsaturated carboxylic acids such as itaconic acid and fumaric acid; α, β-unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; maleic acid monoester, fumaric acid monoester and itaconic acid mono Examples include α, β-unsaturated dicarboxylic acid monoesters such as esters. The α, β-unsaturated carboxylic acid monomer may be only one type or two or more types. Among these, acrylic acid and / or methacrylic acid, which are acrylic α, β-unsaturated carboxylic acids, are preferably used because they are inexpensive and have good copolymerizability with other unsaturated monomers.

  Next, other monomers that can be copolymerized with the α, β-unsaturated carboxylic acid monomer include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl Esters of C1-C18 monohydric alcohols such as methacrylate, butyl methacrylate, stearyl methacrylate and (meth) acrylic acid; nitrile group-containing vinyl monomers such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, etc. Amide group-containing vinyl monomers; hydroxyl group-containing vinyl monomers such as hydroxyethyl acrylate and hydroxypropyl methacrylate; epoxy group-containing vinyl monomers such as glycidyl methacrylate; zinc acrylate , Metal salts of α, β-unsaturated carboxylic acids such as zinc methacrylate; aromatic vinyl monomers such as styrene and α-methylstyrene; aliphatic vinyl monomers such as vinyl acetate; vinyl chloride, odor Halogen-containing vinyl monomers such as vinyl iodide, vinyl iodide and vinylidene chloride; allyl ethers; maleic acid derivatives such as dialkyl esters of maleic acid; fumaric acid derivatives such as dialkyl esters of fumaric acid; maleimide, N-methyl Maleimide derivatives such as maleimide, stearylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide; Itaconic acid derivatives such as mono and dialkyl esters of itaconic acid, itaconic amides, itaconic imides, itaconic amide esters; alkenes such as ethylene and propylene Class: butadiene, isoprene and other die Vinyl ethers; unsaturated monomers having a sulfonic acid (salt) group such as 2- (meth) acryloylpropanesulfonic acid (salt), 3-allyloxy-2-hydroxypropanesulfonic acid (salt), polyalkylene A glycol (meth) acrylate etc. can be mentioned, It can use by 1 type (s) or 2 or more types in these.

  Among these, (meth) acrylic acid alkyl esters are easily available as esters having various properties, and by appropriately combining them, the binder resin Tg (hardness, softness), base material The adhesiveness to the resin can be easily adjusted, and the copolymerizability with the α, β-unsaturated carboxylic acid monomer is relatively good, which is preferable.

  The (meth) acrylic acid alkyl ester is preferably used in an amount of 30% to 100% by weight based on 100% by weight of the total amount of other monomers copolymerizable with the α, β-unsaturated carboxylic acid monomer. More preferably, it is used in an amount of 50 to 100% by weight. More preferably, it is 60-100 weight%, More preferably, it is 70-100 weight%. That is, the use of an acrylic monomer as another monomer is a preferred embodiment as a form of an alkaline water-soluble resin as the hydrophilic binder resin (b).

  The proportion of the unsaturated monomer component composed of the above α, β-unsaturated carboxylic acid monomer and another monomer copolymerizable therewith is not particularly limited. For example, α, β-unsaturated carboxylic acid When the unsaturated monomer component consisting of a monomer and another monomer copolymerizable therewith is 100% by weight, the proportion of α, β-unsaturated carboxylic acid in the total monomer component is preferably Is 7 to 80% by weight in the total amount of unsaturated monomers. More preferably, it is 7 to 50% by weight. More preferably, it is 9 to 30% by weight.

  When the ratio of the α, β-unsaturated carboxylic acid monomer in all monomers in the alkaline water-soluble resin is less than 7% by weight, the hydrophilicity tends to be too low due to the low acid value. On the other hand, if the ratio exceeds 80% by weight, the hydrophilicity becomes too high, and problems are likely to occur.

  Α, β-unsaturation used as a raw material for producing a hydrophilic binder resin having an acid value of 40 mgKOH / g or more and 500 mgKOH / g or less, that is, a binder resin obtained by polymerizing the unsaturated monomer component. The amount of the copolymerizable monomer other than the carboxylic acid monomer is the unsaturated monomer comprising the above α, β-unsaturated carboxylic acid monomer and another monomer copolymerizable therewith. Based on 100% by weight of all components, preferably 93 to 20% by weight in all of the unsaturated monomer components. More preferably, it is 93 to 50% by weight. More preferably, it is 91-70 weight%.

