JP5742058B2 - Method for increasing horizontal resistance of precast concrete pile foundation - Google Patents

Description

  The present invention relates to a method for increasing the horizontal resistance force of a ready-made concrete pile foundation in which the horizontal resistance of the pile does not decrease even after receiving an excessive horizontal displacement when a large earthquake occurs in a foundation using a ready-made concrete pile.

  In recent years, as a method to increase the horizontal resistance of the upper end of a concrete pile foundation using a ready-made concrete pile, the upper end of the ready-made concrete pile built in the ground, that is, the bottom of the building supported on the upper end of the ready-made concrete pile foundation A method has been developed in which a wall-like improved ground is created between ground ready-made concrete piles to increase the horizontal resistance (for example, Patent Document 1).

  In addition, for the same purpose, a method of integrally constructing an enlarged diameter part by on-site construction on the pile head (for example, Patent Document 2) and a large-diameter horizontal resistor placed on the pile head integrally with the building footing are constructed. The horizontal resistor and the upper end of the ready-made concrete pile are configured to move relative to each other in the horizontal direction to reduce the horizontal force on the pile, and the horizontal resistor on the upper end of the pile receives the horizontal resistance force. (For example, Patent Document 3) has been developed.

JP 2010-121368 A JP 2006-37491 A JP 2007-9457 A

  As shown in the above-mentioned Patent Document 1, a method of creating a wall-like improved ground by using soil cement by continuous ground improvement between the heads of ready-made concrete piles built in the ground causes a large earthquake. If the wall-shaped improved ground due to soil cement breaks due to excessive horizontal force acting at times, etc., the force against horizontal force will drop, and then the originally planned horizontal resistance will be lost and it will have to be rebuilt. There is a problem that it must be done.

  On the other hand, as described in Patent Document 2, both the method of integrally building the enlarged diameter portion by the construction on site and the method of creating a horizontal resistor different from this on the pile head are continuous with the pile head. A construction with a cast-in-place reinforced concrete structure is formed by on-site construction, and processes such as installation of formwork in the ground, reinforcement, placement of concrete, and removal of formwork are required. While it becomes high, since it is construction by cast-in-place concrete, quality becomes unstable compared with the blur cast part, and there is a possibility that required strength cannot be obtained.

  In view of the above-described conventional problems, the present invention provides a horizontal resistance increasing body that is not easily damaged even by an excessive horizontal force and that provides a sufficient increase in horizontal resistance force, and is the most effective part for a ready-made concrete pile. In addition, it was made for the purpose of providing a method for increasing the horizontal resistance of a ready-made concrete pile foundation that can be easily installed.

    The feature of the invention described in claim 1 is that flange-shaped upper and lower flanges are vertically spaced at a desired height position of the upper end portion of the ready-made concrete pile inserted into the ready-made concrete pile insertion hole formed in advance by excavation. A partition plate is provided, and the ready-made concrete pile is built in the ready-made concrete pile insertion hole, and a cylindrical casing having an inner diameter with which the upper and lower partition plates are fitted in the enlarged-diameter hole portion, the both partition plates Insert the fluidized solidifying material such as cement milk into the horizontal resistance increasing body forming part surrounded by the casing, the upper and lower partition plates and the surface of the prefabricated concrete pile, by inserting it to a height that spans between The horizontal resistance increasing body integrated with the upper and lower partition plates is integrally formed at a desired height position on the outer periphery of the upper end of the ready-made concrete pile, and after the fluidized solidifying material is injected, the flow Solidifying material is in a horizontal resistance force method of increasing pre-cast concrete pile foundation made be characterized by waiting to solidify enough to exhibit shape retention withdrawing said casing.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, when the ready-made concrete pile is installed in the ready-made concrete pile insertion hole, An enlarged hole portion having a depth reached by the partition plate is formed, and the cylindrical casing is inserted into the enlarged hole portion up to a height across the partition plates.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, a vertical reinforcing bar and a vertical direction are arranged between the upper and lower partition plates at a desired interval in the circumferential direction of the partition plate. It is to provide lateral reinforcing bars arranged at desired intervals.

