JP3245670B2 - Repair method of foundation pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing foundation piles, and more particularly to a method for repairing and rehabilitating foundation piles damaged by an earthquake or the like.

[0002]

2. Description of the Related Art Recently, a large earthquake (the Great Hanshin Earthquake, occurred on January 17, 1995) in the Hanshin area severely damaged many concrete structures. It has been found that the stakes have also received considerable damage.

[0003] Since concrete structures are built on or near the ground, those that cannot be used can be dismantled and removed, but foundation piles, especially those cast in place, have a large diameter and penetrate deep into the ground. Therefore, it is very difficult to dismantle and remove it, and it is hoped that it will be repaired and rebuilt to return to the current state.

[0004] The present invention has been made in view of such a demand.

[0005]

[Means for Solving the Problems] The present invention relates to a method for repairing a foundation pile in which a crack has occurred due to an earthquake or the like, and drills a small-diameter vertical hole from the upper end to the lower end of the foundation pile to be repaired. And then repair the groundwater in the pit by the difference in specific gravity.
Completely replaces liquid material and communicates with cracks and cracks
In the pit to confine groundwater in the ground
With the liquid material filled, the curing of the repair liquid material starts.
In the meantime, the present invention relates to a method for repairing a foundation pile, characterized in that a repair liquid material is injected and filled while stepping up with a double packer means into a crack portion of the foundation pile through a vertical hole.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic explanatory view of a foundation pile 1 to be repaired by the method of the present invention, in which a cast-in-place pile is shown, and a footing 2 is integrally formed at the upper end thereof. A concrete structure 3 is built on top.

[0008] The cast-in-place foundation pile 1 is usually 1000-
It has a diameter of about 1500 mm and a diameter of about 3000 mm for a large diameter one, and the penetration depth is usually about 10 to 50 mm.

[0009] When a large earthquake such as the Great Hanshin Earthquake occurs, the foundation pile 1 is considerably damaged regardless of the fact that it is penetrated underground, and as shown schematically in the figure, In many cases, cracks of various sizes, from fine to relatively large, are mixed.

FIGS. 2 (a) and 2 (b) schematically show the state of a drilling step. As shown in FIG. 2 (a), drilling is performed by applying, for example, a core boring means 4, and footing is performed. A vertical hole 5 having a depth extending from 2 to the vicinity of the lower end of the pile 1 through the upper end of the foundation pile 1 is formed. In this vertical hole 5, FIG.
As shown in FIG. 7, the groundwater 6 will eventually penetrate and stay through the cracks 7 of the foundation pile 1 to a height substantially equal to the groundwater level.

The pit 5 is used as a passage for injecting and filling the repair liquid material. Considering an adverse effect on the strength of the foundation pile, the vertical hole 5 is provided within a range that does not hinder the filling and filling of the repair liquid material.
It is preferable that the diameter is as small as possible.
It is appropriately selected and determined from a range of about 100 mm (diameter).

Although FIG. 2 shows a case where the vertical hole 5 is drilled while the footing 2 is left, the drilling may be performed after the footing is dismantled and removed.

FIGS. 3 (a) and 3 (b) schematically show a state of a step of filling the vertical hole 5 with the repairing liquid material 8, and
As shown in FIG. 3 (a), the filler is injected and filled upward from the lower end of the vertical hole 5 through the injection hose 9.

Since the repairing liquid material 8 has a specific gravity of about 1.10 to 1.20 depending on the kind thereof, by continuing the injection and filling of the liquid material 8 as shown in FIG. ), The groundwater in the pit 5 can be completely replaced with the liquid material 8. Further, after the complete replacement, the groundwater can be completely contained in the crack and the ground communicating therewith due to the specific gravity difference.

After the filling and filling of the liquid material 8 into the vertical hole 5, the filling hose 9 is withdrawn and collected.

As the liquid material 8 for repair, various known liquid materials used for repairing concrete cracks can be used, and may be either organic or inorganic.

As the organic repair liquid material, for example, an epoxy resin liquid can be used after adjusting the pot life to about 1 to 4 hours. The viscosity can be selected from a wide range. However, in order to uniformly and uniformly inject and fill from fine cracks to relatively large cracks, those having a low viscosity region having good permeability, such as 2
000 centipoise or less, preferably 100 to 150
A material having 0 centipoise, more preferably about 500 to 1000 centipoise is suitable.

As an inorganic repair liquid material, for example, cement milk can be used after adjusting the pot life to about 1 to 4 hours. The particle size of the cement particles can be selected from a wide range. However, in order to uniformly and uniformly inject and fill from fine cracks to relatively large cracks, fine particles having good permeability, for example, having an average particle size of 2 ~ 8 μm, preferably 4 ~
A thickness of about 6 μm is appropriate. By the way, average particle size 4 ~
6 μm includes those having a particle size in the range of about 0.5 to 10 μm.

After the repairing liquid material 8 is injected and filled into the pit 5, as shown in FIG.
A hollow rod 12 having 0, 11 is inserted and installed.

The double packers 10 and 11 can be expanded and contracted via remote control means (not shown), inserted into the vertical hole 5 in a contracted state, and then expanded. Due to this expansion, a limited space 13 necessary for injecting and filling the repair liquid material is formed between the double packers 10 and 11.

Next, using the limited space 13, the space 1
The situation of the occurrence of cracks communicating with No. 3 is investigated in advance.

