JPH08246782A - Removal method of start pit wall with shield starting - Google Patents

Abstract

PURPOSE: To remove a start pit wall simply and surely, besides in a short time by crushing it with a bursting charge and to make the cost of construction inexpensive. CONSTITUTION: In the case where a shield starting pit is constructed by a continuous wall 2 (underground continuous wall), a section corresponding to a peripheral part of a shield starting range 5 of this continuous wall 2 is subjected to core boring, whereby it is cut into slitting by the succession of this core. In addition, a shield starting range lower part is slit-cut likewise in the cross direction, installing an opening part 9 therein, and a bursting charge hole 10 is made in the remaining shield starting range 5 at a required pitch. In this constitution, those of charging and blasting are carried out from a position being nearer to the opening part 9 at a lower part out of this bored charging hole 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing a starting pit wall accompanying the start of a shield in a shield construction method for tunnel construction.

[0002]

2. Description of the Related Art A shield starting shaft in a shield construction method may be constructed not only by a steel material such as H-section steel or sheet pile with a steel sheet pile but also by a continuous wall (underground continuous wall).

As is well known, such a continuous wall (underground continuous wall) is constructed by suspending a rebar cage in a drilled laterally long hole and placing concrete by leaving the joint of the rebar cage to form a reinforced concrete preceding element. Constructed, then drilled, reinforced cage placement, concrete pouring, constructing a trailing element that connects to the leading element through the joint, and a continuous reinforced concrete with such a leading and trailing element connection. The wall is built underground.

A start pit having such a connecting wall as a surrounding wall can be constructed for a large depth.

In order to install a shield machine in the start pit and start it, it is necessary to remove the start pit wall in that part, but conventionally, almost all of the outer periphery of the shield start range is slit by core boring. After cutting, it was broken little by little by a hitting machine such as a breaker.

[0006]

As described above, the conventional removal method using a hitting machine such as a breaker requires time and labor, requires a long process, and is expensive. In particular,
The deep concrete wall has a high concrete strength of 800
~1,000 kgf / cm ² and the destruction is difficult.

The object of the present invention is to eliminate the inconveniences of the above-mentioned conventional examples, and to carry out the method easily, reliably and in a short time.
It is to provide a method for removing the starting pit wall that accompanies the start of the shield, which is inexpensive.

[0008]

In order to achieve the above-mentioned object, the present invention, when the shield starting shaft is constructed by a connecting wall (underground continuous wall), uses a portion corresponding to the outer peripheral part of the shield starting range of the connecting wall as a core. Boring, slitting by the continuation of this core, further slitting the lower part of the shield starting range in the same way in the lateral direction to provide an open part, and blasting charging holes at the required pitch within the remaining shield starting range Then
The gist of the present invention is to carry out the charging and blasting from a position near the lower open portion of the punched charging holes.

[0009]

According to the present invention, the connecting wall in the shield starting range is crushed by blasting and removed in a short time, and the opening provided at the bottom of the shield starting range by the slit facilitates crushing by this blasting. can do.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 10 are a front view and a longitudinal side view of each step showing one embodiment of a method of removing a starting pit wall according to the starting of a shield according to the present invention.

In the figure, 1 is a shield starting pit, 2 is a connecting wall (underground wall) which constructs the shield starting pit 1, and 3 is a shield machine installed in the shield starting pit 1. Further, in preparation for the start of the shield machine 1, a ground improvement 4 is applied to the outside of the connecting wall 2 by a freezing method or a chemical injection method. Further, the hatched portion of the connecting wall 2 indicates the shield starting range 5.

As shown in FIGS. 2 and 3, a portion corresponding to the outer peripheral portion of the shield starting range 5 is core-bored, and a slit 7 is formed by the continuation of the core 6 to cut. At this time, the core 6 has a remaining wall portion of about 10 cm left on the outer wall portion as shown in FIG.

