JP3711541B2 - Ready-made pile embedding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ready-made pile embedding method in which a ready-made pile having a tubular shape made of steel or concrete is installed in the ground.
[0002]
[Prior art]
Conventionally, the ready-made pile embedding method includes a pre-boring method and a digging method. The pre-boring method is a method of excavating the ground using an auger with a drill bit fixed at the tip, forming a pre-made pile insertion hole in the ground, and then inserting the pre-made pile into the pre-made pile insertion hole. For this, as shown in FIG. 9 (a), a pile insertion hole 3 is formed using a drilling device such as an auger 2 with a drill bit 1 attached to the lower end, as shown in FIG. 9 (b). After placing concrete under pile 4 at the bottom, a method of inserting ready-made pile 5 into pile insertion hole 4 as shown in FIG. 9 (c), or a drill bit at the tip as shown in FIG. 10 (a) 1 is fixed, and the earth and sand in the ground is excavated by the excavation bit 1 using an excavation shaft 7 projecting many disturbing blades 6 on the outer periphery, and water is injected into the excavation earth and sand through the excavation shaft 7. Is disturbed by the disturbance blade 6 to form a pile insertion hole 9 filled with a columnar soft soil 8 in the ground. As shown in FIG. 10B, a hardener such as cement milk is injected and mixed into the soft soil 8 when the excavation shaft 7 is extracted, and after the excavation shaft 7 is extracted as shown in FIG. There is a method of sinking the ready-made pile 10 before the soft soil 8 containing the agent is cured.
[0003]
In the middle digging method, as shown in FIG. 11, a drilling auger 12 is used for the excavating shaft 11, and a drilling device having a drilling bit 13 fixed to the tip thereof is inserted into the ready-made pile 14. There is a method of leading the excavation bit 13 and press-fitting it into the ready-made pile 14 ground, and discharging excavated earth and sand by the excavation bit 13 to the ground by the auger 12.
[0004]
In each of the conventional methods described above, the excavated earth and sand are discharged when the ready-made piles are laid, and it is necessary to treat the discharged earth and sand. In recent years, as a method of solving such problems, a special metal fitting is attached to the tip of the pile and rotated together with the pile to push the earth and sand of the pile press-in part horizontally and press fit while forming a pile settling space. There is a soil settlement method.
[0005]
This construction method uses a propulsion head 23 in which a spiral blade 21 is integrally projected on the outer periphery of a bottomed cylindrical propulsion head body 20 as shown in FIG. By fixing this to the tip of the ready-made pile 24 and turning the propulsion head 23 together with the ready-made pile 23 in the screwing direction of the spiral blade 21, the screwing force of the spiral blade 21 in the ground disturbed by the excavating bit 22 By pushing the propulsion head 23, the ready-made pile 24 is submerged in the ground.
[0006]
[Problems to be solved by the invention]
Among the above-mentioned conventional methods, the pre-boring method and the middle digging method require a large amount of excavated soil to be discharged to the ground when piles are laid, which makes it necessary to treat the discharged sediment and make it difficult to secure the site. is there. In addition, the above-described rotary push-in type no-drainage sedimentation method does not discharge excavated soil, so it is less polluted than other methods in that it does not require sediment treatment, but the ground conditions are suitable for this method. There is a problem that it cannot be applied to the ground where the earth and sand cannot be displaced in the horizontal direction, such as in a dense clayey formation.
[0007]
For this reason, when carrying out the construction method, the state of the ground to be constructed is investigated by boring, etc., and it is confirmed that there is no unsuitable formation for this construction method until the required subsidence depth is reached. There is a problem that it requires time and cost for the previous geological survey.
[0008]
In view of the above-mentioned problems, the present invention can embed a pile without soil without requiring a prior geological survey, and when it reaches an unsuitable stratum, the same device can be used from that position. It was made for the purpose of providing a low-pollution and economical economical method for embedding piles that can be used for medium digging.
