JP6230095B2 - Removal method of existing structure - Google Patents

Description

  The present invention relates to a method for removing an existing structure such as a pile buried in the ground.

  When an existing structure such as an existing pile buried underground is lifted to the ground and removed, the existing structure is There are many cases where it is virtually impossible to pull up as a whole.

  By the way, as a method of removing the existing structure in the ground, the casing is built while excavating the periphery of the existing structure with the casing, the existing structure inside the casing is crushed with a chisel or breaker, etc. For example, there is a method of finely fusing and dividing them with a hammer grab or the like. Here, when the existing structure is larger than the casing to be used, the above procedure is performed in a plurality of times. When such a removal method is performed under the limit of empty heads, for example, because the size of the hammer grab is limited, the deep foundation method is applied, or a large device is separately manufactured and the removal work is performed. However, both the case where the deep foundation method is applied and the case where the apparatus is manufactured separately cause the cost of the removal work to increase.

  Here, Patent Documents 1 and 2 can be cited as conventional techniques related to removal of an existing structure.

  Patent Document 1 discloses a technique for collecting and removing cast-in-place piles and steel pipe piles having a large diameter and a long pile length by applying an all casing method.

  Patent Document 2 discloses a method for removing a part of an existing pile and a lifting device for the removed part. More specifically, the existing pile is cut in the transverse direction at the lower end position of the site where the existing pile should be removed, the existing pile is divided into a withdrawal part and a remaining part, and only the withdrawal part is lifted upward and removed. is there.

  When the technique disclosed in Patent Document 1 is applied under the restriction of the empty head, the pile body is directly gripped by the chucking device through the spacer when the pile is lifted. There is a risk of peeling off and sliding off due to a decrease in frictional force.

  On the other hand, it can be understood that the technique disclosed in Patent Document 2 is suitable for the removal work of the existing structure under the empty head limitation. By the way, in this document, there is a description of removing an existing pile while taking a reaction force on a lump obtained by cutting the existing pile in the vertical direction when pulling up the extraction portion. However, a method for dealing with a case where there is no lump capable of taking a reaction force is unclear, and it must be said that the technique is insufficient in this respect. Furthermore, it is necessary to manufacture a removal device according to the removal object, and there is a concern that the removal work becomes expensive.

Japanese Patent Laid-Open No. 10-252065 JP 2004-1116020 A

  The present invention has been made in view of the above-mentioned problems, and it is not necessary to prepare a large-scale special device when removing an existing structure buried in the ground under the limitation of the sky head. It aims at providing the removal method of the existing structure which can remove an existing structure efficiently.

  In order to achieve the above object, the method for removing an existing structure according to the present invention attaches a tension member to the existing structure buried in the ground and uses an excavator to remove the existing structure and the surrounding ground. The first step of installing a casing between the existing structure and the ground to cut the edge of the ground, installing the gantry on the ground, and supporting the tension member with the gantry, and pulling the tension member upward, excavating the existing structure A part of the structure is pulled up to the ground so as to pass inside, a hole is drilled in the middle of the existing structure lifted to the ground, a support member is inserted into the hole, and the support member is fixed to fix the existing structure The second step of securing the fixed posture of the object and cutting and removing the upper part of the existing structure from the mounting position of the support member, a new top end surface of the existing structure generated by partial cutting of the existing structure In A tension member is attached, the tension member is supported by a gantry, the existing structure is lifted to the ground using an excavator, and a separate hole is drilled in the middle of the existing structure lifted to the ground. A third step of inserting a support member into the structure, securing the support member to secure a fixed posture of the existing structure, and cutting and removing a portion above the attachment position of the support member in the existing structure; The existing structure is removed by repeating the steps.

  The removal method of the present invention attaches a tensile member to an existing structure, pulls it up to the ground while pulling it, cuts and removes a part of the existing structure, and provides a hole in the middle of the existing structure to support it. By inserting a member and cutting the existing structure with this support member fixed in place on the ground, a stable posture can be obtained without sliding off the existing structure partially pulled up to the ground. One feature is that a part of the cutting can be executed.

  Here, “existing structure” means that in addition to cast-in-place piles buried in the ground, steel pile piles, pre-made piles such as PHC piles, etc., all piles are included, and buried underground Also included are concrete and steel caissons and foundations.