  According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the casing is provided with a fluidized solid material injection pipe disposed vertically along the outer surface thereof. The lower end of the pipe is opened into the lower end of the horizontal resistance increasing body forming portion, and the flowable solidification material is injected through the flowable solidification material injection pipe.

  In the method for increasing the horizontal resistance force of a ready-made concrete pile foundation according to the present invention, as described in claim 1, a desired height of an upper end portion of the ready-made concrete pile to be inserted into a ready-made concrete pile insertion hole that has been excavated and formed in advance. At this position, there are provided flange-shaped upper and lower partition plates spaced vertically, and the ready-made concrete piles are built in the ready-made concrete pile insertion holes, and the upper and lower partition plates are installed in the enlarged-diameter holes. A cylindrical casing having a fitting inner diameter is inserted to a height that spans between the two partition plates, and the lower end thereof is formed in the horizontal resistance increasing body forming portion surrounded by the casing, the upper and lower partition plates, and the surface of the ready-made concrete pile. By injecting a fluidized solidifying material such as cement milk from the side, the horizontal resistance increasing body is integrated and installed for each ready-made concrete pile. Because it is reinforced by the cut plate, when an excessive horizontal force is applied to the upper end of the ready-made concrete pile, it will be difficult to break with the ready-made concrete pile, and it will be necessary to repair the ready-made concrete pile foundation. It is possible to construct a ready-made concrete pile foundation with very little situation, high durability and high horizontal resistance.

  Further, a horizontal resistance increasing body integrated with the upper and lower partition plates is integrally formed at a desired height position on the outer periphery of the upper end of the ready-made concrete pile, and the casing is pulled out after the fluidized solidifying material is injected. As a result, the casing can be reused, and the construction cost is reduced. Note that the casing is pulled out after it is solidified to such an extent that the injected fluidized solidifying material exhibits shape retention so that the drawing operation becomes easy.

  In this invention, when the said ready-made concrete pile is built in the said ready-made concrete pile insertion hole as described in Claim 2, the lower partition plate in the said both partition plates reaches | attains. A diameter expansion hole portion having a depth is formed, and the cylindrical casing is inserted into the diameter expansion hole portion up to a height across the partition plates, thereby preparing a ready-made concrete pile and a ready-made concrete pile insertion hole. And the amount of filler such as soil cement to fill the gap can be reduced.

  In the present invention, as described in claim 3, the horizontal resistance increasing body is provided with vertical reinforcing bars between the upper and lower partition plates at a desired interval in the circumferential direction of the partition plates. The structure is reinforced by the upper and lower partition plates and the reinforcing bars between them, and even when soil cement is used as the material, the required strength can be obtained and the construction is facilitated.

  In the present invention, as described in claim 4, the casing includes a fluidized solid material injection pipe arranged vertically along an outer surface thereof, and a lower end of the pipe is the horizontal resistance increasing body forming portion. Since the fluidized solidified material is injected through the fluidized solidified material injection pipe, the fluidized solidified material is accurately filled, and a horizontal resistance increasing body with stable quality can be formed. .

It is a longitudinal cross-sectional view which shows an example of the ready-made concrete pile foundation constructed | assembled by the horizontal resistance increasing method by this invention. It is explanatory drawing which shows the construction process of the horizontal resistance increasing method which concerns on this invention. It is a partial expanded sectional view which shows the casing mounting state in the method same as the above. The example of fixation with the ready-made concrete pile and partition plate in the method same as the above is shown, and is a half-longitudinal front view in which the right half is vertically cut.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  FIG. 1 shows an example of a ready-made concrete pile foundation with increased horizontal resistance constructed by the method of the present invention. In the figure, reference numeral 1 is a ready-made concrete pile, 2 is a ready-made concrete pile insertion hole, and 3 is an enlarged bulb of soil cement formed at the lower end of the ready-made concrete pile insertion hole 2.

