JP2000220165A - Boring device for underground continuous wall construction ditch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boring device for underground continuous wall construction ditch that can bore underground continuous wall construction ditch by boring the directly under portion thereof without the removal of an underground obstacles. SOLUTION: The boring device is formed such that one of a chain cutter having an endless chain 3 being substantially crossed linearly over between both the upper and lower portions of a cutter post 4 and a chain cutter 5a1 having a part between both the upper and lower end portions spread over in the horizontal direction is selectively secured changeably to a traveling carriage 6. In this manner, the directly under execution can be done without the necessity of removing underground obstacles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground continuous wall forming groove excavation device for excavating a continuous groove for forming a continuous wall for water stoppage or the like in the ground.

[0002]

2. Description of the Related Art As shown in FIGS. 18 and 19, a traveling bogie (for example, a crawler type crane) has conventionally been used as a device for excavating a trench for forming an underground continuous wall (hereinafter referred to as "conventional device 51"). A chain type cutter 53 is vertically attached to a base machine 52, and in a state where the cutter 53 is inserted into the ground, the cutter 53 is rotated in the white arrow direction in FIG. It is known that a groove G having a constant width is continuously excavated in the ground indicated by oblique lines in the figure by moving the solid groove. A solidifying material such as cement milk is injected and solidified into the continuous groove G. An underground continuous wall is created (Japanese Patent Laid-Open No. 5-280043).
No., JP-A-5-280044).

[0003] The chain type cutter 53 includes a drive wheel (sprocket) 55 provided at an upper end of a cutter post 54 which is a vertically long box-shaped frame, and a guide wheel (idler) provided at a lower end of the cutter post 54. An endless chain 57 is stretched in a straight line between the chain 57 and a plurality of digging blades 58 provided on the outer peripheral side of the chain 57 to excavate the groove G. FIG. 20 shows a construction example using the cutter 53.

[0004]

In the above conventional apparatus 51, if there is an obstacle that cannot be removed from the surface of the ground to the depth to be excavated, for example, if there is an underground pipe, the obstacle is deeper than that part. Excavation is not possible under a certain obstacle. That is, since the chain type cutter 53 of the conventional device 51 has a linear shape, as shown in FIGS. If there is a pipe A, the cutter 53 interferes with the buried pipe A, so that it cannot proceed any further. in this case,
As shown in FIG. 20 (c), the cutter 53 can be excavated directly above the buried pipe A by shortening the cutter 53. After the cutter 53 is once pulled out to the ground, the cutter 53 is inserted again into the ground from the opposite side to the buried pipe A as shown in FIG. Advance. However, also in this case, as shown in FIG. 20 (e), the cutter 53 interferes with the buried pipe A and cannot proceed any further.
As a result, it is not possible to excavate immediately below the buried pipe A. Therefore, conventionally, when there is such an obstacle, it is necessary to remove the obstacle and then excavate to construct an underground continuous wall, which is troublesome. In addition, if the obstacle could not be removed, excavation immediately below it could not be performed.

[0005] In order to solve such problems in the prior art, the present invention provides an excavation device for a trench for forming an underground continuous wall which enables excavation immediately below an underground obstacle without removing the obstacle. It is intended to provide.

[0006]

According to a first aspect of the present invention, an endless chain having an excavating blade is provided between a top end and a bottom end of a cutter post. In the underground continuous wall formation groove excavation equipment, where the chain type cutter is inserted into the ground and rotated horizontally while rotating, excavating the continuous wall formation groove, the endless chain is attached to the cutter post. One of a chain-type cutter that is stretched in a substantially straight line between upper and lower ends, and a chain-type cutter that partially extends between the upper and lower ends in the horizontal movement direction,
It is configured as an excavation device for an underground continuous wall formation groove, which is selectively replaceably attached to the traveling vehicle.

According to such a configuration, if a chain-type cutter having a portion extending between the upper and lower ends in the horizontal movement direction is replaced, a portion directly below the underground obstacle is excavated by the projecting portion of the cutter. be able to. As a result, it is possible to excavate immediately below the underground obstacle without removing the underground obstacle and create an underground continuous wall.

