JPS609640B2 - Construction method for shielding walls in large underground cavities - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is used in the technical field of constructing the foundations of buildings by densely filling large underground cavities existing under the ground on which a building is to be constructed. The present invention relates to a method for constructing a shielding wall in an underground cavity for use in the construction of a shielding wall, and more particularly to a method for constructing a shielding wall using core materials and tubes for guides as ground work.

(Prior art and its problems, etc.) Underground cavities that impair the bearing capacity of the ground, such as those shown in Figs. When there is an underground sewage system, a coal mine, etc., fillers such as aggregate, mortar, and concrete are usually introduced and injected from the ground to densely fill the underground cavity c.

However, if the underground cavity c is large-scale or continuous for a long time, the injected filling material may flow out,
There is a problem that the filling effect tends to be insufficient due to diffusion, etc., it is difficult to calculate the amount of filler to be used, and in some cases, filler has to be used without limit.
Conventionally, it has been possible to form transverse shielding walls from the ground, such as rows of steel pipe columns or PC columns, at key points in underground cavities, and then fill the confined underground cavities by injecting and filling them. It was done. However, in the case of this method, the part of the columns above the underground cavity that forms the shielding wall is completely wasted, and in particular, the proportion of the useless part is larger than the effective shielding wall part of the underground cavity. It was also very expensive and uneconomical. Next, although the shielding wall construction method described in Japanese Patent Publication No. 54-33052 is applicable to small-diameter cavities where only one tube can expand, it is difficult to shut off when one tube expands. Effective construction work cannot be expected at all for cavities so large that they cannot be constructed.

In other words, if you spread sand to form a seat for the tubes to stably land on, but if two or more tubes are placed next to each other in a series, the tubes will roll randomly toward the side with less resistance and separate. Normally, it would be impossible to form a series of shielding walls. (Objective of the invention, technical problem to be solved) Therefore, the object of the present invention is to easily create a shielding wall for blocking large underground cavities that are so large that they cannot be blocked by the expansion of a single tube. To provide a construction process for a large underground cavity shielding wall that is improved so that it can be formed reliably and quickly at low cost.

(Structure of the Invention, Means for Solving the Problems) In order to achieve the above object, the large underground cavity shielding wall construction method of the present invention is aimed at reaching a confirmed underground cavity from the ground. The process of drilling the required number of holes in the direction across the underground cavity at a pitch approximately equal to the expansion diameter of the tube, the process of fixing the core through the center of each hole, and the process of fixing the flat donut-shaped disc-shaped tube. The tubes are filled with mortar or the like on the ground and expanded, and the tubes are passed through the core material and lowered a required number of times into the hole, and stacked up to the full depth of the underground cavity.

(Effect) As mentioned above, a long core material as a guide is passed through each excavation hole and fixed, and a tube filled with mortar etc. and expanded is passed through this core material and descended into the underground cavity along the core material. Therefore, the position of the tube is reliably defined and fixed by the core material.

Therefore, even if the expanded tubes rub against each other, they will never slip and escape, and the solid shielding wall that crosses the underground cavity in close contact with each other is reinforced with reinforcing bars. It is reliably formed into a single wall with a similar structure.

In other words, no matter how large the underground cavity is, construction can be carried out regardless of its size, making it possible to fill the underground cavity. Of course, by increasing the expanded outer diameter of the tube as much as possible, the number of drilling holes can be reduced.
Moreover, the hole diameter can be made as small as possible to allow for quick and economical construction.

(Example) Next, the illustrated embodiment will be explained.

Figure 1 shows the planar shape of the building site 1, the planar arrangement and form of a harmful underground cavity c existing under the ground, and the shielding walls 21, 22, 23, 24.

FIG. 2 shows a state in which the filling material 5 is filled in the underground cavity c under the building 3 and the ground 4, the constructed shielding walls 2, 2, and the underground cavity c limited thereby. Figure 3A
, B, and C show main process diagrams of the construction method of the shielding wall 2.

That is, do not use an earth auger or the like to vertically excavate a hole 10 from the ground toward the underground cavity c confirmed by boring (Fig. 3A).

