JP2017002675A - Foundation pile construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foundation pile construction method capable of installing a pile by a compact construction machine at low cost and constructing a foundation pile with sufficient resistance.SOLUTION: First, in a penetration process, a casing pipe 8 and an auger rod 7 are integrally rotated and penetrated in the ground in a state where the auger rod is inserted in the cylindrical casing pipe with the spiral blade 17 formed on an outer peripheral surface of the casing pipe. Next, the auger rod 7 is pulled out while the casing pipe 8 remains in the ground. At this time, cement milk is injected from a tip of the auger rod 7, or the cement milk is injected in the casing pipe 8 after pulling out the auger rod 7. A pile is inserted in the casing pipe 8 and installed. Finally, the casing pipe 8 is reversely rotated and pulled out of the ground. When the cement milk solidifies and is integrated with the pile, a foundation pile can be obtained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for constructing a foundation pile as a foundation of a building.

  Buildings such as houses are built on the foundation provided on the ground. Although there are various types of foundations, so-called foundation piles based on piles driven into the ground are excellent because they can construct a foundation with sufficient resistance even if the ground is soft. There is also a so-called cast-in-place concrete pile that is formed by drilling a borehole in the ground with an auger etc. and pouring concrete into this borehole, but in relatively small buildings such as houses, It is often composed of so-called ready-made piles, such as concrete piles and steel piles, which are driven into the ground. In such a ready-made pile, an auger drive device to which an auger screw is attached is set on a construction machine, and the auger screw is rotated by the auger drive device to punch a pile hole in the ground and driven into the pile hole. In driving piles, a method of injecting cement milk as a rooting liquid before driving may be carried out. In this method, when a hole is drilled in the ground with an auger screw, a predetermined amount of cement milk is injected from the tip of the auger screw, and then the auger screw is pulled out of the ground. A pile is driven into the pile hole into which the cement milk has been injected. This will solidify the cement milk and solidify the pile.

JP 2012-140787 A

  By the way, when driving a pile with a construction machine, the construction machine is lifted by the reaction force from the ground and becomes unstable. Therefore, the so-called press-fit, in which a predetermined member of the construction machine is connected to several other piles that have already been driven in and a new pile is driven in while preventing the lifting of the construction machine using the pull-out resistance of these piles. The construction method is also well known. Patent Document 1 describes a pile driving method applying the principle of the press-fitting method. In the construction method described in Patent Document 1, a predetermined casing pipe is used. This casing pipe is made of a steel pipe in which an auger screw is housed, and a spiral reaction force blade is formed on the outer peripheral surface thereof. The construction method described in Patent Document 1 is performed as follows. First, an auger screw is inserted into the casing pipe, and these are locked by a predetermined locking mechanism. The casing pipe and the auger screw integrated in this way are attached to the auger drive device and set on the construction machine. The auger drive device is driven and the ground is mined by the casing pipe and the auger screw so that only the uppermost part of the casing pipe is on the ground. Release the locking mechanism and remove the auger screw from the casing pipe. Then, the casing pipe is left in the ground. Insert the pile into the casing pipe. The pile is driven by a construction machine. At this time, a predetermined member of the construction machine is fixed to the uppermost part of the casing pipe. Since the casing pipe receives a large pulling resistance from the ground by the reaction force blade, the pile is driven into the ground to a predetermined depth while preventing the construction machine from being lifted using this pulling resistance. When the driving of the pile is completed, reverse the casing pipe and pull it out from the ground.

  As in the conventional method, drilling a pile hole with an auger screw and driving the pile, or injecting cement milk and then driving the pile to solidify the pile, patent documents Even if the pile is driven in as in the construction method described in 1, it is excellent that the pile can be driven into the ground appropriately. However, there are also problems to be solved. That is, in each of these methods, there is a problem in that when the pile is driven, it must be driven until the tip of the pile reaches a stable hard ground. When piles are driven into the ground, they are unlikely to sink by themselves, but because they are formed in columns, the frictional resistance is not always sufficient, and sufficient strength cannot be ensured for heavy buildings. The pile must therefore be driven until its tip reaches a stable, hard ground. However, the stable hard ground may be deep depending on the construction site, and in such a case, a large construction machine is required to drive the pile deeply. That is, the cost increases. Depending on the construction site, a large construction machine requiring a space may not be used, and in such a case, pile driving becomes difficult.