  When pulling up an existing structure, in order to cut the edge between this existing structure and the surrounding ground, a relatively short casing is sequentially pressed into the ground while using an excavator such as an all-casing excavator. To go. The reason why the short casing is added is to cope with the empty head limitation.

  In addition, when a part of an existing structure is first lifted to the ground, a stand is constructed on the ground to take a reaction force when the existing structure is lifted.

  This gantry can be constructed by assembling a steel material directly on an existing structure, and can be easily and inexpensively manufactured.

  In order to pull an existing structure, first, a hole is drilled to a predetermined depth of the existing structure using a boring drilling machine or the like on the top end surface of the existing structure, and a tensile member made of a reinforcing bar, PC steel, etc. Is inserted and filled with grout or the like to attach the tension member to the existing structure.

  Then, by attaching the upper end of the attached tension member to a center hole jack or the like installed on the gantry, preparation for the first lifting of the existing structure is completed (the first step).

  Next, the center hole jack or the like is operated, and the existing structure is pulled up to the ground so that the existing structure passes through the inside of the excavator in which the casing is press-fitted into the ground. Here, the reason that “the existing structure passes through the inside of the excavator” is that the existing structure is lifted later by using an excavator in which a casing is press-fitted or the like.

  When the upper end of the existing structure is pulled up to the top of the excavator, a hole is drilled in the middle of the existing structure at this stage, and a support member (so-called “steel”) such as a steel bar or square steel is made into the hole. The support member is inserted into the upper end of the casing.

  In a stable posture where the support member is supported by the casing, a cutting level is set above the support member mounting position (hole position) of the existing structure, and a part of the existing structure is obtained using a wire saw or the like at this cutting level. Cut off.

  The cut structure is preferably lifted and removed by a telescopic crane suitable for lifting work under the sky head limit (the second step).

  At the stage where the second step is completed, the top end surface of the existing structure is a cut surface, and the tensile member protruding upward from the top end surface of the existing structure is also cut before the cutting. Therefore, by exposing the head of the tension member embedded over the top end surface, attaching a coupler, etc. to this exposed location, and attaching a separate tension member to the coupler, the cut surface of the existing structure (new ceiling This separate tension member can be projected from the end face. And the edge part of this separate tension member is fixed to a mount, and preparation for the next cutting is performed.

  At this stage, since a part of the existing structure exists inside the excavator, it is now possible to lift the existing structure using the extension of the jack of the excavator.

  The jack of the excavator is extended to pull up the existing structure, and this lifting creates a space between the support member and the excavator. In this space, a steel or concrete spacer (block The support member can be temporarily supported by inserting the material.

  Extend the jack of the excavator to the maximum with the spacer temporarily supporting the existing structure, support the tension member fixed to the existing structure on the gantry, and shrink the excavator jack after the support to the gantry is completed Then, the spacer is added again in the space formed between the excavator and the support member, the jack is extended again, and the existing structure is further pulled up. Then, when the existing structure is pulled up to the planned cutting position, the spacer is removed, and in the same way as in the second step, a separate hole is drilled in the middle position of the existing structure, and a separate support member is inserted into this separate hole, This separate support member is fixed to the upper end of the casing.

  And an upper part is cut | disconnected from the attachment location of the separate support member in an existing structure, This is removed (above, 3rd step).

  Removal of all existing structures is completed by sequentially repeating this third step.

  When the existing structure is completely removed from the ground, it is better to refill the cavity formed in the ground after the removal.

  Here, a pipe that is in fluid communication from the lower end of the casing to the ground may be provided in the thickness of the casing, and pressure fluid may be provided from the ground to the lower end of the casing when the existing structure is pulled out. An upward push-up force is applied to the lower surface of the existing structure by the provided pressure fluid, and the pull-up force of the existing structure is improved by the push-up force.

  As can be understood from the above description, according to the method for removing an existing structure of the present invention, an existing structure can be removed even when the existing structure is removed without the need to prepare a large-scale special device even when the existing structure is removed. It is possible to remove the existing structure safely and efficiently, and remove it while supporting it stably.

