JPH1122373A - Building method for arrival or starting manhole in advancing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To build a manhole without building timbering for earth retaining. SOLUTION: When an impermeable impervious layer 12 is formed in a given depth position in a ground 10 of the an arrival manhole building schemed ground, a penetration work of a casing 14 is effected from the ground side. A casing 14 excavates earth in water and excavation is effected as excavated earth is discharged to an external part and when occasion needs, the casing 14 is rotational driven. When the tip of the casing 14 reaches the impervious layer 12, the surface side of the impervious layer 12, the surface side of the impervious layer 12 is excavated by approximate 1 m to prevent inflow of underground water to the casing 14. Water in the casing 14 is discharged. Thereafter, a manhole forming member is arranged in the casing 14 and the casing 14 is pulled out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a reaching or starting human hole in a propulsion method.

[0002]

2. Description of the Related Art When laying an underground conduit such as a sewer, the laying position may be deeper due to, for example, a crossing point of a river or a relationship with an underground object. For the construction work of the pipeline under such conditions, a propulsion method is usually employed.

[0003] When laying a pipeline in propulsion work, the pipeline is propelled from the starting manhole to the reaching manhole.
In such a propulsion method, a manhole structure is constructed using a secondary product of concrete.

[0004] In this case, as a method of constructing a human hole, a method for constructing a human hole is carried out from below by forming a human hole forming member divided into blocks after excavating the ground to a predetermined depth by providing a support for earth retaining. The method of stacking and building is generally adopted.

[0005] However, such a method for constructing a human hole has the following technical problems.

[0006]

That is, according to the above-described method for constructing a human hole, when the excavation depth becomes large, it takes time and effort to erection and removal of the shoring, and it is necessary to perform a deep underground stacking operation. Therefore, the working environment is not good.

[0007] Further, if the support is removed when the support is removed, there is a concern that the impact or vibration at that time may have an adverse effect on the constructed human hole structure and the surrounding ground.

[0008] The present invention has been made in view of such conventional problems, and an object of the present invention is to eliminate the need for shoring for earth retaining and adversely affect the surrounding ground. It is an object of the present invention to provide a method for constructing a reaching or starting human hole in a propulsion method in which the number of people is extremely reduced.

[0009]

In order to achieve the above object, the present invention relates to a method for constructing a reaching or starting manhole in a propulsion method, wherein the manhole is impermeable as required in the ground at the construction position of the manhole. Forming the impermeable layer, excavating the ground from the ground, and penetrating a casing whose lower end reaches the impermeable layer, and inserting and installing a human hole forming member having a closed lower end inside the casing. The step and the step of performing the protective work outside the human-hole forming member after the casing is pulled out while rotating the casing are sequentially performed. According to this configuration, earth retaining can be performed by the casing, and thus it is not necessary to install earth retaining supports associated with excavation. In addition, penetration of casing, pulling out,
Work such as insertion and installation of a member for forming a human hole can be performed from the ground side, so that work is not performed under adverse environmental conditions. Furthermore, when the casing is pulled out, it is performed while rotating, so that the influence on the surrounding ground and the constructed human hole is extremely reduced. In the step of penetrating the casing,
Water may be injected into the casing to perform underwater excavation, and the water in the casing may be drained before inserting and installing the human hole forming member. When such a configuration is adopted, the casing and the water injected into the casing can counter the surrounding earth water pressure, so that a deeper human hole can be constructed. The water impermeable layer can be formed by ground improvement by a deep mixing method or the like. When this configuration is adopted, the formation of the impermeable layer can be relatively easily performed from the ground side. In the present invention, a loading load can be applied to the human-hole forming member before the casing is pulled out. The loading load in this case is performed by, for example, pouring water into the human hole forming member, and if the loading load is applied to the human hole forming member, the negative pressure and buoyancy generated when the casing is pulled out are reduced. Thus, the human hole forming member can be stabilized.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 6 show an embodiment of a method for constructing a reaching or starting human hole in the propulsion method according to the present invention.

The construction method shown in FIG. 1 shows a case where the present invention is applied to a reaching manhole. When constructing a reaching manhole, first, as shown in FIG. An impermeable impermeable layer 12 is formed at a predetermined depth position in the ground 10 at the construction site.

The size of the water-impervious layer 12 is formed to be larger than the diameter of a casing 14 described later, and its thickness is set to, for example, about several meters. This impermeable layer 12
To form the ground, for example, as shown in the figure, the injection pipe 13 penetrates into the ground from the ground, and a powder or liquid consolidating material is sprayed from the tip side of the injection pipe 13 to perform the ground improvement. Can be formed.

The method of ground improvement is not limited to the method shown in FIG. 1, and may be, for example, a deep mixing method. In addition, when the properties of the ground 10 are good, the impermeable layer 12 does not necessarily need to be formed, and may be provided as necessary in consideration of the properties of the ground 10. When the formation of the water-blocking layer 12 is completed, the casing 14 is penetrated from the ground side as shown in FIG.

The casing 14 has, for example, a diameter of 2
m, while being guided by a guide 15 installed on the ground, filling the inside with water, excavating earth and sand underwater, and discharging the excavated earth and sand to the outside,
If necessary, the casing 14 is rotationally driven to reduce friction between the surrounding earth and sand.

If the properties of the ground 10 are very poor when the casing 14 is penetrated, for example, the ground in the area where the casing 14 is to be penetrated may be improved with lime or the like, or the ground 10 may be used. If the properties are good, the drying may be performed without injecting water into the casing 14.

