JP2879201B2 - Restoration method for structural foundation - 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 of filling and repairing a cavity in a foundation of a structure caused by land subsidence with a filler.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 6, a foundation 2 of a large building (structure) is provided with a foundation 2 on a plurality of piles 1 driven into a ground A, and a foundation beam 3 is provided between each foundation 2. And connect
The foundation 2 supports the pillars 4 of the building B, the ground crushed stones 5 are arranged on the ground surface C, and a flat slab 6 as a floor of the building B is cast on the ground crushed stones 5. Beneath the flat slab 6 (including the crushed stone 5) as a floor, pipes 7 such as sewage pipes, water pipes, gas pipes, etc., and wiring cables 7 are arranged. , Usually embedded in the ground A.

It is well known that liquefaction proceeds in response to earthquake motion when the ground is sandy ground, and even in the recent Great Hanshin Earthquake, the liquefaction often causes ground surface subsidence. , Has caused a great deal of damage. Also, in the viscous ground, the phenomenon that the ground surface subsidence occurs due to the compaction of the ground is often observed. However, when the ground surface subsidence occurs at the foundation portion including the pile 1, the position of the building B is maintained by the pile 1, and as shown in FIG. A cavity D is generated between the flat slab 6 and the lower surface of the floor. And, if this cavity D is left as it is, the horizontal force generated in the building by the earthquake becomes difficult to be transmitted to the ground, and it becomes insufficient as a preparation for the earthquake. Therefore, the cavity D is filled with a filler such as sand. It is necessary to return the foundation to its original condition.

On the other hand, since the pipes 7 are buried in the base portion as described above, when the ground surface sinks as described above, the pipes 7 are exposed in the cavity D. In this case, as shown in FIG. 7, a part of the foundation crushed stone 5 and the earth and sand 8 (remaining material) often remain on the upper side of the piping 7, and the piping 7 is loaded by the load of the remaining material. It may be deformed or damaged, in which case it is necessary to repair or replace the piping before backfilling.

[0005]

However, it is assumed that the ground that causes land subsidence will re-settle due to the subsequent earthquake or consolidation. Therefore, as described above, the cavity D is simply filled with the filler and filled. If it is returned, there is a risk that the piping 7 will be damaged again by the subsequent re-sinking. Therefore, at the time of the first backfilling, it is desirable to reinforce the pipes 7 by some method. However, it is impossible to use the ground as a support base, and the work is performed in a narrow cavity D. The equipment is also limited, and there has been no appropriate reinforcement measures in the past.

The present invention has been made in view of the above background, and an object of the present invention is to make it possible to easily and surely reinforce pipes even in a narrow cavity, thereby effectively coping with the settlement of the ground surface. It is an object of the present invention to provide a method of repairing a structural base part which can be performed.

[0007]

In order to achieve the above object, the present invention sprays a foaming undiluted solution around pipes exposed in a cavity caused by subsidence of the ground surface, and applies the foaming solution to a ceiling in the cavity. The method is characterized by comprising a first step of bonding and forming a foam surrounding pipes and a second step of filling a filler around the foam around the foam.

According to the present invention, prior to the second step, a foaming liquid is locally sprayed into the cavity to form a partition wall of a foam which partitions the cavity, and the second step is surrounded by the partition wall. Alternatively, the processing may be performed in units of the selected area.

[0009]

In the method of repairing the foundation of a structure constructed as described above, not only is the foam adhered to the ceiling in the cavity but the pipes are reinforced, and the foam is used to fill the upper side of the pipes. Pipes are not deformed even if the wraparound of materials is regulated and the ground surface re-settles.

In the case where the partition wall is formed of a foam and the second step, that is, the filling of the filler is performed in units of an area surrounded by the partition wall, a single work area may be set in accordance with the work capacity. Can be set.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 3 show an embodiment of a method of repairing a structural foundation according to the present invention. In these figures, the same parts as those shown in FIGS. 6 and 7 are denoted by the same reference numerals. When the settlement of the ground surface C occurs at the foundation portion including the pile 1 as described above, a new ground surface C ′ caused by the settlement and the lower surface of the flat slab 6 as the floor of the building B as shown in FIGS. And a pipe D is exposed in the hollow D.
In this case, a part of the foundation crushed stone 5 and the earth and sand 8 remain on the upper side of the pipes 7 as remnants. In the present embodiment, first, including the remnants, the entirety of the pipes 7 and around the same, A foaming liquid is sprayed from an injection nozzle (not shown) to form a foam 10 adhered to the lower surface of the flat slab 6, and the piping 10 is wrapped by the foam 10 (FIG. 1,
2) After that, the filling material 11 is filled into the cavity D around the foam body 10 by using an appropriate filling machine (not shown) (FIG. 3).