[0009]
[Means for Solving the Problems]
In order to solve the above-described conventional problems and achieve an intended object, the invention according to claim 1 is provided with a spiral blade integrally formed in a spiral arrangement around a central axis, and a plurality of excavation bits at a lower end. At a height position having a predetermined distance from the upper end of the spiral blade, and enters the inside of the outer periphery of the spiral blade during forward rotation in the direction in which soil is discharged by the spiral blade, It has an enlarged bit that protrudes in a radial direction by a predetermined length from the outer peripheral edge of the spiral blade during reverse rotation, and can be inserted into a hollow ready-made pile to be embedded in the outer diameter of the spiral blade and the enlarged The bit uses a drilling head with an enlarged bit whose tip protrudes outward from the outer periphery of the ready-made pile when protruding,
[0010]
The excavation head is fixed to the tip of the rotary spindle and inserted into the ready-made pile, the upper part of the spiral wing of the excavation head is inserted into the lower end of the ready-made pile, and the expansion bit is below the tip of the ready-made pile. In a certain state, the excavation head is rotated in the reverse direction to push the earth and sand and form a pile insertion hole while pushing the soil excavation head into the ground together with the ready-made pile, and the excavation head is rotated in the forward direction by the spiral blade. There is a ready-made pile embedding method characterized by embedding ready-made piles in the ground while switching and using the subsidence work of embedding piles while pumping up soil according to the ground conditions .
[0011]
By constructing in this way, when performing the sinking work of the ready-made pile with the excavation head in front of the tip of the ready-made pile, there is a ground that is not suitable for this in the middle of the pile sinking work with no soil Can use the same excavation head for subsidence work.
[0012]
On the contrary, when passing through the ground where pile subsidence by non-exhaust soil is possible in the middle of subsidence work by middle excavation in the ground where pile subsidence work by non-exhaust soil is inappropriate, switch to the work by non-exhaust soil. In any case, it is possible to carry out the sinking work of the ready-made piles with little soil removal.
[0013]
A feature of the invention according to claim 2 is that, in addition to the configuration of claim 1, the spiral inclination angle of the spiral blade is at least 10 to 30 ° with respect to a plane whose lower end portion is orthogonal to the central axis. is there. By configuring in this way, when the pile head is swung with no excavation by rotating the excavation head, the rise of sediment from between the spiral blades is suitably suppressed, and the expulsion without sedimentation is effectively performed. Is called.
[0014]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, the rotary support shaft is also used as a spiral auger for earthing, and the inclination angle of the spiral blade of the spiral auger is changed to the spiral of the excavation head with the expansion bit. It is to use something larger than the wing.
[0015]
The feature of the invention of claim 4 is that, in addition to the configuration of claim 2 or 3, the portion where the spiral blade inclination angle of the excavation head is 10 to 30 ° is projected out of the tip of the ready-made pile at the time of subsidence work. It is to operate in the state. By comprising in this way, the earth and sand are discharged | emitted smoothly at the time of Nakabori sedimentation work.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to FIGS.
[0017]
First, the excavation head with an expansion bit used in the method according to the present invention will be described. FIG. 1 shows a schematic configuration of the excavation head. The excavation head 40 includes a central shaft 41, a pair of spiral blades 42 integrally provided on the outer periphery of the central shaft, and an excavation fixed to the lower ends of the spiral blades 42. Bit 43 is provided. The upper end of the central shaft 41 is provided with a joint 41a that is fitted to and coupled to a joint 36c at the lower end of the rotary support shaft 36.
[0018]
Further, the excavation head 40 is provided with an enlarged bit 44 that protrudes further outward from the outer periphery of the spiral blade 42.
[0019]
A center hole 41b communicating with the center hole 36a of the rotation support shaft 36 is opened through the center of the center shaft 41, and a liquid agent discharge port is opened at the lower end thereof.
[0020]
The spiral blade 42 has a shape in which a steel strip is spirally wound around the outer periphery of the central shaft 41 with the width direction of the strip facing the radial direction, and the inclination angle in the spiral direction is not rotated. When pushed in, the angle with respect to the horizontal direction when the central axis is set upright, that is, the angle α with respect to the plane perpendicular to the central axis is about 10 to 30 ° so that the earth and sand do not easily move along the spiral. Is set to This angle may be increased as the lower end side of the spiral blade 42 is smaller and reaches the upper end side.
[0021]
The enlarged bit 44 is provided at a position symmetrical to each other about the central axis 41 and is rotatably supported by a pivotal metal fitting 45 having a U-shaped cross section. The pivotal support metal 45 is inserted into a portion where the outer peripheral edge of the spiral blade 42 is cut out toward the central axis, and is fixed integrally therewith. The base end portion of the enlarged bit 44 is inserted between the U-shaped parallel piece portions 45a and 45b of the pivot support metal 45, and the pivot shaft 46 is vertically penetrated through the parallel piece portions 45a and 45b and the enlarged bit 44. The enlarged bit 44 is supported so as to be rotatable about the pivot 46.
