JP2749625B2 - Shaft bottom forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for constructing a bottom for stopping water in a starting shaft and a reaching shaft of a propulsion method.

[Conventional technology]

Conventionally, water stoppage work performed after excavation of a shaft is performed by supplying water stoppage cement to the bottom of the shaft to form a bottom. For example, a construction method proposed in Japanese Patent Application Laid-Open No. 61-191798 filed earlier by the applicant is mentioned as an example.

FIG. 4 shows a conventional construction method, in which a shaft 2 is formed in the casing 2 by press-fitting the casing 2 and simultaneously excavating the inside thereof, and thereafter, removing the residual soil adhering to the side wall of the casing 2. Leveling of the pit bottom is performed from the ground (Fig. (A)). Operations such as removal of the residual soil and leveling of the pit bottom are performed manually using a shovel S with a long handle, a water jet, or the like. After this operation, concrete is fed to form a bottom at the bottom of the shaft 1, and the inside of the shaft 1 is stopped.

[Problems to be solved by the invention]

After excavating the shaft 1, the groundwater 3 infiltrates the shaft 1, so that the bottom level is submerged. Therefore, when the fresh concrete C is poured using the torumi tube T or the like while submerged (FIG. 4 (b)), water is mixed into the fresh concrete C. For this reason, the ready-mixed concrete C is easily deteriorated, and a problem arises in terms of the water stopping power. In addition, earth and sand
In the case where 3a is contained in the groundwater 3, the quality of the finished bottom is deteriorated by mixing in the ready-mixed concrete C.

Furthermore, the latence in which fine substances float and settle on the surface of the ready-mixed concrete C due to breathing (floating phenomenon).
The occurrence of 3b is also large. For this reason, there has been a problem in that good construction of the bottom is obstructed, and construction such as removal of the latencies 3b and countermeasures against flooding is required.

Therefore, the present invention, in the waterproof cement construction method,
It is an object of the present invention to obtain a good bottom construction by placing a waterproofing cement without mixing groundwater.

[Means for solving the problem]

The present invention causes a concrete bag in the form of a bag in which a concrete supply pipe is connected to an air release pipe to land on the shaft bottom of a shaft,
Fresh concrete is supplied from a concrete supply pipe to a concrete bag in a sealed state against water, and the concrete bag is brought into close contact with the inner wall of the shaft by expansion of the concrete bag by filling with concrete, and the filled concrete is solidified. This is a bottom shaft forming method for a shaft, wherein a bottom plate for stopping water is formed at the bottom.

〔Example〕

Hereinafter, the features of the present invention will be specifically described with reference to the embodiments shown in the drawings.

FIG. 1 shows a process of the method of the present invention, and FIG. 2 shows an outline of a concrete bag used in the present method.

The concrete bag 5 used in the present invention is a bag having a predetermined strength so as not to break when filled with concrete. That is, the concrete bag 5
At the lower end, a flat bottom plate 5a is provided, and the peripheral wall 5b is formed of a foldable bag-shaped material. Surrounding wall 5b
Is made of a material that can seal off the water so that groundwater does not infiltrate into the inside, and that can adhere to the inner wall of the casing 2 and prevent infiltration of groundwater into the pit bottom. As such a material, for example, a rubber sheet or a plastic sheet containing cloth is desirable, and it is assumed that the material has a strength enough to withstand filling with concrete as described above.

The concrete bag 5 has such a capacity that the peripheral wall 5b can be in close contact with the inner wall of the casing 2 after the concrete is filled into the inside. In other words, when the concrete is filled, the peripheral wall 5b expands to have a size that can strongly adhere to the inner wall of the casing 2. And it is a matter of course that the capacity can be filled with concrete having a sufficient depth in the vertical direction so that a predetermined bottom concrete thickness can be secured.

Further, the bottom plate 5a of the concrete bag 5 is a plate-like body made of, for example, metal or wood, and is inserted into the shaft 1 so as to land on the bottom of the pit or float on the mud near the pit. Play a role for. On the other hand, the peripheral wall 5b is fastened by bolts and nuts 5c as shown in FIG. 2 (c) (an enlarged sectional view of a portion surrounded by a dashed line in FIG. 2 (a)). Therefore, the peripheral wall can be folded up and down with respect to the bottom plate 5a, and even if groundwater is accumulated in the shaft 1, the bottom plate 5a can be placed on the pit bottom or floated on muddy water, and the peripheral wall 5b portion It can always be set up. Instead of the bolts and nuts 5c, the bottom plate 5a and the peripheral wall 5b may be integrated by rivets, an adhesive, sewing, or the like.

In the center of the upper end of the concrete bag 5, a connection port 5d for injecting concrete and an exhaust port 5e for releasing air are provided.
Is provided. A concrete supply pipe 6 is connected to the connection port 5d, and an air release pipe 7 is connected to the exhaust port 5e.
The lower end of the concrete supply pipe 6 is inserted into the connection port 5d as shown in FIG. 2 (d), and the periphery thereof is tightened up by a fastener 6a such as a wire or a hose band and connected to the concrete bag 5. On the other hand, the air bleeding pipe 7 uses a hose or the like, and a pipe is provided at the lower end thereof, which is inserted into the exhaust port 5e and connected by a fastener. The concrete supply pipe 6 and the air release pipe 7 are connected to the concrete bag 5 on the ground 8 in advance, and are integrally inserted into the shaft 1.