  If the proportion of the α, β-unsaturated carboxylic acid monomer is less than 20%, the hydrophilicity is lowered, and if it exceeds 93%, the hydrophilicity becomes too high.

  The method for producing the alkaline water-soluble resin is not particularly limited, and generally known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization and the like can be used, and among them, it is manufactured by solution polymerization in an organic solvent. Is preferred.

  This is because a friction-reducing resin coating can be produced by mixing a water-absorbing resin as it is with a solution or dispersion containing an alkaline water-soluble resin obtained by solution polymerization.

  Moreover, radical polymerization, anionic polymerization, cationic polymerization, coordination polymerization, etc. are mentioned as a polymerization form, However, radical polymerization is preferable as an industrial manufacturing method.

  Examples of the reaction vessel used for the production of the raw material polymer include a tank reactor and a tubular reactor such as a kneader and a static mixer. These reactors can be used in combination as required. A dripping tank is also used if necessary. The pressure in the reaction vessel may be any of reduced pressure, normal pressure, and increased pressure.

  Next, the radical polymerization initiator used in the radical polymerization is not particularly limited. Specific examples thereof include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl). Azo initiators such as valeronitrile) and peroxide initiators such as benzoyl peroxide and di-t-butyl peroxide. Two or more kinds of these radical polymerization initiators may be used in combination.

  The solvent used in the solution polymerization is not particularly limited as long as it does not interfere with the radical polymerization reaction. For example, alcohols such as methanol, ethanol and isopropyl alcohol; aromatic hydrocarbons such as benzene and toluene; acetone , Ketones such as methyl ethyl ketone; aliphatic esters such as ethyl acetate and butyl acetate; ethylene glycol derivatives such as ethylene glycol and ethylene glycol monomethyl ether; propylene glycol derivatives such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate Etc. Two or more of these solvents may be used in combination.

  Next, the solvent (c) used for the friction-reducing resin paint will be described. The solvent (c) can be used without any particular limitation as long as it is a known solvent used for ordinary paints, for example, one or more of the solvents exemplified in the description of the method for producing the alkaline water-soluble resin. It can be used in a combination of two or more.

  Further, as a method for selecting the solvent (c), it is preferable to select a solvent having a boiling point, safety, etc. suitable for application to the substrate. If a low-boiling solvent is selected, it can be quickly dried and a coating can be formed in a short time, so that thick coating and the like are easy, and if a high-boiling solvent is selected, the working time can be extended. By using an organic solvent as a medium, the water-absorbing resin does not swell due to water absorption when a medium containing water is used, and the coating operation is facilitated because it does not become a gel. In addition, when a highly volatile solvent such as methyl ethyl ketone or methanol is used, it can be dried in about 10 minutes and can be transferred to the next operation or process quickly because it dries much faster than when water is used as a medium. The construction period or the time required for application to the substrate can be remarkably shortened.

  As long as the friction-reducing resin paint of the present invention contains the water-absorbent resin (a), the hydrophilic binder resin (b) and the solvent (c) described above as essential components, the characteristics thereof are not impaired. As other additives (h), other resins, pigments, various stabilizers, various fillers and the like may be contained.

  The ratio of the water-absorbing resin (a), the hydrophilic binder (b) and the solvent (c) to the other additive (h) is not particularly limited, but in order to fully exhibit the characteristics of the friction-reducing resin paint, Ratio ([(a) + (b) + (c)] / [(a) + (b) + () of the total of the resin (a), the hydrophilic binder (b) and the solvent (c)) c) + (h)] × 100 (%)) is preferably 50% or more, more preferably 70% or more, and most preferably 80% or more.