  The present invention has been made in view of the above-described problems. Specifically, the pile can be driven even with a small construction machine, and therefore, the foundation pile having a low cost and sufficient resistance can be obtained. It aims at providing the construction method of the foundation pile which can be constructed.

  In order to achieve the above object, the present invention is configured as a construction method in which a pile is driven into the ground and a foundation pile is constructed. First, as a penetration process, the casing pipe and the auger rod are integrally rotated to penetrate into the ground in a state where the auger rod is inserted into a cylindrical casing pipe having spiral blades formed on the outer peripheral surface. Next, the auger rod is pulled out leaving the casing pipe on the ground. Cement milk is poured into the casing pipe remaining on the ground. Cement milk may be injected from the tip of the auger rod when it is pulled out. Insert a pile into the casing pipe and drive it. Finally, reverse the casing pipe and pull it out of the ground. When the cement milk is solidified and integrated with the pile, the foundation pile is completed.

That is, the invention described in claim 1 is a construction method in which a foundation pile is constructed by driving a pile into the ground using an auger rod and a cylindrical casing pipe having a spiral blade formed on the outer peripheral surface. In the construction method, in the state where the auger rod is inserted into the casing pipe, the casing pipe and the auger rod are integrally rotated to penetrate into the ground, and the casing pipe is grounded. An auger rod pulling process for pulling out the auger rod, a water curable filler injecting process for injecting a water curable filler such as cement milk into the casing pipe, and a pile inserted into the casing pipe. It consists of a pile driving process for driving and a casing pipe pulling process for reversely rotating the casing pipe and pulling it from the ground. Configured as construction method for foundation piles characterized.
According to a second aspect of the present invention, in the construction method according to the first aspect, the water curable filler is substantially injected from the tip of the auger rod so that the auger rod drawing step and the water are substantially performed. It is constructed as a foundation pile construction method characterized by carrying out the curable filler injection step at the same time.
Invention of Claim 3 is comprised as the construction method of the foundation pile characterized by the said construction method of Claim 1, wherein the said water-hardening filler injection | pouring process is implemented after the said pile driving process. The
The invention according to claim 4 is the construction method according to any one of claims 1 to 3, wherein the water curable filling is performed in parallel with the casing pipe drawing step or after the casing pipe drawing step. It is constructed as a foundation pile construction method characterized by carrying out a water curable filler replenishment step of replenishing material.
According to a fifth aspect of the present invention, in the construction method according to any one of the first to fourth aspects, the pile driving step is performed by press-fitting the pile using the weight of a construction machine. It is constructed as a foundation pile construction method characterized by this.