When the tip of the casing 14 reaches the impermeable layer 12, the surface of the impermeable layer 12 is dug about 1 m to prevent groundwater from flowing into the casing 14. Next, as shown in FIG. 3, the submersible pump 16 is installed in the casing 14, and the water in the casing 14 is discharged.

When water is discharged from the casing 14,
As shown in FIG. 4, a bottom concrete layer 17 having a thickness that allows the casing 14 to be pulled out is formed on the bottom of the casing 14 as necessary.

Then, the human hole forming member 18 is suspended and installed in the casing 14. This human hole forming member 18
It has a bottom portion 18a and a cylindrical wall 18b integrally formed on the outer peripheral edge of the bottom portion 18a, and has a closed-bottom cylindrical shape with a closed lower end and an open upper end.

Such a human hole forming member 18 is sold as a secondary product of concrete and is called a uni-hole. In the case of a reaching manhole, the manhole forming member 18 needs a space for dismantling and removing the head of the arriving propulsion machine. Therefore, the inner diameter of the cylindrical wall 18b is, for example, 1.5 mm.
Use a material of about m.

When the installation of the human hole forming member 18 is completed, the casing 14 is pulled out as shown in FIG. In this case, prior to the operation of pulling out the casing 14, water is injected into the human hole forming member 18 to apply a load.

When the casing 14 is pulled out,
As the casing 14 is rotated, voids formed on the outer periphery of the human hole forming member 18 due to withdrawal of the casing 14 are filled with a solidifying agent such as cement bentonite via an injection pipe 20.

When the voids are filled with such a solidifying agent, the collapse of the surrounding ground due to the voids can be prevented. Further, when the casing 14 is pulled out while being rotated, the friction between the casing 14 and the ground 10 is reduced, so that the pulling out becomes easy and the influence on the surrounding ground is greatly reduced.

When the removal of the casing 14 is completed, as shown in FIG.
The wall body 22 communicating with the ground is formed, and the reach protection member 24 is formed outside the human hole forming member 18.

The reaching protection work 24 is performed by injecting an injection pipe 26 into the ground 10 from the ground side and injecting a chemical solution. When the reaching protection work 24 is formed, the construction of the reaching manhole is completed. I do.

According to the method for constructing the reaching manhole constructed as described above, earth retaining can be performed by penetrating the casing 14, so that it is not necessary to install an earth retaining support accompanying the excavation. Since there is no earth retaining support, the amount of excavated earth and sand is reduced by that much.

Further, the casing 14 is penetrated and pulled out,
Work such as insertion and installation of the human hole forming member 18 can be performed from the ground side, so that work is not performed under adverse environmental conditions.

Furthermore, since the casing 14 is pulled out while rotating, the influence on the surrounding ground and the constructed manhole is extremely reduced.

Further, in the case of this embodiment, the impermeable layer 12
Is formed by ground improvement by a deep mixing method or the like, so that the impermeable layer 12 can be formed relatively easily by work from the ground side.

Further, in the case of the present embodiment, before the casing 14 is pulled out, a water load is applied to the human hole forming member 18 to apply a load, so that a negative pressure and a buoyancy generated when the casing 14 is pulled out. Thus, the human hole forming member 18 can be stabilized.

In the above-described embodiment, the case where the present invention is applied to the construction of the reaching manhole is illustrated. However, the present invention can also be applied to the construction of the starting manhole of the propulsion method.

[0031]

As described above in detail in the embodiments,
According to the construction method of the reaching or starting manhole in the propulsion method according to the present invention, the work associated with the installation and removal of the earth retaining shoring becomes unnecessary, and the human labor is reduced. The environment is improved and safety is improved.

Further, since the amount of excavated soil is reduced, the construction period is shortened and the cost is reduced. Further, the influence on the surrounding ground can be extremely reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a first step of a method for constructing an attainment manhole according to the present invention.

FIG. 2 is an explanatory cross-sectional view of a step performed subsequent to the step of FIG. 1;

FIG. 3 is an explanatory cross-sectional view of a step performed subsequent to the step of FIG. 2;

FIG. 4 is an explanatory cross-sectional view of a step performed subsequent to the step of FIG. 3;

FIG. 5 is an explanatory cross-sectional view of a step performed subsequent to the step of FIG. 4;

FIG. 6 is an explanatory cross-sectional view of a step performed subsequent to the step of FIG. 5;

[Explanation of symbols]

 Reference Signs List 10 ground 12 impermeable layer 14 casing 16 submersible pump 18 human hole forming member 24 reaching protection

Claims (4)

[Claims] 1. A method for constructing a reaching or starting manhole in a propulsion method, comprising the steps of: forming an impermeable impermeable layer in the ground at a position where the manhole is constructed, if necessary, excavating the ground from the ground A step of penetrating a casing whose lower end reaches the impermeable layer while inserting and installing a human hole forming member having a closed lower end inside the casing; and And a step of performing an arrival protection work outside of the hole forming member in order. 2. In the step of penetrating the casing, water is injected into the casing to perform underwater excavation, and the water in the casing is drained before inserting and installing the human hole forming member. 2. A method for constructing a reaching or starting human hole in the propulsion method according to claim 1. 3. The method according to claim 1, wherein the water-impervious layer is formed by ground improvement by a deep mixing method or the like. 4. The method according to claim 1, wherein a load is applied to the human hole forming member before the casing is pulled out.