It is the flowchart explaining embodiment of the removal method of the existing structure of this invention. It is the flowchart explaining embodiment of the removal method following FIG. FIG. 3 is a flowchart illustrating an embodiment of a removal method following FIG. 2. It is the flowchart explaining embodiment of the removal method following FIG. It is the flowchart explaining embodiment of the removal method following FIG. It is the flowchart explaining embodiment of the removal method following FIG. FIG. 7 is a flowchart illustrating an embodiment of the removal method following FIG. 6. It is the flowchart explaining embodiment of the removal method following FIG. (A) is the flowchart explaining embodiment of the removal method following FIG. 8, (b) is the figure which looked at the supporting member arrange | positioned in the hole for supporting members from the top. FIG. 10 is a flowchart illustrating an embodiment of the removal method following FIG. 9. It is the flowchart explaining embodiment of the removal method following FIG. FIG. 12 is a flowchart illustrating an embodiment of the removal method following FIG. 11. FIG. 13 is a flowchart illustrating an embodiment of the removal method following FIG. 12. It is the flowchart explaining embodiment of the removal method following FIG. It is the flowchart explaining embodiment of the removal method following FIG.

  Hereinafter, an embodiment of a method for removing an existing structure of the present invention will be described with reference to the drawings.

(Embodiment of method for removing existing structure)
FIGS. 1-15 is the flowchart explaining embodiment of the removal method of the existing structure of this invention in the order.

  In the illustrated example, as shown in FIG. 1, a method for removing a pile P, which is an existing structure, in the underground G under a sky head restriction, is described. In addition, in each figure, illustration of the ground structure which becomes the grounds of the sky head restriction in the ground space above the pile P is omitted, but in the ground space above the pile P, buildings, railway lines, railway station buildings It is assumed that the above ground structure exists and the removal work must be carried out in a narrow space.

  As shown in FIG. 1, when removing the pile P buried in the underground G, first, the ground is excavated to expose the top end of the pile P, and the boring drill M1 is fixed to the top end. The hole H1 for a tensile member is drilled to a predetermined depth of the pile P with this drilling machine M1.

  After the predetermined number of tensile member holes H1 having a predetermined depth are drilled, next, as shown in FIG. 2, a tensile member B such as a reinforcing bar or PC steel material is disposed here, and a grout or the like is placed in the tensile member hole H1. A predetermined number of tensile members B are projected from the top end surface of the pile P by filling and curing the filler F. In addition, the embedment length of the tension member B in the pile P is pulled out of the pile P by the circumferential frictional force between the tension member B and the pile P when the tension member B is pulled to pull the pile P to the ground. The length is set so that the pile P can be pulled up as desired.

  If the tension member B is installed in the pile P, the top end of the pile will be backfilled. Next, as shown in FIG. 3, a guide iron plate (not shown) is arranged around the ground of the pile P, and the all casing excavator M <b> 2 is self-propelled by a covering band provided on the pile P on the guide iron plate. install.

  Here, prior to the pulling out of the pile P, first, the edge of the pile P and the surrounding ground G is cut, and the all casing excavator M2 is used to facilitate the pulling out of the pile P. Perform press-fitting.

  Specifically, as shown in FIG. 4, the casing C is lifted by a telescopic crane M3 suitable for lifting work under a sky head restriction and disposed inside the excavator M2. Here, as a method for press-fitting the casing C, a method is adopted in which the casing C, which has a relatively short length in consideration of the head limitation, is sequentially press-fitted into the ground and added. In press-fitting the casing C, it is preferable to attach a water supply head (not shown) to the casing C and perform rotary press-fitting while feeding water inside.

  As shown in FIG. 5, a casing having a predetermined length is constructed between the pile P and the surrounding ground G by press-fitting and sequentially adding the casings C. Edge cutting with the surrounding ground G is performed. At the time when the press-fitting of the casing C is completed, the casing C is sufficiently rotated while circulating fresh water to reduce the rotational resistance.

  Next, as shown in FIG. 6, a steel material is assembled so as to surround the excavator M2, and a temporary mount T is constructed.

  Then, the same number of center hole jacks J as the tension members B are fixed to the uppermost horizontal member constituting the frame T, and the ends of the tension members B corresponding to the respective center hole jacks J are fixed.

  The above is the 1st step of the removal method of the existing structure of the present invention, and the preparation for drawing out pile P which is the existing structure is completed in this 1st step.