  Also, the ratio of the water-absorbing resin (a), the hydrophilic binder (b), the solvent (c) and other additives (h) is not particularly limited, but in order to fully exhibit the characteristics of the friction-reducing resin paint. The water-absorbing resin (a) is 5 to 60% by weight, the hydrophilic binder (b) is 10 to 70% by weight, the solvent (c) is 5 to 70% by weight, and the other additives (h) are 0 to 50% by weight. %, The water-absorbing resin (a) is 10 to 50% by weight, the hydrophilic binder (b) is 10 to 60% by weight, the solvent (c) is 10 to 60% by weight, and the other additives (h) are 0%. -30% by weight is more preferred.

  The method of applying the friction-reducing resin paint to various substrates is not particularly limited as long as it is a known paint application method. For example, a brush, a roller or the like may be used, or a spray device such as a lysing gun is used. Spray painting.

  In this embodiment, the friction reducing resin coating material forming the friction reducing material layer 300 is also applied or pasted on the outer surface of the friction reducing metal sheet 21. The friction-reducing metal sheet 21 coated with such a friction-reducing resin coating is gradually drawn downward as the caisson housing 1 is press-fitted and settled, and can be pulled upward after the caisson housing 1 is pressed and settled. It is configured as follows. That is, as shown in FIG. 9A, the winding shaft 24 is provided with a locking slit 32 penetrating in a direction perpendicular to the shaft, and as shown in FIG. 9B, the friction reducing metal sheet. The friction reducing metal sheet 21 is inserted by inserting the winding base end 33 of the coil 21 into the locking slit 32 and winding the friction reducing metal sheet 21 around the winding shaft 24 as shown in FIG. Is attached to the winding shaft 24.

  The friction-reducing metal sheet 21 wound around the take-up shaft 24 is gradually fed by the caisson housing 1 being press-fitted and settled with the feeding tip 34 of the friction-reducing metal sheet 21 held on the ground. Go (Figure 7). And since the connection state with the winding shaft 24 is finally released when the winding base end portion 33 of the friction reducing metal sheet 21 passes through the locking slit 32, the friction reducing metal sheet 21 is pulled upward. Be able to.

  Next, the press-fitting caisson method of the present invention executed by using such a caisson housing 1 will be described. In the press-fitting caisson method of the present invention, the caisson casing 1 of the present invention described above is used, and the friction-reducing metal sheet 21 in the wound state is gradually drawn downward by press-fitting the caisson casing 1. In addition, the sliding contact between the ground G and the caisson housing 1 or the subsequent housing 4 added above is prevented, and after the caisson housing 1 is pressed and settled, the winding base end 33 is connected to the caisson housing 1. It is characterized in that it is configured so that it can be released and pulled upward.

  Hereinafter, a specific configuration of the press-fitting caisson method according to the present invention will be described with reference to FIGS. That is, the press-fitting caisson method of the present invention includes (1) edge cutting / mound installation step, (2) primary press-fitting preparation step, (3) primary press-fitting / excavation step, (4) secondary press-fitting preparation step, (5) ) Secondary press-fitting / excavation step, (6) press-fitting / excavation completion step, (7) friction reducing metal sheet drawing step, and (8) bottom slab concrete placing step.

(1) Edge cutting and mound setting process (see Fig. 5 (a))
In this step, a steel sheet pile 3 or the like is placed in the ground G in order to cut the ground G forming the caisson shaft 5 and the surrounding ground. Incidentally, when the steel sheet pile 3 or the like is placed, propagation of vibrations and the like given to the surrounding ground is prevented, and various effects caused by the propagation are blocked. A mound (replacement sand) M is provided in preparation for the installation of the caisson housing 1.

(2) Primary press-fitting preparation process (see FIG. 5B)
In this step, the earth anchor 17 is driven and the pressure girder 9 is bridged over the earth anchor 17. Then, the hydraulic jack 13 is installed on the pressure beam 9 and the upper portion of the earth anchor 17 is chucked by the anchor chuck 18. In addition, the caisson housing 1 is set on the lower surface of the presser girder 9 with the caisson blade edge 2 facing downward to prepare for press-fitting of the caisson housing 1.
At this time, the feeding leading end 34 of the friction reducing metal sheet 21 is held by the pressure beam 9 or the like.