  As described above, the present invention is a construction method for constructing a foundation pile by driving a pile into the ground using an auger rod and a cylindrical casing pipe in which spiral blades are formed on the outer peripheral surface. The construction method includes an intrusion step in which the auger rod is inserted into the casing pipe and the casing pipe and the auger rod are integrally rotated to penetrate the ground, and the auger rod is pulled out while leaving the casing pipe on the ground. The rod drawing process, the water curable filler injection process for injecting a water curable filler such as cement milk into the casing pipe, the pile driving process for inserting and driving the pile into the casing pipe, and the casing pipe are reversed. It comprises a casing pipe drawing process that rotates and pulls out from the ground. The water curable filler injected in the water curable filler injection process flows into the gap formed by the casing pipe drawing process, that is, the space occupied by the casing pipe. In the casing pipe drawing process, the casing pipe is pulled out by rotating in the reverse direction, so that it is drawn in a state where the shape of the spiral blade is maintained in the ground, and the water curable filler flows into such a space. The water-curable filler eventually solidifies integrally with the piles that have been driven in, but then the solidified water-curable filler, i.e., the cured body, has a cylindrical shape with a predetermined thickness and spiral blades on its outer peripheral surface. Will be formed. As a result, the pile is provided with a cylindrical portion within a predetermined range, and spiral blades are formed on the outer peripheral surface. The following resistance acts between the foundation pile and the ground. That is, the frictional force between the pile and the ground in the vicinity of the tip of the pile, the proof stress at the tip of the pile, and the frictional force of the columnar hardened body in which spiral blades are formed on the outer peripheral surface. The frictional force of the hardened body is very large because the spiral blade becomes a peripheral surface resistance in the ground, and thereby a large resistance force is obtained. Such multiple resistance forces will stabilize the foundation pile, ensuring that the foundation pile will have a large vertical support force even when the tip of the pile has not reached a stable, hard ground. Even a heavy building can be supported stably. In the construction method of the present invention, it is not always necessary to drive the pile deeply in the pile driving process, and an effect that construction is possible even with a small construction machine is obtained. According to another invention, the water curable filler is injected from the tip of the auger rod, and the auger rod pulling process and the water curable filler injecting process are substantially performed at the same time. Yes. If it does so, it can construct efficiently. According to another invention, it is configured to perform a water curable filler replenishing step in which water curable filler is replenished in parallel with the casing pipe pulling step or after the casing pipe pulling step. Yes. When the casing pipe is pulled out from the ground, the liquid level of the water-curable filler decreases, but this can be replenished. This gives a high quality foundation pile. According to still another invention, the pile driving process is performed by press-fitting the pile using the weight of the construction machine that drives the pile. If it does so, the problem that the problem of a noise and a vibration does not generate | occur | produce easily in a pile driving process, and the influence which has on the surrounding environment is also acquired.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the construction machine which concerns on embodiment of this invention, The (a) is a front view of a construction machine, The (a) is a perspective view of a casing pipe, The (c) is a perspective view of an auger rod. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the construction method of the foundation pile which concerns on embodiment of this invention, The (a)-(d) is front sectional drawing of the casing pipe, an auger rod, and a pile in each process. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the construction method of the foundation pile which concerns on embodiment of this invention, The (a)-(d) is front sectional drawing of the casing pipe, an auger rod, and a pile in each process. It is a perspective view of the casing pipe and auger rod which concern on other embodiment of this invention.

  Embodiments of the present invention will be described below. As shown in FIG. 1A, the construction machine 1 according to the present embodiment is a relatively small construction machine. That is, it is composed of a vehicle 2 that is self-propelled, a reader 4 provided on the vehicle 2, an auger drive device 5 that is guided by the reader 4 and slides. Although the reader 4 is only shown in a simplified manner in FIG. 1, the reader 4 is supported at three points by a predetermined member provided in the vehicle 2 and is set up vertically and accurately and stably. Yes. Accordingly, the auger drive device 5 also slides vertically and vertically with high accuracy and stability.

  In the present embodiment, the excavating body for excavating the ground includes not only the so-called auger rod 7 but also the auger rod 7 and the casing pipe 8. The auger rod 7 can also be referred to as a drilling rod, and is configured as is conventionally known. That is, as shown in FIG. 1 (c), it is composed of a predetermined rod body 10, and the rod body 10 is provided with bits 12 and 12 so that the ground can be easily excavated. Yes. In the present embodiment, the auger rod 7 has an engagement hole 13 formed in the upper part thereof. This is a hole for allowing the casing pipe 8 to be integrally locked as described below, but if the auger rod 7 and the casing pipe 8 can be fixed integrally by other means, the engagement hole 13 is essential. is not.