[0022]
The inner surface of the back piece 45c connecting the U-shaped parallel pieces 45a and 45b of the pivotal support 45 is provided with a stopper 47 when the enlarged bit 44 stands in the rotational radius direction of the excavation head 40. The enlarged bit 44 is tilted in the auger rotation circumferential direction at a position opposite to the stopper 47 by about 90 ° from the position where the side surface of the expansion bit 44 abuts against the stopper 47 and stands upright in the auger rotation radial direction. It can be freely rotated in the horizontal direction up to the position.
[0023]
Further, the pivot bracket 45 is rotated in the direction in which the excavation head 40 is pumped up, that is, in the direction in which the earth and sand is moved upward by the spiral blade 42 by rotating the auger excavation head 40. The rotation of the direction is forward rotation, and the rotation in the opposite direction is reverse rotation). The back piece 45c is fixed to the direction side, and therefore the excavation head 40 is rotated in the soil in the reverse direction. As shown in FIG. 3, the expansion bit 44 is moved to the protruding state position standing upright in the radial direction by the resistance of earth and sand, and the protruding side is maintained by contacting the back side in the rotational direction with the stopper 47.
[0024]
On the contrary, when the excavation head 40 is rotated forward in the soil, as shown in FIGS. 1 and 2, the enlarged bit 44 is tilted in the rotational circumferential direction by the resistance of the earth and sand, and falls to the center side from the spiral blade 42. It is designed to be turned to the stowed state.
[0025]
Next, an example of the ready-made pile embedding method according to the present invention , in which the excavation head is used and the ready-made pile is settled together with the excavation head, will be described.
[0026]
FIG. 4 shows an outline of a pile driving device used for the construction of this construction method. In the figure, reference numeral 30 denotes a device main body which can be moved by a traveling means consisting of a crawler, and a column 31 is erected at the end thereof. ing. A slide guide 32 is fixed to the column 31 in the axial direction, and a rotation driving means 33 and a pile insertion means 34 are supported on the support 31 so as to be movable in the vertical direction. These means are not shown in detail in the drawing, but are provided with slide drive means for moving them in the vertical direction.
[0027]
The rotation drive means 33 includes a rotation drive source 33a composed of an oil motor or an electric motor, and a rotation support shaft 36 is detachably connected to a drive shaft 35 that is rotated by the drive source 33a. The drive shaft 35 can change the rotation in the forward and reverse directions by switching the rotation direction by a rotation drive source . This rotation switching may be performed by a gear mechanism for rotation switching. As the rotary support shaft 36, a spiral auger for earthing provided integrally with a spiral blade on the outer periphery is used.
[0028]
The pile insertion means 34 is provided with a pile suspension device 37 that fixes and hangs the upper end of a prefabricated pile 50 such as a precast concrete pile at the lower end. This pile suspending device 37 suspends the ready-made pile 50 in a rotatable state.
[0029]
In this way, the ready-made pile 50 is moved in the settling direction by being moved downward by the slide driving means in a state where the ready-made pile 50 is suspended. In addition, as shown in FIGS. 5 and 6, the ready-made pile 50 is provided with an extended bit locking projection 51 constituting a co-rotating mechanism at the lower end and protruding in a contrasting position around the center of the pile. Is used. Moreover, what wound the steel band 52 to the height as high as a pile outer diameter around the lower end part outer periphery of the ready-made pile 50 is used.
[0030]
A hollow hole 36a serving as a flow path for passing a solidifying agent such as cement milk or water for jet spray water passes through the center of the rotating support shaft 36 that also serves as the central axis of the spiral auger for earthing. Has been. As shown in FIG. 5, the spiral blade of this spiral auger has a larger inclination angle than the spiral blade 42 than the excavation head 40.
[0031]
A state in which the pile driving device configured as described above is carried into the construction site, the support column 31 is erected at a predetermined ready-made pile pile embedding position, and the rotary spindle 31 and the excavation head 40 are connected in the ready-made pile 50. Insert with. Thereafter, the ready-made pile 50 and the rotation support shaft 31 are lifted by a winch, and the upper ends are fixed to the pile insertion means 34 and the rotation driving means 33, respectively, and are suspended.