(3) Primary press-fitting and excavation process (see FIGS. 5C and 7A)
In this step, the caisson housing 1 is press-fitted and settled into the ground G by the press-fitting action using the pressure girder 9 and the weight of the caisson housing 1 and the hydraulic pressure of the hydraulic jack 13. Then, excavation of the ground G inside the caisson housing 1 is advanced using the crane 7 and the grab bucket 14 while the press-fitting and sinking of the caisson housing 1 is advanced.

  At this time, the sheet unit 29 attached to the caisson housing 1 also moves downward as the caisson housing 1 is press-fitted and settled, so that the friction reducing metal sheet 21 in the wound state is unwound little by little.

(4) Secondary press-fitting preparation process (see FIG. 5 (d))
In this step, after the press-in sedimentation of the caisson housing 1 is completed, preparations for the press-in sedimentation of the subsequent housing 4 to be added above the caisson housing 1 are performed. In this case, the installed pressure girder 9, hydraulic jack 13 and the like are temporarily removed using the crane 7 and the hanging hook 16 and the like. Then, the scaffold 8 and the mold 10 are installed, the raw material is poured into the mold 10 above the caisson casing 1 press-fitted into the ground G, and the subsequent casing 4 is precast. And after confirming solidification of the subsequent frame 4, the said scaffold 8 and the formwork 10 are removed.

(5) Secondary press-fitting and excavation process (see FIGS. 6 (a), 7 (b) and 7 (c))
In this step, the pressure girder 9 is again laid over the earth anchor 17, the hydraulic jack 13 is installed on the pressure girder 9, and the upper portion of the earth anchor 17 is chucked by the anchor chuck 18. Then, similarly to the above (3) primary press-fitting and excavation process, excavation of the ground G inside the caisson housing 1 is advanced while the press-in settling of the caisson housing 1 and the subsequent housing 4 is preceded.

  Further, at this time, the friction reducing metal sheet 21 coated with the friction reducing material layer 30 is located between the outer peripheral surface of the caisson casing 1 and the subsequent casing 4 and the outer ground G. The frictional resistance is kept extremely low, and the caisson housing 1 and the following housing 4 are smoothly and smoothly pressed into the ground G.

  That is, the friction reducing sheet unit is attached to the outer peripheral surface of the tip of the caisson casing 1 that is in sliding contact with the ground G, and the roll friction reducing sheet 21 is unwound along with the press-fitting and sinking of the caisson 1, and the friction reducing sheet 21 is gradually removed. By using it so as to extend into the ground G, sliding resistance between the ground G and the caisson 1 can be completely avoided. Further, the sliding contact resistance between the friction reducing sheet 21 and the caisson 1 can be greatly reduced by the friction reducing material layer 30.

  Further, the operation of the friction reducing sheet unit 29 will be described. The box 230 in which the roll-shaped friction reducing sheet 21 is accommodated is filled with a granular water-stopping agent 28 that swells when it comes into contact with water and develops water-stopping properties. Therefore, when water enters from the feeding opening 27 of the friction reducing sheet 21, simultaneously with the intrusion, the water contacts and reacts with the granular water-stopping agent 28 in the vicinity of the feeding opening 27, thereby swelling. 27 is sealed by the sealing portion 280 to be blocked from the outside, that is, water-stopping is developed, and water intrusion into the box 230 is prevented (FIG. 11).

  When the friction reducing sheet 21 is drawn out from the feeding opening 27, the sealing state due to the swelling is broken and water enters from there, but immediately reacts with the unreacted water stop agent 28 and newly swells, The feeding opening 27 is sealed again.

  According to the present embodiment, the water-stopping agent 28 filled in the box 230 prevents water from entering the box 230, so that there is no possibility that the friction reducing material layer 30 is deteriorated by water. When the friction reducing sheet 21 is drawn out of the box 230 and should exhibit the friction reducing function, the friction reducing function can be surely exhibited.

