JP3721460B2 - How to start a shield machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starting method for a shield machine.
[0002]
[Prior art]
When a large space such as an expressway is formed in the ground, there is a limit to the size of the excavation with one shield machine.
Therefore, a method for constructing a large space using a normal shield machine has been developed. In this arrangement, a large number of tunnels are excavated adjacent to each other so as to surround the large space, and the interior of each tunnel is filled with concrete to construct portions corresponding to the ceiling and walls of the large space. After that, the inside is excavated while the surroundings are protected.
[0003]
In this case, as shown in FIG. 6, the tunnel b constructed by the shield machine a is configured to have a smaller dimension than the inner dimension of the tunnel machine a, and the periphery of the tunnel b is a layer of improvement material such as mortar having a considerable thickness. The method of surrounding with c is adopted.
In this way, the tunnel b surrounded by the improved material thickly is constructed in advance, and the adjacent shield machine a cuts off the improved material layer c part such as the mortar of the preceding tunnel b, in a slightly overlapping state. Build or advance along the improved material of the preceding shield. When a large number of tunnels b in which the improved material c portions overlap and are arranged in this manner, the adjacent portions are connected in the ground to construct an integral ceiling portion and wall portion.
[0004]
[Problems to be solved by the present invention]
In order to build the tunnel b surrounded by the improved material c thickly in the ground, it is necessary to make a large difference between the inner dimension of the shield machine a and the outer diameter of the tunnel b. The difference is the thickness of the improvement material layer c.
However, there are the following problems in a shaft for starting such a shield machine having a large dimensional difference.
<I> Although the vertical shaft is surrounded by a concrete wall, a hole through which the excavator penetrates is opened on one side. Until the time of intrusion, this opening is treated so as not to collapse. However, if the excavator penetrates to a certain distance, there is a risk that the soil and sand fluidized by groundwater will flow into the shaft from the part of the difference in size.
<B> Inflow of earth and sand should not occur even after penetration if the inner dimension of the opening established in the shaft and the outer dimension of the shield machine match exactly.
However, in reality, slight inclination and deformation of the fuselage occur during the excavation, and the dimensions of the two cannot be perfectly matched. Accordingly, there is a dimensional difference between the outer periphery of the machine body and the inner periphery of the opening, and it is inevitable that earth and sand from that portion will flow in after penetration.
<C> The above problem also occurs in the start shaft of a general shield machine. Especially when constructing a tunnel surrounded by an improved material layer as described above, the dimensions inside the shield machine are There is a large difference in dimensions with the tunnel outer periphery.
Therefore, it is extremely dangerous for earth and sand to flow in from the part of the dimensional difference after penetrating the shaft.
[0005]
The present invention has been made to solve the above-described conventional problems, and even when there is a large difference between the inner dimensions of the shield machine and the outer circumference of the tunnel, the shaft opening and the excavator are different. It is an object of the present invention to provide a starting method for a shield machine capable of avoiding the inflow of earth and sand into the shaft from the dimension difference and the dimension difference between the excavator and the outer periphery of the tunnel.
[0006]
[Means for Solving the Problems]
In order to solve the problems as described above, the start method of the shield machine according to the present invention is a start method in the case where there is a difference between the inner dimension of the shield machine and the outer periphery of the tunnel. dimensional difference between the parts and the excavator is closed by members of flexible mounted inward Shaft opening, dimensional difference between shafts opening and the tunnel circumference, directly inward Shaft opening It is characterized by a starting method of a shield machine that is closed by integrating a rigid closing member attached in contact with the outer periphery of the tunnel and a steel segment provided in a part of the tunnel .
Further, the start method of the shield machine of the present invention is a start method in the case where there is a difference between the inner dimension of the shield machine and the outer diameter of the tunnel, and the inner periphery of the shaft opening is flexible. Is attached, and the part of the dimensional difference between the shaft opening and the excavator is closed, and when the tail end of the shield excavator reaches the vicinity of the opening, the entire circumference of the shaft opening and the outer periphery of the tunnel Rukoto be integrated closing member having a length that contacts protruding directly in a state in contact with the outer periphery of the tunnel towards the inside, the outer periphery of the steel segment having a inner end of the closure member to a portion of the tunnel Thus, the starting method of the shield machine is performed by closing the dimensional difference between the shaft opening and the outer periphery of the tunnel.
[0007]
[Embodiments of the present invention]
Embodiments of a starting method for a shield machine according to the present invention will be described below with reference to the drawings.
[0008]
<A> Dimensional difference between the shaft opening and the excavator In a normal shield excavator, the inner dimension of the shield excavator 1 and the outer dimension of the tunnel 2 are substantially equal, and the shield excavator is installed through a slight interval. It is configured to slide out from the outer periphery of the tunnel.
However, the present invention is a starting method in the case where there is a large difference between the inner dimension of the shield machine 1 and the outer dimension of the tunnel 2 as described above.
In that case, the following triple occlusion member is required.
(1) A member that closes the space between the shaft opening and the outer periphery of the excavator.
(2) A member that closes the gap between the excavator and the outer periphery of the tunnel.
(3) A member that closes the gap between the shaft opening and the outer periphery of the tunnel.
Of the above triple blocking members, (1) and (2) are also required for starting a normal shield machine and are well known.
That is, {circle around (1)} (a member that closes the space between the shaft opening and the outer periphery of the excavator) is called an entrance packing 31, and a flexible member is attached to the entire inner periphery of the opening 3.