[0032]
At this time, as shown in FIG. 5, the upper portion of the excavation head 40, that is, the upper portion of the spiral blade 42 is accommodated in the lower end portion of the ready-made pile 50, and the lower portion projects downward from the lower end of the ready-made pile 50. The relative positional relationship between the ready-made pile 50 and the excavation head 40 is adjusted so as to be positioned below the treetop from the lower end of the ready-made pile 50.
[0033]
In the excavation head 40, the outer diameter of the spiral blade 42 can be easily inserted into the ready-made pile 50, and the excavation head 40 is formed in such a size that earth and sand do not easily pass through the inner peripheral surface of the ready-made pile 50. In addition, the enlarged bit 44 protrudes 30 mm or more from the outside diameter of the ready-made pile 50 when standing upright in the radial direction described above, and is 10 mm or more inside from the inside diameter of the ready-made pile 50 when collapsed in the circumferential direction. Use the one whose length is selected so that
[0034]
In this state, the excavation head 40 is pushed into the ground 60 while the excavation head 40 is reversely rotated by the rotation driving means 33. If the ground 60 can be easily inserted into the ground 60 by its own weight, the ground 60 is lowered by its own weight. Further, when it is necessary to increase the fluidity of the earth and sand depending on the conditions of the ground 60, water injection for loosening the ground is performed through the inner cylinder 36 and the center hole 41b.
[0035]
At this time, since the excavation head 40 is opposite to the rotation in the earthing direction by the spiral blade 42, the earth and sand in the ground 60 is not earthed but is pushed away in the downward and horizontal directions. When the enlarged bit 44 is lowered to a position where it reaches the ground, the enlarged bit 44 is raised at the protruding position by the resistance of the earth and sand, as shown in FIG. 6, and disturbs the ground in a wider range than the outer periphery of the ready-made pile 50. And push it horizontally. In this way, under the lower end of the ready-made pile 50, the ground 60 is disturbed and loosened, and a leading hole 61 is formed in which a part of the earth and sand is pushed downward and laterally.
[0036]
In the leading hole 61 formed in this way, the ready-made pile 50 is lowered together with the lowering of the excavation head 40 and is sequentially settled in the ground. At this time, since the spiral direction angle of the spiral blade 42 is about 10 to 30 ° with respect to the horizontal, the lower end opening of the ready-made pile 50 is plugged by the excavation head 50, and the ready-made pile 50 is moved from the lower end. It settles in a state where earth and sand do not enter.
[0037]
In addition, when the enlarged bit 44 reaches the ground 60 and stands upright at the projecting position during the sinking, the enlarged bit 44 comes into contact with the enlarged bit locking projection 51 to co-rotate the ready-made pile 50. As a result, the ready-made pile 50 is turned, and the outer peripheral surface of the ready-made pile 50 and the earth and sand are cut off and settled in the ground.
[0038]
In addition, when the required settling depth of the ready-made pile 50 is shallow, or when the ready-made pile 50 can be easily settled without turning depending on the ground conditions, the ready-made pile 50 without using the enlarged bit locking protrusion 51 is used. use.
[0039]
In this way, the soil-free sedimentation operation is continued, and when the ground reaches the ground where it is difficult to perform the soil-free sedimentation operation, the rotation of the excavation head 40 is switched to the normal rotation. When the excavation head 40 is rotated forward, as shown in FIGS. 7 and 8, the enlarged bit 44 falls to the storage position due to the resistance of the earth and sand, the ground 60 is excavated by the excavation bit 43, and the excavated earth and sand is unloaded by the spiral blade 42. Then, the pile 50 is pushed up into the ready-made pile 50, and the ready-made pile 50 is press-fitted while pushing up the earth and sand by the spiral auger for excavation constituting the rotary support shaft 36, and is settled by subsidence work.
[0040]
At the time of this subsidence work, as shown in FIG. 7, the excavation head 40 is excavated and submerged in a state of being advanced from the lower end of the ready-made pile 50 to the vicinity of the upper end thereof. As a result, the excavated earth and sand are smoothly unearthed without being greatly affected by the presence of the enlarged bit 44 and the pivot metal fitting 45 for its attachment.