  Further, in this embodiment, the friction reducing material layer 30 of the friction reducing sheet 21 swells when it comes into contact with water, and is formed of a material that exhibits a friction reducing function by this swelling. This type of friction reducing material layer 30 is excellent in the effect of reducing sliding friction with the caisson 1. This is an effect obtained when the friction reduction sheet 21 is slidably contacted with the caisson 1 while being swollen in contact with the water in the ground G after being drawn out of the box 230. When the friction reducing sheet 21 comes into contact with water in the box 230 before being fed out of the box 230, it reacts and swells there, and the friction reducing material layer 30 is peeled off when the friction reducing sheet 21 is fed out of the box 230. When the reduction function should be exhibited, there is a possibility that the function cannot be exhibited. According to the present embodiment, as described above, this possibility can be surely reduced.

  Further, in this embodiment, the box 230 is formed in a double tube structure of the inner box 25 and the outer box 23, the roll-shaped friction reducing sheet 21 is accommodated in the inner box 25, and the waterstop agent 28 is contained in the inner box 25. And the space between the outer box 23 is filled. Therefore, even if the roll of the friction reducing sheet 21 is reduced in use, the friction reducing sheet 21 is accommodated in the inner box 25, while the water-stopping agent 28 is contained in the inner box 25 and the outer box 23. Since it is filled in the space between, it is not affected. Accordingly, the water stop agent 28 can be present in the box 230 without being affected by the roll size of the roll-shaped friction reducing sheet 21, so that the feeding opening 27 can be reliably sealed. .

Further, in this embodiment, the breakdown voltage reinforced portions comprising integrally formed with a reinforcing rib 23 1 on the inner wall surface of the outer box 23 is provided. In the ground G, soil water pressure is received from the outside of the outer box 23, but water does not enter the outer box 23 by the water-stopping agent 28, so the pressure in the outer box 23 becomes smaller than the external soil water pressure, and the pressure balance Collapses. Therefore, there is a possibility that the outer box 23 is crushed pushed in soil water pressure, according to this embodiment, since the reinforcing ribs 23 1 are provided in the outer box 23 can be prevented from being crushed.

  Furthermore, according to the present embodiment, when the caisson casing 1 is press-fitted and settled, the friction reducing metal sheet 21 that is gradually drawn out and extended in a long length is subjected to friction resistance for the longest time at the feeding tip side. The friction reducing material layer 30 is configured such that the thickness of the friction reducing material layer 30 is the largest and the thickness of the friction reducing material layer 30 is gradually reduced toward the winding base end that receives the frictional resistance for the shortest time. Accordingly, it is possible to prevent a decrease in the friction reducing action due to peeling or wear of the friction reducing material layer 30 without excessively increasing the amount of the friction reducing material layer 30 used.

(6) Press-in and excavation completion process (see Fig. 6 (b))
Hereinafter, by repeating the above (4) secondary press-fitting preparation step and (5) secondary press-fitting and excavation step, all of the caisson housing 1 and the predetermined number of subsequent housings 4 are pressed and settled, and the ground G inside the caisson housing 1 Complete excavation. Further, while the excavation of the ground G is proceeding, there is a case where it reaches the part where the groundwater W or the like flows on the way. In such a case, the groundwater W or the like flowing into the caisson housing 1 and the subsequent housing 4 is not shown. And so on.

(7) Friction reducing metal sheet drawing process (see FIG. 6C)
When the caisson housing 1 is pressed and settled, the winding base end portion 33 of the friction reducing metal sheet 21 is disengaged from the locking slit 32 of the winding shaft 24 that has been locked, so that the friction reducing metal sheet 21 is pulled upward. Is possible. Along with this, the friction reducing metal sheet 21 is pulled upward, and the earth anchor 17, the pressure girder 9, the hydraulic jack 13, the steel sheet pile 3 and the like are removed.

  At this time, in this embodiment, since the friction reducing material layer 300 is applied or pasted on the outer surface of the friction reducing metal sheet 21, the outer surface of the friction reducing metal sheet 21 is ground G when the friction reducing metal sheet 21 is pulled out. The frictional resistance due to the sliding contact can be effectively reduced. Further, the inner surface of the friction reducing metal sheet 21 is in sliding contact with the outer peripheral surfaces of the caisson pair 1 and the extension pair 4, and the frictional resistance due to this sliding contact can be effectively reduced by the friction reducing material layer 30. it can. Furthermore, since the friction reducing metal sheet 21 is configured to be pulled upward, the friction reducing metal sheet 21 that has been used can be collected, and material costs can be reduced through effective use of the members. In addition, adverse effects on the natural environment and the like can be prevented through preventing the friction reducing material layer from remaining in the ground.