  A horizontal resistance increasing body A is integrally formed in the ground at a desired depth from the upper end of the ready-made concrete pile 1. This horizontal resistance increasing body A has flange-like upper and lower partition plates 10, 10 fixed on the upper and lower sides of the ready-made concrete pile 1 at a desired interval. For example, as shown in FIG. 4, the upper and lower partition plates 10, 10 are fixed to the ready-made concrete pile 1 by anchor bolts 12 with tongue-like fixing pieces 11 provided integrally with each partition plate 10. It is made by.

  Between the two partition plates 10, 10, a plurality of reinforcing bars 13, 13. each consisting of a longitudinal reinforcing bar arranged at a desired interval in the circumferential direction of the divider plate and a transverse reinforcing bar arranged at a desired interval in the longitudinal direction. ... Are installed, and the partition plates 10 and 10 are connected by the above-described vertical reinforcing bars. The reinforcing bars 13 reinforce the horizontal resistance increasing body A.

  The expanded bulb 3 is inserted at the lower end of the ready-made concrete pile 1 into a filler made of soil cement in which cement milk is injected and mixed in the mud of the enlarged bulb diameter expanding portion 3a obtained by enlarging the lower end of the ready-made concrete pile insertion hole 2. It has been solidified.

The gap between the inner surface of the ready-made concrete pile insertion hole 2 above the enlarged bulb 3 and the ready-made concrete pile 1 and the outer periphery of the horizontal resistance increasing body A are filled with soil cement having a quality different from that of the enlarged bulb 3. 14 buried.
The construction method of the ready-made concrete pile foundation comprised in this way is demonstrated.

  As shown in FIG. 2A, a diameter expansion hole 20 for forming the horizontal resistance increasing body A is excavated from the ground surface by using an excavation head 21 for forming the diameter expansion hole. The diameter-expanded hole 20 is formed at a depth equal to or deeper than the installation depth of the horizontal resistance increasing body A, and the horizontal height of the ground is set at a position where the horizontal resistance increasing body A is close to the ground surface. It is formed at a depth where the supporting force is large.

  Next, as shown in FIG. 2 (b), the ready-made concrete pile insertion hole 2 is formed by connecting the excavation head 23 for forming the ready-made concrete pile insertion hole to the tip of the excavation work shaft 22. As the excavation head 23, one having an expansion excavation blade 24 is used, and as shown in FIG. 2 (c), an enlarged bulb diameter expansion portion 3a is formed at the lower end portion of the ready-made concrete pile insertion hole 2. In the formation of the ready-made concrete pile insertion hole 2, the ground is excavated with a drill bit while injecting excavated water, and in the ready-made concrete pile insertion hole 2 after excavation, mud soil in which the excavated earth and sand are mixed The work is carried out while maintaining the state of being filled.

  After forming the ready-made concrete pile insertion hole 2 in this way, cement milk is injected into the enlarged bulb diameter expanding portion 3a from the drill water injection nozzle provided in the excavation head 23, and stirred by the expanded excavation blade 25. A filler 26 made of soil cement is filled into the enlarged bulb diameter expanding portion 3a.

  Next, as shown in FIG. 2 (d), the excavation head 23 is stirred while being rotated while pouring cement milk into the mud in the hole 2 with the expanded excavation blade 25 folded to the shaft side. Then, a filler 27 made of soil cement having a desired cement concentration is extracted in a state of being filled in the ready-made concrete pile insertion hole 2.