  Next, as shown in FIG. 7, each center hole jack J is operated synchronously, and the pile P is pulled up to a predetermined length on the ground so as to pass through the inside of the excavator M2.

  For example, if the pile P is pulled up to the vicinity of the horizontal member at the uppermost part of the gantry T as shown in FIG. 7, then, as shown in FIG. 8, an arbitrary portion between the top end surface of the pile P and the excavator M2 The position is set to the cutting line L, and a predetermined number of support member holes H2 are drilled below the cutting line L. The cutting level L is set based on the relationship between the size of the cut body to be cut and removed and the surrounding obstacles, the physique of the crane that lifts the cut body, and the like.

  For example, when two support member holes H2 are drilled as shown in the illustrated example, each support member hole H2 has a support member K made of a steel rod, square steel, or the like as shown in FIG. 9a. Is inserted, and the end of the support member K is projected from the pile P as shown in FIG.

  As shown in the figure, when the support member K is inserted and fixed in the support member hole H2, the end of the support member K is supported by the top end of the casing C, thereby securing the fixed posture before cutting the pile P. To do.

  Thus, after arrange | positioning the supporting member K to the pile P and ensuring the fixed attitude | position of the pile P, the pile P is cut | disconnected by the cutting level L with cutting tools, such as a wire saw.

  The cut body P ′ thus cut is lifted by a telescopic crane M3 as shown in FIG. 10, and is cut and temporarily placed in a yard, or directly carried to a transport truck and carried out of the field.

  The above is the 2nd step of the removal method of the existing structure of the present invention, and the first partial removal of pile P which is an existing structure is completed in this 2nd step.

  In the second step, the first cut and removal of the pile P is performed, so that the tensile member B is also cut at the cut surface of the pile P, and there is no tensile member protruding from the cut surface.

  Therefore, the top end surface of the pile P is buried with a breaker or the like so that the tension member embedded in the inside of the pile P and a separate tension member can be connected to enable lifting from above the pile P. The head of the tension member B is exposed, and the exposed head is equipped with a coupler. As shown in FIG. 11, a separate tension member B ′ is attached to the coupler, and the end of the tension member B ′ is attached to the mount T. Fix to the top horizontal member via a nut.

  At this stage, the support member K is supported on the base T1 installed on the stage of the excavator M2.

  In this state, the pile P penetrating the inside of the excavator M2 is gripped by the excavator M2, and therefore the pile P can be pulled upward by extending the jack of the excavator M2. That is, the subsequent extraction of the pile P is performed by using the excavator M2 applied when the casing C is press-fitted.

  When the jack of the excavator M2 is extended to a predetermined length, the separate tension member B 'that is nut-fixed by the horizontal member of the gantry T is loosened by the extension of the jack. Therefore, the tension member B 'is tensioned and the nut is retightened, whereby the pile P pulled up with the extension of the jack is supported on the mount T.

  Next, as shown in FIG. 12, as the excavator M2 is jacked up, a plurality of stages of spacers S are interposed in the space formed between the pedestal T1 that directly supports the support member K and the excavator M2. The member K is temporarily supported by the excavator M2 via the base T1 and the spacer S. More specifically, while the pile P is temporarily supported by the spacer S, the jack of the excavator M2 is extended to the maximum, and a separate tensile member B ′ fixed to the pile P is supported by the gantry T. After the support of the excavator M2 is completed, the jack of the excavator M2 is shrunk, the spacer S is added again in the space formed between the excavator M2 and the support member K, the jack is extended again, and the pile P is further pulled up.

  In this process, the nut of the separate tension member B ′ is appropriately retightened. As shown in FIG. 13, when the pile P is pulled up to the planned cutting position, the pedestal T1 and the spacer are supported with the pedestal T supported by the pile P. S is removed, and a separate support member hole H2 is drilled at a position below the set cutting line L.

  When the two support member holes H2 are drilled as shown in the illustrated example, the support members K are inserted into the respective support member holes H2 as shown in FIG. Let it protrude from

  As shown in the figure, when the support member K is inserted and fixed in the support member hole H2, the end of the support member K is supported by the top end of the casing C, thereby ensuring a stable posture before cutting the pile P. To do.

  Thus, after arrange | positioning the supporting member K to the pile P and ensuring the fixed attitude | position of the pile P, the pile P is cut | disconnected by the cutting level L with cutting tools, such as a wire saw.