Hole 1, the expanded outer diameter of the tube (usually J120), which will be described later.
The required number of excavations are carried out in a line across the underground cavity c at a pitch that is approximately equal to or slightly smaller (about 0 to ◇1500) (Figure 1). Is the diameter of hole 10 normal?
It is 650 to ◇70 bright degrees. Hole 10 thus drilled
1 is directly in the center of each hole 10 4
The core material 11 made of elongated iron having a thickness of 0 to 05 is passed through to reach the underground cavity c, and its lower end is fixed by piercing the bottom surface of the underground cavity c to a certain extent (FIG. 3A).

This core material 11 is used as a guide to guide the descent of the tube and to fix the position of the tube to prevent it from shifting, so as long as it has the necessary strength and straightness, it can be made of any material or have any cross-sectional shape. No question. Next, the flat disc-shaped tube 18 is filled with mortar etc. on the ground in advance, and a required number of tubes are lowered into the underground cavity c along the core material 11 and stacked in order to construct a shielding wall (Fig. 3B ,C). As shown in FIGS. 4A and 4B, the tube 18 has a core material 1 in the center.
The bag is formed of rubber or the like as a flat donut-shaped disc-shaped bag having a through hole 18a large enough to pass through. The outer diameter of the tube 18 is 1200 to 140 degrees. The tube 18 is filled with mortar or the like on the ground and expanded, and the core material 11 is passed through the through hole 18a in the center as shown in FIG. 5A, or the through hole 18a of the tube 18 is pre-filled. Pass it through the core material 11, fill it with mortar, etc., suspend the part near the through hole 18a with the ropes 20, 20 of the textbook, and lower it through the hole 10 along the core material 11 until it reaches the underground cavity c. .

As a result, the tube 18 suspended by the rope 20 deforms into the shape of a vertically long water drop due to its own weight, as shown in FIG.
It is about 570◇, which is smaller than 50~700), and it descends easily through the hole 10.

The tube 18 that reached the bottom of the underground cavity c or was lowered first...The tube 18 placed on top is shown in Figure 5B.
As shown, it lies in its original flat disk-like shape. Similarly, the corresponding number of tubes 1 per hole 10
8 one after another, and underground cavity c at the location of the hole concerned.
Stack them to the full height. Then, the tubes 18 are stacked neatly around the core material 11, and the adjacent tubes are pressed against each other and are intimately attached to each other, forming a series of shielding walls that traverse the underground cavity and completely shield it. (Figure 3C).

That is, the depth of the underground cavity c, which varies depending on the position of the hole 10, can be easily and reliably dealt with by adjusting the number of descents of the tube 18.

[Brief explanation of the drawings] Figure 1 is a plan view showing the relationship between the building site and the underground cavity, Figure 2 is a vertical sectional view showing the relationship between the building and the underground cavity, and Figure 3A ~C are main process diagrams of the shielding wall construction method of this invention, Figures 4A and B are perspective views showing the state of the tube before use and after expansion, and Figures 5A and B are the tubes in the middle of descent. It is an explanatory view showing a state after descent. Figure 1 Figure 2 Figure 3 A Figure 3 B Figure 3 C Figure 4 A Figure 4 B Figure 5 A Figure 5 B

Claims (1)

[Claims] 1. A hole 10 that reaches the confirmed underground cavity c from the ground is made in a direction that crosses the underground cavity c with a hit that is approximately equal to the expansion diameter of the tube described below. A step of excavating the required number of holes, a step of passing the core material 11 through each hole 10 and fixing it, and filling the flat donut-shaped disk-shaped tube 18 with mortar or the like on the ground to expand it, and then attaching the tube 18 to the core material 11. A process for constructing a shielding wall for a large underground cavity, characterized by comprising the step of lowering a required number of walls through a hole 10 and stacking them up to the full depth of the underground cavity c. 2. The tube 18 described in claim 1 is:
A construction method for constructing a shielding wall for a large underground cavity in which the center is suspended by a loaf 20 and lowered into a hole 10.