  After forming the ready-made concrete pile insertion hole 2, the enlarged bulb enlarged diameter portion 3a at the lower end and the enlarged diameter hole portion 20 at the upper end in this way, the ready-made concrete pile 1 is inserted. In the ready-made concrete pile 1, the upper and lower partition plates 10, 10 described above are fixed in advance at a predetermined height, and a reinforcing bar 13 is fixed between the partition plates 10, 10. Reinforcing bar 13 and partition plates 10 and 10 are preliminarily formed into a cylindrical shape and fitted to ready-made concrete pile 1 and fixed at a desired height.

  A guide body 28 having the same diameter as or slightly smaller than the upper and lower partition plates 10 and 10 is fixed in a flange-like arrangement at a position spaced apart from the upper partition plate 10.

  The ready-made concrete pile 1 to which the guide body 28 and the upper and lower partition plates 10 and 10 and the reinforcing bar 13 are mounted is inserted into the ready-made concrete pile insertion hole 2 as shown in FIG. At this time, the lower end of the ready-made concrete pile 1 is inserted into the filling 26 for the rooting bulb 3, and a filling 27 made of soil cement is provided in the gap between the inner surfaces of the ready-made concrete pile 1 and the ready-made concrete pile insertion hole 2. Is filled, and the filler above the lower partition plate 10 in the enlarged diameter hole portion 20 at the upper end of the ready-made concrete pile insertion hole 2 is extracted, and the ready-made concrete pile 1 and the enlarged diameter hole portion 20 The gap with the inner surface is a cavity.

  Next, as shown in FIGS. 2 (f) and 3, a cylindrical casing 30 that forms the outer periphery of the horizontal resistance increasing body A is mounted. The casing 30 has a cylindrical shape with an inner diameter in which the upper and lower partition plates are fitted, and a vertically flowing fluidized solid material injection pipe 31 is provided along the outer peripheral surface thereof.

  The lower end of the fluidized solid material injection pipe 31 passes through the lower end portion of the casing 30 and is open to communicate with the inside thereof. The casing inner surface opening of the fluidized solidifying material injection pipe 31 is formed in advance so as to be located above the lower partition plate 10 when the casing 30 is mounted on the ready-made concrete pile 1.

  In addition, the casing 30 is mounted such that the guide body 28 is used as a guide on the inside, is inserted to a height that spans between the partition plates 10 and 10, and the upper end is positioned outside the guide body 28.

  After mounting the casing 30, as shown in FIG. 2 (g), in the horizontal resistance increasing body forming portion surrounded by the casing 30, the upper and lower partition plates 10 and 10, and the surface of the ready-made concrete pile 1, fluidity solidification is performed. Cement milk 32, which is a fluidized solidifying material, is injected through the material injection pipe 31. After the cement milk is poured, the casing 30 is pulled out after it is solidified to such an extent that the shape retainability is exhibited.

Thereby, the horizontal resistance increasing body A larger than the diameter of the ready-made concrete pile 1 reinforced by the reinforcing bar between the partition plates 10 and 10 is formed.
In addition, as a fluid solidification material, mortar other than cement milk may be sufficient.

  Moreover, although the case where the inside of a casing is hollow at the time of cement milk injection | pouring of the horizontal resistance increasing body A is shown in the above-mentioned example, in the state which inserted the ready-made concrete pile 1 in the ready-made concrete pile insertion hole 2 The state in which the expanded hole portion 20 is filled with the filling 27 and the casing 30 is mounted in this state so that the casing 30 between the upper and lower partition plates 10 and 10 is also filled with the filling 27. In this state, the cement milk 32 may be injected from the pipe 31 to push up the filler 27 and replace it with the cement milk 32. Also, the cement milk 32 is mixed in the filler 27. High quality soil cement may be used.

  As shown in FIG. 1, the gap between the enlarged diameter hole portion 20 after the casing 30 is extracted and the horizontal resistance increasing body A is filled with a filler 33 such as cement mortar or soil cement, and the horizontal resistance increasing body A The horizontal force applied to the ground is supported by the ground 32.