  The casing pipe 8 according to the present embodiment will be described. The casing pipe 8 is made of a steel pipe, and includes a cylindrical body 15 having a predetermined length and a spiral blade 17 formed on the outer peripheral surface of the cylindrical body 15. The inner diameter of the cylindrical body 15 is slightly larger than the outer diameter of the auger rod 7 so that the auger rod 7 can be inserted smoothly. The spiral blade 17 of the casing pipe 8 is a single helix in the present embodiment. Bits 18 and 18 are provided at the front end of the casing pipe 8 so that the ground can be easily excavated. In the present embodiment, an annular frame 20 is fixed to the upper portion of the casing pipe 8, and an engagement hole 21 is opened in the frame 20. Therefore, when the auger rod 7 is inserted into the casing pipe 8 and the engagement holes 13 and 21 are aligned, and a lock pin (not shown) is inserted, the casing pipe 8 and the auger rod 7 are integrated. Will be locked.

  The construction method of the foundation pile which concerns on this Embodiment is demonstrated. The construction machine 1 is carried into the place where the foundation pile is to be constructed, and the leader 4 is set up vertically. The auger rod 7 is inserted into the casing pipe 8, and these are fixed integrally and attached to the auger drive device 5. This state is shown in FIG. The casing pipe 8 and the auger rod 7 are supported vertically. The auger drive unit 5 is driven and slowly slides downward. That is, the penetration process is performed. Then, the casing pipe 8 and the auger rod 7 rotate integrally, and the spiral blade 17 of the casing pipe 8 penetrates smoothly as a whole while meshing with the ground. As shown in FIG. 2A, when the casing pipe 8 and the auger rod 7 have sufficiently penetrated into the ground and the uppermost portion of the casing pipe 8 remains on the ground, the penetration process is terminated. The locked state of the casing pipe 8 and the auger rod 7 is released, and the auger drive device 5 is slid upward as shown in FIG. That is, an auger rod drawing process is performed. When the auger rod pulling-out process is completed, the casing pipe 8 penetrates into the ground, and the casing pipe 8 has almost no earth and sand.

  As shown in FIG. 2D, a water curable filler injection step of injecting the water curable filler 26 into the casing pipe 8 is performed. The water curable filler 26 is mainly a water curable cured material made from cement such as cement milk or mortar, but a water curable cured material made from blast furnace slag can also be used. In this step, the water curable filler 26 is filled by a predetermined amount. In the present embodiment, the water curable filler injecting step is performed after completion of the auger rod drawing step, but these can also be performed in parallel. That is, if the water curable filler 26 can be discharged from the tip of the auger rod 7, the water curable filler 25 can be filled into the casing pipe 8 while the auger rod 7 is pulled out.

  Next, as shown in FIG. 3A, the press-fit shaft 25 is attached to the auger drive device 5, and a ready-made pile 24 such as a wooden pile, a concrete pile, or a steel pile is attached to the press-fit shaft 25. . The auger drive device 5 is slid to insert the pile 24 into the casing pipe 8. Then, as shown in FIG. 3A, the press-fit shaft 25 is driven to press-fit the pile 24 by its own weight. In this way, the pile driving process is performed, and the pile 24 is driven to a predetermined depth. In the present embodiment, the diameter of the pile 24 is slightly smaller than the inner diameter of the casing pipe 8. Therefore, the pile 24 is driven vertically with high accuracy without shifting the core. When the pile driving process is completed, the casing pipe drawing process is performed. That is, the tip of the press-fit shaft 25 is locked to the casing pipe 8 as shown in FIG. Then, the auger drive device 5 is driven to pull out the casing pipe 8 while rotating it in the reverse direction. When the casing pipe 8 is rotated and pulled out, the pulling speed is adjusted so that the casing pipe 8 moves upward by one pitch of the spiral blade 17 during one rotation. If it does so, the spiral trace of the spiral blade | wing 17 currently formed in the ground will not collapse. When the casing pipe 8 is pulled out, the water curable filler 26 flows and fills the spiral marks formed on the ground. Since the water-curable filler 26 is injected first, it can be quickly filled into the voids formed in the ground, and the soil can be prevented from being mixed into the water-curable filler 26. As the drawing of the casing pipe 8 proceeds, the liquid level of the water curable filler 26 decreases, so that a water curable filler replenishing step for replenishing the water curable filler as necessary is performed. The state where the casing pipe 8 is completely pulled out is shown in FIG. When the water-curable filler 26 is solidified and integrated with the pile 24, a foundation pile having a cured body having spiral blades formed on the outer peripheral surface is obtained. That is, a foundation pile with excellent vertical bearing capacity can be obtained.