(8) Bottom slab concrete placing process (see Fig. 6 (d))
Then, the caisson shaft 5 having a predetermined depth is completed by placing the underwater concrete 12 and the bottom slab concrete 11 inside the caisson frame 1 that has been press-fitted and settled. The caisson shaft 5 is used as a start shaft or a reaching shaft of the shield tunnel 15.

In the above description, the case where one type of water-stopping agent 28 is filled in the outer box 23 has been shown, but the water-stopping agent 28 can be used in a combination of a plurality of types. For example, two layers in which a powder such as bentonite is filled from the bottom of the outer box 23 to a height at which the inner box 25 is almost buried, and the water-absorbent resin (a) is filled on the upper opening 27 to fill it up. It may be structured . Since the bottom side of the box usually has almost no water intrusion, it is desirable to measure whether the cost is low by using a material whose swelling amount is smaller than that of the feeding opening 27 side. Of course, you may comprise in three or more layers. Even in the case of three or more layers, it is desirable to use a material with a smaller amount of swelling toward the back of the outer box 23 in order to reduce the cost of the material.

[Example 2]
Next, the caisson housing 1 according to the second embodiment in which the configuration of the friction reducing sheet unit 29 illustrated in FIGS. 13 to 15 is different will be described. FIG. 13 is an enlarged perspective view showing a part of the friction reducing sheet unit arranged in the upper and lower two stages of the annular shape, and FIG. 14 shows two types of friction reducing by changing the shape of the box and the shaft diameter of the winding shaft. It is a sectional side view which shows a sheet unit (a) (b). FIG. 15 is a cross-sectional view showing various modes (a) to (c) of the close contact means applied between the main sheet and the joint sheet. The caisson housing 1 according to the second embodiment is the same as the first embodiment except for the difference in the arrangement of the friction reducing sheet unit 29 and the partial configuration of the friction reducing sheet unit 29 and the friction reducing metal sheet 21. Since it is the same as that of the caisson housing 1, here, the description will focus on a specific configuration of the caisson housing 1 according to the second embodiment.

  In the second embodiment, the friction reducing metal sheet 21 is disposed in the gap 36 between the main sheet 35 provided in a substantially connected state along the outer peripheral surface of the caisson housing 1 and the adjacent main sheets 35. The joint sheet 37 is provided. The main seat 35 and the joint seat 37 are partially overlapped in a state of being wound so as not to interfere with each other, and are provided in a state where the mounting positions are shifted up and down. Specifically, as shown in FIG. 13, the seat unit 29 </ b> A for the main seat 35 is positioned above, and the sheet unit 29 </ b> B for the joint seat 37 is positioned below by a half pitch shift in the circumferential direction. ing. Accordingly, the gap 36 existing between the adjacent main sheets 35 is closed by the joint sheet 37 as shown in the figure, so that it is difficult for mud R and groundwater W to flow in from the outside.

  In FIG. 13, a box 230 (outer box 23 and inner box 25) is provided for each individual seat unit 29. However, as shown in FIG. 14, a main seat 35 located above and a joint seat 37 located below. It is also possible to use a vertically long box 230 (the outer box 23 and the inner box 25) that can accommodate the two at the same time. Incidentally, in FIG. 14A, a partition plate 38 that partitions the main sheet 35 and the joint sheet 37 is provided at a height near the center and the center of the outer box 23, and the winding shafts of the main sheet 35 and the joint sheet 37 are respectively provided. The same diameter is shown in FIG. On the other hand, in FIG. 14B, the partition plate 38 does not exist, and the main shaft 35 has a small diameter on the main shaft 35 side and a large diameter on the winding shaft 24 on the joint sheet 37 side. In the figure, the joint sheet 37 is smoothly drawn out.

  Further, the contact surface between the main sheet 35 and the joint sheet 37 is provided with a contact means 39 as shown in FIG. 15 for bringing the main sheet 35 and the joint sheet 37 into a contact state in use, or the contact means 39 acts. It is also possible to configure. Incidentally, FIG. 15A shows a close contact means 39 provided with a concave and convex engaging portion 40 that engages with the joint surface of the main sheet 35 to the joint sheet 37 and the joint surface of the joint sheet 37 to the main sheet 35. .