  The horizontal resistance increasing body A configured in this manner is installed integrally with the ready-made concrete pile 1 at a position where the supporting force of the ground close to the ground surface is large, and for each ready-made concrete pile, When an excessive horizontal force is applied to the upper end of the pile 1, it is difficult to break by moving horizontally with the ready-made concrete pile, and there is very little need for repair of the ready-made concrete pile foundation, and the durability is high. A ready-made concrete pile foundation with high horizontal resistance can be constructed.

  In addition, in the above-mentioned example, although the case where the reinforcing bar 13 is installed between the upper and lower partition plates 10 and 10 is shown, the number of the reinforcing bars is the material constituting the horizontal resistance increasing body A, for example, cement milk, mortar, Depending on the quality of the soil cement or the like, the number of the required strength is selected. If the strength of the constituent material of the horizontal resistance increasing body A is high, the reinforcing bars 13 need not be used.

  In addition, in this example, although the example at the time of forming the enlarged diameter hole 20 in the upper end part of the ready-made concrete pile insertion hole 2 is shown previously, the whole area of the ready-made concrete pile insertion hole is shown as the enlarged diameter hole 20. You may carry out to the ready-made concrete pile insertion hole which does not have after diameter expansion holes, such as forming in the same diameter.

A Horizontal resistance increasing body 1 Ready-made concrete pile 2 Ready-made concrete pile insertion hole 3 Expanded bulb 3a Expanded bulb diameter expanding portion 10 Partition plate 11 Fixing piece 12 Anchor bolt 13 Reinforcement 14 Filling material 20 Expanded hole portion 21 Drilling head 22 Excavation work Shaft 23 Drilling head 24 Expanded digging blade 25 Expanded digging blade 26 Filled material 27 Filled material 28 Guide body 30 Casing 31 Fluidity solidifying material injection pipe 32 Cement milk 33 Filled material

Claims (4)

At the desired height position of the upper end portion of the ready-made concrete pile inserted into the ready-made concrete pile insertion hole formed in advance, a flange-shaped upper and lower partition plates spaced apart vertically are provided,
The ready-made concrete pile is built into the ready-made concrete pile insertion hole, and a cylindrical casing having an inner diameter with which the upper and lower partition plates fit into the enlarged-diameter hole is inserted to a height across the partition plates. ,
By injecting a fluidized solidifying material such as cement milk into the horizontal resistance increasing body forming portion surrounded by the casing, the upper and lower partition plates and the surface of the ready-made concrete pile, the outer periphery of the upper end of the ready-made concrete pile is injected. A horizontal resistance increasing body integrated with the upper and lower partition plates is integrally formed at a desired height position of
A method for increasing the horizontal resistance force of a ready-made concrete pile foundation, wherein after the fluidized solidifying material is injected, the casing is pulled out after waiting for the fluidized solidified material to solidify to such an extent that shape retainability is exhibited.     In the ready-made concrete pile insertion hole, when the ready-made concrete pile is built, a diameter-expanded hole portion having a depth reached by the lower partition plate in the both partition plates is formed, The method for increasing the horizontal resistance force of a ready-made concrete pile foundation according to claim 1, wherein the cylindrical casing is inserted into the diameter-expanded hole portion up to a height across the partition plates.   The vertical reinforcing bar arranged at a desired interval in the circumferential direction of the divider plate and a horizontal reinforcing bar arranged at a desired interval in the vertical direction are provided between the upper and lower divider plates. Of increasing horizontal resistance of ready-made concrete pile foundations.   The casing is provided with a flowable solidifying material injection pipe disposed vertically along the outer surface thereof, the lower end of the pipe being opened into the lower end of the horizontal resistance increasing body forming portion, and the flowable solidified material injection The method for increasing the horizontal resistance of a ready-made concrete pile foundation according to any one of claims 1 to 3, wherein a fluidized solidifying material is injected through a pipe.

Images