The pre-investigation may be performed by any method capable of grasping the state of occurrence of cracks to some extent. For example, means shown in FIG. 4 can be employed. That is, compressed air is supplied to the source 14.
Is supplied into the limited space 13 through a conduit 15, and the supply amount is measured by a flow meter 17 installed on the conduit 15. This supply is continued until the pressure gauge 16 installed on the conduit 15 reaches a predetermined value exceeding the groundwater pressure. When the pressure reaches the predetermined value, the supply is stopped, and after the stoppage, the time required for the cage pressure to drop to the groundwater pressure. Is measured.

As the amount of cracks generated (total volume) increases, the amount of air supply increases and the rate of decrease in cage pressure increases. I understand to some extent.

After the preliminary investigation, the operation of injecting and filling the repair liquid material 8 is started.

As shown in FIG. 4, the repair liquid material 8 is accommodated in, for example, a closed container 18 so as to be able to be appropriately replenished. When a high-pressure gas (for example, nitrogen gas) is supplied from a high-pressure cylinder 19 through a conduit 20 into the gas-phase portion 18a of the container 18 under a pressure exceeding groundwater pressure, the liquid material 8 in the container 18 is supplied by the high-pressure gas. While being extruded, it is supplied into the limited space 13 through the conduit 21, and is further injected and filled into the crack portion communicating with the space 13.

Since the liquid material 8 has a low viscosity or a fine particle size and is excellent in permeability, the liquid material 8 is uniformly and uniformly filled from a fine crack to a relatively large crack.

By continuing the injection and filling operation under a pressure exceeding the groundwater pressure for a predetermined time based on the data obtained in the preliminary investigation, all the cracks communicating with the limited space 13 are formed. On the other hand, the repairing liquid material 8 can be stably and reliably injected and filled.

After the filling and filling operation at the lowermost stage shown in FIG. 4 is completed, the valve 21a on the conduit 21 is closed to stop the supply of the liquid material 8, and the packers 10, 11 are reduced in size by remote control. After that, the rod 12 is operated to perform one step-up, and at that position, the packers 10 and 11 are expanded again to form a limited space, and then a preliminary survey is performed in the same manner as in the lowermost stage, and the preliminary survey is performed. With reference to the data obtained by the above, the filling operation of the repair liquid material is performed for a predetermined time, and thereafter, the step-up is repeated over the entire length of the vertical hole 5, whereby the foundation pile 1 can be repaired over the entire length.

During the cracking, particularly at the very fine cracks, the filling and filling of the repairing liquid material progresses only gradually, and the filling and filling may not be sufficient only by repeating the above-described step-up operation. There is.

In this case, as shown in FIG. 5, after the repair of the entire length by repeating the step-up is completed, the liquid material is pressed into the vertical hole 5 until the curing of the repairing liquid material starts. By continuing the filling, the shortage of the filling can be eliminated or reduced.

In the present invention, the preliminary investigation is replaced by a step-up operation for filling and filling the repair liquid material.
It may be carried out after the formation of the vertical hole 5 shown in FIG.

In this case, the preliminary investigation is performed by using the hollow rod having a double packer, for example, by the method described above, and data at each step-up position may be obtained.

It is not always necessary to carry out a preliminary investigation. For example, during the initial operation of the filling and filling of the repairing liquid material, the state of the occurrence of cracks can be grasped to some extent from the filling and filling speed of the repairing liquid material. The injection filling amount may be controlled.

[0034]

According to the method of the present invention, the repair liquid material can be uniformly and uniformly filled into the cracks of the foundation pile, from fine to relatively large, so that it cannot be visually confirmed. Repair of piles can be performed easily and with high reliability.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a foundation pile to be repaired according to the present invention.

FIG. 2 is an explanatory view schematically showing a state of a drilling step in the method of the present invention.

FIG. 3 is an explanatory view schematically showing a process of replacing groundwater with a repairing liquid material in a pit.

FIG. 4 is an explanatory view schematically showing a situation of a filling and filling step of a repair liquid material.

FIG. 5 is a schematic explanatory view of a process from the injection and filling of the repairing liquid material to the start of curing of the liquid material.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 foundation pile 2 footing 3 concrete structure 4 air boring means 5 pit 6 groundwater 7 crack 8 repair liquid material 9 injection hose 10 packer 11 packer 12 hollow rod 13 limited space 14 compressed air supply source 15 conduit 16 pressure gauge 17 flow meter 18 closed container 19 high pressure cylinder 20 conduit 21 conduit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayoshi Matsunaga 3-1-11 Tatsudagawa, Heigun-cho, Ikoma-gun, Nara (72) Inventor Jun Kawai 8-8-27 Kamikita, Kamikita, Hirano-ku, Osaka-shi, Osaka Prefecture 48-701 (72) Inventor Masaaki Ohinata 3-3-20 Kikyogaoka Minami, Nabari City, Mie Prefecture (56) References JP-A-63-223228 (JP, A) JP-A-3-28416 (JP, A) 5-18120 (JP, A) JP-A-57-180720 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 5/64 E02D 37/00 E04G 23/02

Claims (3)

(57) [Claims] 1. A method for repairing a foundation pile in which a crack has occurred due to an earthquake or the like, wherein a small-diameter pit is drilled from the upper end to the lower end of the foundation pile to be repaired . Groundwater
Is completely replaced with the repair liquid material by the difference in specific gravity.
Confining groundwater in cracks and ground connected to it
While it filled with repair liquid material into the vertical bore as, 該補
Before the hardening of the repair liquid material starts, the repair liquid material is injected and filled into the crack portion of the foundation pile through the pit under the application of the double packer means and step-up. Repair method for foundation pile. 2. The repair method according to claim 1, wherein the repair liquid material is a low-viscosity epoxy resin-based liquid material. 3. The repair method according to claim 1, wherein the repairing liquid material is fine-grain cement milk.