  Further, in FIG. 15B, a seal member 41 for improving the adhesion of the joint surface is provided between the main sheet 35 and the joint sheet 37, and friction-reducing air A injected from the inside of the caisson housing 1 is provided. A close contact means 39 is shown in which the pressure between the main sheet 35 and the joint sheet 37 is increased by using the pressure of the pressure. In this case, the seal member 41 can be replaced by a friction reducing resin material 30 applied to the surface of the friction reducing metal sheet 21. Further, as shown in FIG. 15 (c), the friction reducing resin material 30 may be applied in a streak shape so as to function also as the uneven engagement portion 40.

[Other embodiments]
The friction reducing sheet unit 29, the caisson housing 1 and the press-fitting caisson method using the caisson housing 1 according to the present invention have the above-described configuration as an example, but within the scope not departing from the gist of the present invention. Of course, it is possible to change or omit the partial configuration. For example, the shape of the caisson housing 1 is not limited to a cylindrical shape, and may be a square tube shape. If the rectangular tube-shaped caisson housing 1 is used, a rectangular tube shape as shown in FIGS. The caisson shaft 5 can be constructed. Further, the caisson shaft 5 that can be constructed by the caisson housing 1 of the present invention is not limited to the structure shown in FIGS. 8A and 8B in which the subsequent housing 4 formed in a cylindrical shape is added from the beginning. A structure as shown in FIGS. 8C and 8D in which the plate-like piece 19 is joined using the bolt joint 42 is also included.

  Further, the succeeding casing 4 crushed on the caisson casing 1 is not limited to a concrete casing but may be a casing formed of other materials such as steel. Further, the width dimension of the main sheet 35 and the joint sheet 37 is not necessarily the same dimension, and the width dimension of the joint sheet 37 can be shortened within a range in which the gap portion 36 can be closed.

  Further, the friction reducing material layers 30 and 300 provided on the surface of the friction reducing metal sheet 21 are not limited to those according to the above-described embodiment in which the raw material of the friction reducing material layer in a molten state is applied and then dried and cured. Of course, the sheet-like friction reducing material layer 30 in a solid state may be pasted using an adhesive or the like from the beginning.

  The present invention can be used when building a caisson shaft using a caisson skeleton at a construction site of a bridge pier or a shield work, especially when the frictional resistance when pressuring and sinking the caisson skeleton is large. It can be used when you want to reduce the pressure caisson method efficiently.

It is a sectional side view which shows an example of the mechanical installation used for execution of the press-fitting caisson method using the caisson housing of this invention. It is a top view which shows an example of the mechanical installation used for execution of the press fit caisson method using the caisson housing of this invention. It is a sectional side view which shows an example of the caisson housing of this invention. It is a cross-sectional view showing an example of the caisson housing of the present invention. It is side sectional drawing of the first half part (a)-(d) which shows an example of the press-fitting caisson method of this invention according to a process. It is a sectional side view of the latter half part (a)-(d) which shows an example of the press-fitting caisson method of this invention according to a process. It is a sectional side view which shows the extension state of the friction reduction metal sheet drawn out with the press-fit sedimentation of a caisson housing. It is a perspective view which shows the various aspect of the caisson shaft constructed | assembled by the caisson frame of this invention. It is a perspective view which shows the latching state of the winding base end part of a friction reduction metal sheet in steps. It is a perspective view which expands and shows some sheet units arrange | positioned by the annular | circular shape. It is a sectional side view showing an example of a friction reduction sheet unit concerning the present invention. It is a horizontal sectional view of the same friction reduction sheet unit. It is a perspective view which expands and shows a part of sheet unit arrange | positioned at the annular | circular shaped upper and lower two steps. It is a sectional side view showing two types of sheet units (a) and (b) in which the shape of the sheet magazine and the shaft diameter of the take-up shaft are different. It is a cross-sectional view which shows the various aspects (a)-(c) of the contact | adherence means applied between a main sheet | seat and a joint sheet | seat.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Caisson frame, 2 Caisson blade, 3 Steel sheet pile, 4 Subsequent frame, 5 Caisson shaft 6 Machine equipment, 7 Crane, 8 Scaffolding, 9 Pressing girder, 10 Formwork 11 Bottom plate concrete, 12 Underwater concrete, 13 Hydraulic jack (Press-fit device), 14 Grab bucket, 15 Shield tunnel, 16 Hanging hook, 17 Earth anchor, 18 Anchor chuck, 19 pieces, 20 Housing part, 21 Friction reducing metal sheet, 22 Sheet installation part, 23 Outer box, 24 rolls Take-up shaft, 25 inner box, 26 slit, 27 feeding opening, 28 water stop agent, 29 friction reducing sheet unit, 29A seat unit (for main seat), 29B seat unit (for joint seat), 30 friction reducing material Layer, 31 inner surface, 32 locking slit, 33 Winding base end part, 34 Feeding tip part, 35 Main sheet, 36 Gap part, 37 Joint sheet, 38 Partition plate, 39 Contact means, 40 Concavity and convexity engaging part, 41 Seal member, 42 Bolt joint, 230 Box, 231 Reinforcement Rib, 233 rubber plate, 280 sealing part, 300 friction reducing material layer, A air, G ground, R mud (earth and sand), M mound (substitution sand), W ground water, a water-absorbing resin, b hydrophilic binder resin, c solvent, h additive,