  The cut body P ′ thus cut is lifted by the telescopic crane M3, temporarily placed in the yard or carried into the transport truck, and carried out of the field.

  The above is a 3rd step of the removal method of the existing structure of this invention, and the 2nd cutting removal of the pile P which is an existing structure is completed in this 3rd step.

  In the method for removing an existing structure of the present invention, the pile P can be completely removed from the ground G by sequentially repeating the third step.

  When the pile P is completely removed from the underground G, as shown in FIG. 15, the fluidized soil U is placed in the cavity formed in the extraction trace of the pile P to perform backfilling.

  As mentioned above, according to the removal method of the existing structure of the present invention shown in the figure, when the existing structure is sequentially lifted to the ground, and a part thereof is cut and removed, the supporting member is attached to the existing structure lifted to the ground. By fixing and fixing this support member, a part of the existing structure is cut and removed while securing the fixed posture, so efficient removal work is ensured while ensuring safety during removal work. Can be realized.

  In addition, it is possible to remove existing structures by using an all-casing excavator, installing a simple base, lifting and turning with a telescopic crane, etc., so there is no need to manufacture special equipment or mechanisms for this removal work. It is possible to remove the existing structure at a site where the overhead is restricted at low cost.

  Although not shown in the drawings, when the existing structure is pulled up, a pipe is provided in the wall thickness of the casing for fluid communication from the lower end of the casing to the ground, and when the existing structure is pulled out, the lower end of the casing is removed from the ground. A pressure fluid may be provided. An upward push-up force can be applied to the lower surface of the existing structure by the provided pressure fluid, and the liftability of the existing structure can be improved by the push-up force.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  M1 ... boring drilling machine, M2 ... excavator (all casing excavator), M3 ... crane truck (telescopic crane), C ... casing, P ... existing structure (pile), P '... cutting body, H1 ... tensile member Hole, F ... filler, B ... tension member, B '... separate tension member, G ... underground (ground), T ... mount, J ... center hole jack, L ... cutting level, H2 ... hole for support member , K: Support member (Kanzashi), U ... Fluidized soil

Claims (5)

Attach a tension member to an existing structure buried in the ground, and install a casing between the existing structure and the surrounding ground using an excavator to cut the edge of the existing structure and the ground. A first step of installing a cradle and supporting the tension member on the cradle;
By pulling up the tension member upward, a part of the existing structure is made to pass through the inside of the excavator, and a part thereof is pulled up to the ground, and a hole is drilled in the middle of the existing structure pulled up to the ground. A second step of inserting the support member, securing the support member to secure the fixing posture of the existing structure, and cutting and removing the upper part of the existing structure from the attachment position of the support member;
Expose the head of the tension member embedded over the new top end surface of the existing structure generated by partial cutting of the existing structure , attach a coupler to this exposed location, and attach a separate tension member to this coupler. Attach and support a separate tension member with a gantry, use an excavator to lift the existing structure to the ground, drill a separate hole in the middle of the existing structure lifted to the ground, A third step of inserting the support member, securing the support member to secure the fixed posture of the existing structure, and cutting and removing the upper part of the existing structure from the attachment position of the support member;
A method for removing an existing structure in which the third step is repeated to remove the existing structure.   2. The method for removing an existing structure according to claim 1, wherein in the second step, the tension member is attached to a center hole jack fixed to a gantry and the tension member is pulled up by the center hole jack.   The existing step according to claim 1 or 2, wherein in the third step, the excavator is jacked up to pull up the existing structure while the excavator supports the support member attached to the existing structure inside the excavator. How to remove the structure.   After jacking up the excavator and pulling up the existing structure, the existing structure is temporarily supported by interposing a spacer in the space formed between the top end of the casing and the support member. The method for removing an existing structure according to claim 3, wherein after the support is supported on the gantry via the tension member, the spacer is removed and a separate hole is drilled at an intermediate position of the existing structure.   Piping that is in fluid communication from the lower end of the casing to the ground is provided in the wall thickness of the casing, and when the existing structure is pulled out, the pressure fluid is provided from the ground to the lower end of the casing, and the existing structure is provided by the provided pressure fluid. The removal method of the existing structure in any one of Claims 1-4 which gives upward pushing force to the lower surface of a thing.

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