[0041]
As described above, according to the ground conditions in the middle of subsidence, the soil-free subsidence operation and the Nakabori subsidence operation are properly used to subsidize to the desired depth, and then the tip treatment under the pile is performed. For example, the tip treatment uses a striking method or a method in which a hardening agent such as cement milk is injected into the soil through the center hole 41b and only the excavation head 40 is lowered to mix and solidify the solidifying agent in the disturbed soil below the pile. .
[0042]
【The invention's effect】
As described above, the ready-made pile embedding method according to the present invention can form the pile insertion hole and the pile pushing method without soil without prior geological survey, and is unsuitable for work without soil. When it reaches the point, it is possible to carry out drilling work or excavation work from the position by using the same device, and it is possible to bury buried piles with low pollution and high economic efficiency.
[Brief description of the drawings]
FIG. 1 is a side view showing an excavation head used in the method of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
3 is a cross-sectional view showing a state in which the excavation head enlarged bit shown in FIG. 1 is raised. FIG.
FIG. 4 is a side view showing an outline of the entire apparatus used in a method for sinking a ready-made pile together with an excavation head in the present invention.
FIG. 5 is an enlarged cross-sectional view showing the excavation head at the lower end of the ready-made pile at the time of the soilless sedimentation work.
6 is a cross-sectional view taken along line BB in FIG.
7 is an enlarged cross-sectional view showing an enlarged bit storage state of the excavation head portion inserted into the lower end portion of the ready-made pile during the intermediate moat subsidence operation of the apparatus shown in FIG.
FIG. 8 is a cross-sectional view taken along the line CC in FIG.
FIG. 9 is a cross-sectional view schematically showing a process of an example of a conventional pre-boring method.
FIG. 10 is a cross-sectional view schematically showing another example process of the conventional pre-boring method.
FIG. 11 is a cross-sectional view schematically showing a process of an example of a conventional Nakahori method.
FIG. 12 is a cross-sectional view showing a conventional soil-free sedimentation method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 30 Apparatus main body 31 Support | pillar 32 Slide guide 33 Rotation drive means 33a Drive source 34 Pile insertion means 35 Drive shaft 36 Rotation support shaft 36a Hollow hole 36b Joint 37 Pile suspending device 40 Excavation head 41 Center axis 41a Joint 41b Center hole 42 Spiral blade 43 Excavation Bit 44 Expansion Bit 45 Pivot Bracket 45a, 45b Parallel Piece 45c Back Piece 46 Axis 47 Stopper 50 Ready-made Pile 51 Enlargement Bit Locking Projection 60 Ground 61 Leading Hole

Claims (4)

The spiral blade is integrally provided in a spiral arrangement around the central axis, and a plurality of excavation bits project from the lower end, and the spiral blade is located at a height position having a predetermined distance from the upper end of the spiral blade. And having an enlarged bit that enters inside the outer peripheral edge of the spiral blade during forward rotation in the direction in which the earth is discharged and protrudes in a radial direction by a predetermined length from the outer peripheral edge of the spiral blade during reverse rotation, The outer diameter of the wing can be inserted into a hollow ready-made pile to be embedded, and the enlarged bit uses a drilling head with an enlarged bit whose tip protrudes outward from the outer periphery of the ready-made pile,
The excavation head is fixed to the tip of the rotary spindle and inserted into the ready-made pile, the upper part of the spiral wing of the excavation head is inserted into the lower end of the ready-made pile, and the expansion bit is below the tip of the ready-made pile. In a certain state, the excavation head is rotated in the reverse direction to push the earth and sand and form a pile insertion hole while pushing the soil excavation head into the ground together with the ready-made pile, and the excavation head is rotated in the forward direction by the spiral blade. A prefabricated pile embedding method characterized by embedding prefabricated piles in the ground while switching and using the Nakabori subsidence work of embedding piles while pumping up soil . The ready-made pile embedding method according to claim 1, wherein a spiral inclination angle of the spiral blade is 10 to 30 ° with respect to a plane having at least a lower end portion orthogonal to the central axis . The ready-made pile embedding method according to claim 2 , wherein the rotary support shaft is also used as a spiral auger for earthing, and the inclination angle of the spiral blade of the spiral auger is larger than the spiral blade of the excavation head with the expansion bit . The ready-made pile embedding method according to claim 2 or 3 , wherein the intermediate drilling operation is performed in a state in which a portion of the excavation head with a spiral blade inclination angle of 10 to 30 ° is protruded outside the tip of the ready-made pile.

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