Further, as shown in FIGS. 5 and 6, a lower portion is core-bored in the shield starting range 5, and a slit 8 is cut in the lateral direction by the continuation of the core 6 to provide an open portion 9. In this case as well, the core 6 leaves a residual wall portion of about 10 cm on the outer wall portion, so that the open portion 9 also leaves a residual wall portion of about 10 cm on the outer wall portion as shown in FIG.

As shown in FIGS. 7 and 8, blasting charge holes 10 are punched at a pitch of 30 to 50 cm in the remaining shield starting range 5.

The charging and blasting are carried out from a position near the lower opening of the charging hole 10 thus drilled. Then, as shown in Fig. 11, a small amount (100g to 200g) of the explosive is dispersed in a small explosive 11 of about 10g. In the figure, 12 is a blasting machine.

[0016]

As described above, the method of removing the starting pit wall associated with the starting of the shield according to the present invention can be performed easily and reliably in a short time by crushing using blasting, and the construction cost is also low. It is inexpensive.

[Brief description of drawings]

FIG. 1 is a front view of a front stage state showing one embodiment of a method of removing a starting pit wall according to the starting of a shield according to the present invention.

FIG. 2 is a vertical cross-sectional side view showing a front stage state of an embodiment of a method of removing a starting pit wall according to the present invention when a shield is started.

FIG. 3 is a front view of a first step showing an embodiment of a method of removing a starting pit wall associated with starting of a shield according to the present invention.

FIG. 4 is a vertical cross-sectional side view of a second step showing one embodiment of the method of removing the starting pit wall associated with the starting of the shield according to the present invention.

FIG. 5 is a front view of a third step showing one embodiment of the method of removing the starting pit wall associated with the starting of the shield according to the present invention.

FIG. 6 is a vertical cross-sectional side view of a third step showing an embodiment of the method for removing the starting shaft wall associated with the starting of the shield according to the present invention.

FIG. 7 is a front view of a fourth step showing an embodiment of the method of removing the starting pit wall associated with the starting of the shield according to the present invention.

FIG. 8 is a vertical cross-sectional side view of a fourth step showing an embodiment of the method for removing the starting shaft wall associated with the starting of the shield according to the present invention.

FIG. 9 is a front view of a fifth step showing one embodiment of the method of removing the starting pit wall associated with the starting of the shield according to the present invention.

FIG. 10 is a partially enlarged vertical cross-sectional side view of a fifth step showing an embodiment of a method of removing a starting pit wall associated with starting of a shield according to the present invention.

FIG. 11 is an enlarged vertical cross-sectional side view of a charging hole portion showing an embodiment of a method of removing a starting pit wall associated with starting of a shield according to the present invention.

[Explanation of symbols]

 1 ... Shield launch pit 2 ... Wall 3 ... Shield machine 4 ... Ground improvement 5 ... Shield launch range 6 ... Core 7, 8 ... Slit 9 ... Open part 10 ... Charge hole 11 ... Explosive 12 ... Blaster

Front page continuation (72) Inventor Takashi Takano 1-3-8 Moto-Akasaka, Minato-ku, Tokyo Inside Kashima Construction Co., Ltd. Tokyo Branch (72) Inventor Ryuji Matsumoto 1-3-8 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. in Tokyo Branch (72) Inventor Kazuo Usui 1-3-8 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. in Tokyo Branch (72) Inventor Masatoshi Ishida 1-chome, Moto Akasaka, Minato-ku, Tokyo No. 2-7 Kashima Construction Co., Ltd.

Claims (1)

[Claims] 1. When the shield starting shaft is constructed by a continuous wall (underground continuous wall), core boring is performed on a portion corresponding to the outer peripheral portion of the shield starting range of the continuous wall and slit cutting is performed by the continuation of the core. The lower part of the shield starting area is slit similarly in the lateral direction to provide an opening, and the blasting charging holes are punched to the required pitch in the remaining shield starting range. A method for removing the starting pit wall that accompanies the start of the shield, which is characterized by charging and blasting from a position close to.