Here, unnecessary air in the concrete bag 5 generated by the filling of the concrete, if mixed with the concrete and hardened as it is, may cause a cavity of the concrete later, so that it is necessary to sufficiently discharge the air. On the other hand, since the air vent pipe 7 is provided, even if air is mixed in when filling the concrete, it can be discharged, and there is no trouble such as hollowing of the concrete. In addition, concrete bag 5 in groundwater 3
, The peripheral wall 5b is crushed by the water pressure, so that the air hardly accumulates in the concrete bag 5.

 Next, the method of the present embodiment will be described sequentially following each step.

FIG. 1 (a) shows a state where earth and sand 9 remain on the inner wall and the bottom of the casing 2 after the shaft 1 is excavated by the same method as described in the section of the prior art. And
Groundwater 3 has penetrated into the casing 2 and the pit bottom is submerged.

FIG. 1 (b) shows a casing cleaner 4 inside the shaft 1.
Is inserted to cut off the earth and sand attached to the inner wall of the casing 2 and level the bottom of the pit.

FIG. 1 (c) shows that after cleaning the inner wall and the bottom of the shaft 1, the concrete bag 5 is lowered to the bottom together with the concrete supply pipe 6 and the air release pipe 7, and the fresh concrete C is transferred from the concrete supply pipe 6 to the concrete bag 5. Indicates the filling operation.

Further, FIG. 1 (d) shows that the concrete bag 5 is filled with ready-mixed concrete C, the concrete bag 5 is brought into close contact with the casing 2, and the concrete bag 5 is made watertight to stop the watertight concrete.
Shows the state forming 10.

As described above, in the method of the present invention, after removing the residual soil in the casing 1 and leveling the undulation of the pit, the concrete bag 5 is settled on the pit, and the concrete bag 5 is placed inside the concrete bag 5 from the ground 8. Filling with ready-mixed concrete C,
The concrete bag 5 can be set in a watertight state by inflating the concrete bag 5 and bringing it into close contact with the pit wall.

For this reason, the ready-mixed concrete C is placed in the concrete bag 5
Is isolated from the outside world, so that the properties of concrete are not impaired by water or mud. In addition, since there is no separation from the aggregate particles, the structure after hardening of the concrete can maintain the solidity, and the effect of the waterproof concrete 10 can be enhanced. After completion of the bottom plate, there is no need to make repairs for flooding or water leakage, so that the water stoppage can be completed with low cost and simple work.

FIG. 3 shows another embodiment, in which the concrete bag 5 is formed in a bag shape and the bottom plate 5a in the above embodiment is not provided. Since the concrete bag 5 is required only to be able to be filled with fresh concrete C as its function and to be in close contact with the inner periphery of the casing 2 and to stop the water by expansion, even if it is made into a bag shape, it does not hinder the formation of the bottom plate. Can be used.

As shown in the figure, a concrete supply pipe 6 and an air release pipe 7 are connected to the concrete bag 5 and inserted into the shaft 1 in a deflated state as shown in FIG. When the concrete bag 5 is in the shape of a bag as described above, there is no obstacle such as interference with the inner wall of the casing 2 as compared with the case where the bottom plate 5a is provided, and the operation is simplified. Further, after the concrete bag 5 has landed on the bottom of the pit as shown in FIG. 3B, the fresh concrete C is filled and the concrete bag 5 is expanded and stopped at the bottom of the pit as in the case of the above embodiment. The water concrete 10 can be formed as a bottom plate. in this case,
Compared to the case where the bottom plate 5a is provided, the concrete bag 5
Since it is in the shape of a bag, it can be landed following the bottom of a well and a good bottom can be obtained.

Further, if the concrete bag 5 is simply formed as a bag-like material, the production is simplified as compared with the case where the bottom plate 5a is provided, which is advantageous in terms of cost. Further, since the weight is reduced, the burden on the operator is reduced.

〔The invention's effect〕

In the present invention, the waterproof cement is formed by press-fitting ready-mixed concrete into a concrete bag, so that the cement paste is not affected by the groundwater, there is no separation from aggregate grains, and the structure of the hardened cement body is not changed. Can be kept solid.

Moreover, since the performance of concrete is not hindered by mixing with groundwater, the function of waterproofing concrete is fully exhibited. In addition, since the occurrence of latencies is small and there is no need to inject a chemical solution for ground improvement, the operation is simple at low cost, and the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a view showing each step of the method of the present invention, FIG. 2 is a schematic view of a concrete bag used for performing the method of the present invention, and FIG. FIG. 4 is a view schematically showing a conventional method. 1: shaft, 2: casing 3: groundwater, 4 casing cleaner 5: concrete bag 5a: bottom plate, 5b: peripheral wall 5c: bolt and nut, 5d: connection port 5e: exhaust port 6: concrete supply pipe, 6a: fastening tool 7 : Vent pipe 8: Above ground, 9: Earth and sand 10: Waterproof concrete C: Fresh concrete

Claims (1)

(57) [Claims] 1. A concrete bag in which a concrete supply pipe is connected to an air release pipe is settled on the bottom of a shaft, and ready-mixed concrete is supplied from the concrete supply pipe to the concrete bag in a sealed state against water. Filling the concrete bag with the inner wall of the shaft by inflating the concrete bag by filling, and solidifying the filled concrete to form a bottom plate for stopping water at the shaft shaft, thereby forming a bottom of the shaft.