Moreover, (2) (member for closing the gap between the excavator and the outer periphery of the tunnel) is referred to as a tail seal 6 and is configured by attaching a flexible member to the entire inner periphery of the shield excavator.
[0009]
<B> A member that blocks the dimensional difference between the excavator and the tunnel.
Only in the special start where the dimensional difference between the inside of the shield machine 1 and the outside of the tunnel 2 is large as in the present invention, the closing member shown in (3) is particularly required.
For this purpose, a tunnel blocking member 5 is attached to the entire circumference of the shaft opening 3.
The tunnel closing member 5 is constituted by a plate body having a length in contact with the outer periphery of the tunnel 2 and having a high rigidity (low flexibility). The plate body is configured to be slidable, for example, to provide a length adjusting function.
[0010]
When the tail end of the shield machine reaches the vicinity of the opening, the tunnel blocking member 5 is projected inward so as to avoid the machine and directly contact the outer periphery of the tunnel 2.
In this way, by bringing the inner end of the tunnel closing member 5 into contact with the outer periphery of the tunnel 2, the dimensional difference between the opening 3 and the outer periphery of the tunnel 2 is blocked, and water tightness can be secured.
Since this tunnel blocking member 5 covers the dimensional difference between the opening 3 and the tunnel 2, the outer shape is the same as or larger than the inner shape of the opening 3, and the inner shape is the outer side of the tunnel 2. The shape is the same.
[0011]
<C> Advancement of the excavator.
The opening 3 of the shaft is opened with a size slightly larger than the outer shape of the shield machine 1, and the outer earth and sand are hardened by chemical injection or the like.
When approaching, a small number of segments are assembled in the shaft, and the reaction force is applied to the end face of the tunnel 2 formed by the segments by the jack inside the shield machine 1 and enters the soil from the opening 3.
At that time, earth and sand entering from the space between the inside of the opening 3 and the outside of the excavator 1 can be blocked by the flexible entrance packing 4 attached to the entire circumference inside the opening 3. .
[0012]
<D> Installation of steel ring.
When the tip of the tunnel in which the segment is assembled reaches the vicinity of the opening 3, only one steel ring is installed at the tail end of the segment.
After that, the usual segment is assembled.
[0013]
<E> Installation of tunnel blocking member.
When the tail end of the shield machine 1 reaches the vicinity of the opening 3, the tunnel blocking member 5 is attached in a state of projecting inward using the outer wall of the opening 3 or the like. Since this tunnel blocking member 5 is constituted by a highly rigid plate having a length that contacts the outer periphery of the tunnel 2, the tunnel blocking member 5 cannot be attached if the excavator 1 is present.
Therefore, this tunnel blocking member 5 avoids the position of the excavator 1 when the tail end of the shield excavator 1 approaches the vicinity of the opening 3, and the outer periphery of the steel segment that is directly part of the tunnel 2. Projecting inward while in contact with
Since the inner shape of the tunnel blocking member 5 is the same as the outer shape of the tunnel 2, the inner end is contacted and fixed to the outer periphery of the steel segment of the tunnel 2 by welding or the like. It is possible to ensure water tightness by closing the dimensional difference.
[0014]
<F> Filling with mortar.
In this state, the excavator 1 is advanced.
Then, a filling material such as mortar is filled in the space surrounded by the opening 3, the tunnel closing member 5, the tail seal 6, and the outer periphery of the tunnel 2.
Therefore, although the dimensional difference between the opening 3 and the tunnel 2 is large, the filler is completely prevented from flowing into the shaft by the highly rigid closing member 5.
Therefore, in the subsequent excavation, the outflow into the shaft does not occur.
[0015]
[Effect of the present invention]
Since the starting method of the shield machine of the present invention is as described above, the following effects can be obtained.
<I> When there is a large difference between the inner dimensions of the shield machine and the outer circumference of the tunnel, the risk of inflow of earth and sand into the vertical shaft at the time of starting was a problem.
However, the method of the present invention employs a method in which the space between the opening and the tunnel is closed by a highly rigid closing member to form a certain enclosed space.
Therefore, with a very simple structure, it is possible to start safely from the shaft while completely preventing inflow of earth and sand into the shaft.
<B> Since the start method is simple as described above, it is possible to easily cope with any shape of the shield machine.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a start state of a shield in which a dimensional difference between a shield machine and a tunnel is formed.
FIG. 2 is an explanatory diagram of an embodiment of a method for starting a shield machine according to the present invention. FIG. 3 is an explanatory diagram of an embodiment of a method for starting a shield machine according to the present invention. FIG. 5 is an explanatory diagram of an embodiment of a method for starting a shield machine according to the present invention. FIG. 6 is an explanatory diagram of a tunnel construction method for constructing a thick ground improvement layer around the tunnel.

Claims (2)

It is a starting method when there is a difference between the inner dimension of the shield machine and the outer diameter of the tunnel,
The dimensional difference between the shaft opening and the excavator is blocked by a flexible member attached inward to the shaft opening,
Dimensional difference between shafts opening and the tunnel circumference, integral with the closing member rigid mounted in a state in contact with the outer periphery of the direct tunnel towards the inside pit opening, and the steel segment is provided in a part of the tunnel To be blocked by
How to start a shield machine. It is a starting method when there is a difference between the inner dimension of the shield machine and the outer diameter of the tunnel,
A flexible member is attached to the entire inner periphery of the shaft opening, and the dimensional difference between the shaft opening and the excavator is closed,
When the tail end of the shield machine reaches the vicinity of the opening, the entire length of the shaft opening is in direct contact with the outer periphery of the tunnel with the closing member having a length contacting the outer periphery of the tunnel facing inward. Project
By Rukoto to integrate the inner end of the closure member on the outer periphery of the steel segment is provided in a part of the tunnel,
A method for starting a shield machine that closes the dimensional difference between the shaft opening and the outer periphery of the tunnel.

Images