Claims (7)

  The friction reducing sheet is wound into a roll shape, and the rolled friction reducing sheet, in which the friction reducing material layer is provided on at least one surface of the sheet in the wound state, is accommodated in the box so as to be fed out. A friction-reducing sheet unit, which is filled with a powdery water-stopping agent that can swell when it comes into contact with water to develop water-stopping properties.   2. The friction reducing sheet unit according to claim 1, wherein the friction reducing material layer of the friction reducing sheet swells when contacted with water, and is formed of a material that exhibits a friction reducing function by the swelling. Friction reduction sheet unit. A friction reducing sheet unit according to claim 1 or 2, in the interior of the box, in a ground, wherein the friction reducing sheet unit is used, the withstand voltage reinforcing portion is provided for the soil water pressure to which the box is subjected from the outside A friction-reducing sheet unit characterized by   The friction reducing sheet unit according to any one of claims 1 to 3, wherein the box is formed in a double tube structure of an inner box and an outer box, and the roll-like friction reducing sheet is accommodated in the inner box, The friction-reducing sheet unit, wherein the water-stopper is filled in a space between the inner box and the outer box.   The friction reducing sheet unit according to any one of claims 1 to 4, wherein the water-stopping agent is composed of different types of multilayers, and the water-stopping agent stacked on the delivery opening side of the box is stacked on the back side. A friction-reducing sheet unit, characterized in that it is made of a material that swells more by contact with water than a water-stopping agent. The caisson housing with the inner blade-shaped caisson blade tip formed at the tip is pressed and settled into the ground for each predetermined stroke, and the mud soil inside the caisson housing is excavated and discharged to the outside. The caisson housing used in the press-fitting caisson method for constructing a caisson shaft with a predetermined depth by adding and installing
In the caisson housing, the friction reducing sheet unit according to any one of claims 1 to 5 is arranged in a substantially connected state over a plurality of locations so as to follow the outer peripheral surface of the caisson housing, A caisson housing characterized in that the friction reducing sheet is gradually drawn out as the caisson housing is pressed and settled. The caisson housing with the inner blade-shaped caisson blade tip formed at the tip is pressed and settled into the ground for each predetermined stroke, and the mud soil inside the caisson housing is excavated and discharged to the outside. It is a press-in caisson method for constructing caisson shafts of a predetermined depth by adding and installing
The caisson casing according to claim 6 is used as the caisson casing, and the friction reducing sheet is gradually drawn downward by press-fitting and sinking the caisson casing in a state where the leading end portion of the friction reducing sheet is held, A press-fitting caisson method using a caisson casing, wherein the caisson casing or a subsequent casing added above the caisson casing is in sliding contact with the friction reducing sheet through the friction reducing material layer.

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