As the foam 10, it is desirable to use a foam which has good adhesion to the flat slab (concrete) 6, is lightweight, has high mechanical strength, and is excellent in spraying workability. As such a foam material,
For example, there is a polyurethane foam. At the time of spraying the foaming undiluted solution, if the cavity D is large enough to enter, an operator may enter the cavity D and manually operate the injection nozzle. A spraying device having an endoscope and an endoscope may be inserted into the cavity D through a hole provided in the flat slab 6, and may be performed unattended. In the case of spraying unattended, not only dangerous work and unsanitary work can be avoided, but also construction in a narrow cavity where no people can enter is possible. On the other hand, the filler 11
It is desirable to use a material having good fluidity, high compressive strength and low cost. As such a filling material, for example, there is an ace sand made by Shinko. This ace sand is made by mixing sand, water, a foaming agent, cement, etc. with sand as a main component and further mixing air to form an air mortar.For example, using an squeeze type concrete pump truck, this ace sand is used. It is pumped into the cavity D. In this case, the flat slab 6
A hole for venting air is provided in advance.

As described above, the pipes 7 are wrapped in advance with the foam 10 and then filled with the filler 11 so that the adhesive strength of the foam 10 to the flat slab 6 causes
The load of the remaining material (part of the foundation crushed stone 5 and the earth and sand 8) is offset, and the surroundings of the filler 11 on the upper part of the pipes are regulated, after which an earthquake again occurs and the ground surface re-sinks Even so, the piping 7 is not deformed, and the need for repair and replacement is eliminated. In addition, since only the foaming undiluted solution is sprayed, the work can be performed if there is an air space in which the injection nozzle can be operated, and it can be effectively performed even in the narrow cavity D.

Here, the filling of the filling material 11 into the cavity D is generally performed continuously in a region surrounded by the foundation beam 3 as a unit, but when the region is wide,
Filling within a predetermined time becomes difficult due to the construction ability, and overwork may be unavoidable. in this case,
As shown in FIG. 4, the foaming undiluted solution is locally sprayed onto an appropriate place in the cavity D generated by the subsidence of the ground surface to form a partition wall 12 made of a foam.
Are divided into appropriate sizes, and the filler 11
To be filled. Thereby, it becomes possible to fill the filler 11 in accordance with the construction capacity, and it is possible to prevent the occurrence of the above-mentioned overwork.

In addition, as shown in FIG. 5, the ground surface C may be severely settled, and the new ground surface C 'may be lower than the foundation beam 3 or the foundation 2 to form a gap 13 between them. In this case, at the time of filling the filler, the filler escapes through the gap 13, and a substantially one-time application area is expanded.
Also in this case, by filling the gap 13 with the foaming undiluted solution and forming the partition wall 14 in cooperation with the foundation beam 3 or the foundation 2, the filler can be filled within a limited range. Overwork can be prevented from occurring.

[0017]

As described above in detail, according to the method of repairing the foundation of a structure according to the present invention, pipes can be reinforced by a simple measure of spraying a foaming liquid, so that the ground surface can be rebuilt. Damage to the piping due to settlement can be prevented beforehand, and the reliability of repairing the foundation can be significantly improved. Also,
If a partition wall is formed from foam and filling is carried out in units of the area surrounded by the partition wall, a single work range can be set according to the work capacity, and Can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an initial state of implementation of a repair method according to the present invention.

FIG. 2 is an enlarged sectional view showing a part of FIG. 1 in an enlarged manner.

FIG. 3 is a cross-sectional view showing a final state of the execution of the restoration method.

FIG. 4 is a cross-sectional view showing another embodiment of the repair method according to the present invention.

FIG. 5 is a sectional view showing still another embodiment of the repair method according to the present invention.

FIG. 6 is a sectional view showing a general structure of a basic portion of a structure.

FIG. 7 is a cross-sectional view showing a failure occurrence state in a foundation portion of the structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pile 2 Foundation 3 Foundation beam 4 Structural column 5 Foundation crushed stone 8 Earth and sand 10 Foam 11 Filler 12 Partition wall

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 37/00

Claims (2)

(57) [Claims] 1. A method of filling and repairing a cavity in a foundation portion of a structure caused by subsidence with a filler, and spraying a foaming undiluted solution around piping exposed in the cavity. A method for restoring a basic portion of a structure, comprising: a first step of bonding and forming a foam wrapping the pipes on a ceiling in the cavity; and a second step of filling a cavity around the foam with a filler. 2. Prior to the second step, a foaming liquid is locally sprayed into the cavity to form a partition wall of a foam which partitions the cavity, and the second step is a region surrounded by the partition wall. The method for repairing a foundation portion of a structure according to claim 1, wherein the method is executed in units of a unit.