  The foundation pile construction method according to the present embodiment can be variously modified. For example, the casing pipe 8 and the auger rod 7 to be used can be deformed. FIG. 4 shows a casing pipe 8 ′ and an auger rod 7 ′ according to the second embodiment. In this embodiment, the auger rod 7 ′ is provided with a spiral blade 11 on the outer peripheral surface thereof. ing. The spiral blade 11 has a double helix, that is, a double flight. The casing pipe 8 'has a slightly larger inner diameter so that such an auger rod 7' can be inserted. In the casing pipe 8 ′ according to this embodiment, the spiral blade 17 ′ is provided from the center to the lower end portion, and is not provided in the vicinity of the upper end portion. The foundation pile construction method according to the present embodiment can also be implemented by such casing pipe 8 'and auger rod 7'. The spiral blade 17 ′ may be provided only at the tip of the casing pipe 8 ′, and the shape may be variously modified. For example, a double flight may be used. In the casing pipe 8 ', the bits 18, 18,... Are not essential, and the casing pipe 8' without these can be implemented.

  The foundation pile construction method according to the present embodiment can be modified in other ways. For example, in the construction machine 1 according to the present embodiment, the auger rod 7 is detachable from the auger driving device 5, but it is not necessarily required to be detachable. It is sufficient that the auger rod 7 does not interfere with the driving of the pile in the pile driving process. For example, if the auger rod 7 penetrates the auger driving device 5 and retreats above the auger driving device 5, the pile driving can be performed without any problem. Is possible. In this embodiment, the pile 24 is attached to the tip thereof using the press-fit shaft 25 in the pile driving process, but the pile 24 may be attached to the tip of the auger rod 7. In this case, the press-fit shaft 25 becomes unnecessary. It is also possible to replace the process. In the present embodiment, the pile driving process is performed after the water curable filler is injected into the casing pipe 8, but the water curable filler is injected after the pile driving process is performed. A water curable filler injecting step may be performed.

DESCRIPTION OF SYMBOLS 1 Construction machine 2 Vehicle 4 Leader 5 Auger drive device 7 Auger rod 8 Casing pipe 10 Rod body 11 Spiral blade 12 Bit 13 Engagement hole 15 Cylindrical body 17 Spiral blade 18 Bit 21 Engagement hole 24 Pile 25 Press-fit shaft 26 Water hardening Filler

Claims (5)

Using an auger rod and a cylindrical casing pipe with spiral blades formed on the outer peripheral surface, a construction method for driving a pile into the ground and constructing a foundation pile,
The construction method is a state in which the auger rod is inserted into the casing pipe, and the casing pipe and the auger rod are integrally rotated to penetrate into the ground.
An auger rod pulling process for pulling out the auger rod leaving the casing pipe on the ground;
A water curable filler injection step of injecting a water curable filler such as cement milk into the casing pipe;
A pile driving process for inserting and driving a pile into the casing pipe;
A method for constructing a foundation pile, comprising: a casing pipe pulling step in which the casing pipe is reversely rotated and pulled out from the ground.   The construction method according to claim 1, wherein the water curable filler is injected from a tip of the auger rod, and substantially includes the auger rod drawing step and the water curable filler injection step. A foundation pile construction method characterized by being carried out simultaneously.   The construction method according to claim 1, wherein the water curable filler injecting step is performed after the pile driving step.   The construction method according to any one of claims 1 to 3, wherein the water curable filler is injected in a supplementary manner in parallel with the casing pipe drawing step or after the casing pipe drawing step. A method for constructing foundation piles, characterized by carrying out a refilling process.   The construction method according to any one of claims 1 to 4, wherein the pile driving step is performed by press-fitting the pile using the weight of the pile driving machine. Construction method.

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