According to a second aspect of the present invention, a chain type cutter having an endless chain having an excavating blade stretched between upper and lower ends of a cutter post is attached to a traveling carriage, and the chain type cutter is inserted into the ground. In the underground continuous wall formation groove excavation device for excavating the continuous wall formation groove in the ground by horizontally moving while rotating in a state where it is rotated, a part between the upper and lower ends of the chain type cutter is horizontally moved. It is configured as an excavation device for an underground continuous wall forming groove, which is provided with a telescopic mechanism for extending and contracting in a direction.

According to this structure, the extension mechanism is provided to extend a portion between the upper and lower ends of the chain type cutter so as to extend and contract in the horizontal movement direction. If the size of the portion is freely changed, the overhanging portion of the cutter can be used to excavate immediately below the underground obstacle. As a result, it is possible to excavate immediately below the underground obstacle without removing the underground obstacle and create an underground continuous wall. Further, in this case, it is not necessary to replace the heavy cutter or the overhanging portion, so that the working efficiency can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
It should be noted that the following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention. Here, FIG. 1 is a front view showing an entire configuration of an excavation device for a trench for forming an underground continuous wall according to Embodiment 1 of the present invention, FIG.
3 is an enlarged view taken along the line II in FIG. 1, FIGS. 3 (a) to 3 (d) are explanatory views showing an example of a projecting shape of the chain type cutter of the apparatus according to the first embodiment, and FIG. 4 is a detail of the chain type cutter. It is a structural view, (A) is a front view, (B) is a partial enlarged view, (C) is an enlarged view taken along the line II-II of (B), and (D) is a perspective view around a link pin. Also, FIG.
(E) is an explanatory view showing one construction example by the apparatus according to the first embodiment, and FIGS. 6A to 6C are explanatory views showing another construction example by the apparatus according to the first embodiment. 7 is a partial detailed structural view of a cutter-type chain when the cylinder of the excavator for excavating an underground continuous wall forming groove according to Embodiment 2 of the present invention is contracted, (a) is a front view, and (b) is IIIa. -II
FIG. 8 is a partial detailed structural view of the cutter-type chain when the cylinder of the excavator for excavating the underground continuous wall forming groove according to the second embodiment of the present invention is extended, and FIG. 8 is a front view. FIG. 9B is a view taken along the line IIIb-IIIb, and FIGS.
FIGS. 14A and 14B are partial detailed structural diagrams according to modifications of FIGS. 7 and 8, respectively, wherein FIG. 14A is a front view, and FIG.
To IX-IX line, FIGS. 15 (a) to 15 (f) are explanatory diagrams showing examples of construction by the apparatus according to the second embodiment of the present invention, and FIG. 16 is a diagram according to the third embodiment of the present invention. FIG. 17 is a front view showing an entire configuration of an excavator for a trench for forming an underground continuous wall, and FIG. Hereinafter, some embodiments of the present invention will be described with reference to these drawings.

(Embodiment 1) As shown in FIG. 1 and FIG. 2, an excavation device (hereinafter, referred to as "excavation device 1") for an underground continuous wall forming groove according to an embodiment 1 is an excavation blade. A chain type cutter 5a1 in which an endless chain 3 having 2a is stretched between upper and lower ends of a cutter post 4.
Is attached to the traveling trolley 6, and this chain type cutter 5a
1 is inserted in the ground indicated by oblique lines in the figure, and the cutter 5a1 is horizontally moved while rotating in the direction of the white arrow in the figure to excavate the continuous wall forming groove G in the ground. This is the same as the conventional example. However, in the present excavator 1, the chain type cutter 53 (see FIG. 1) in which the endless chain 3 is stretched substantially linearly between the upper and lower ends of the cutter post 4.
8 and FIG. 19) and a chain type cutter 5a1 in which a part between the upper and lower ends is extended in the horizontal movement direction (the traveling direction of the continuous groove G in the excavation plane). It differs from the conventional example in that it is replaceably attached to the traveling vehicle 6.

The chain-type cutter 5a1 has at least a part of a lower half protruding from an upper half. For example, as shown in FIG. 1, that is, as shown in FIG. 2A, the cutter post 4 is extended in parallel from near the center between the upper and lower ends to near the lower end. For this reason, in addition to the drive wheel (sprocket) 7 provided at the upper end of the cutter post 4 and the guide wheel (idler) 8 provided at the lower end, two more guide wheels 9 and 10 are provided. I have. Then, these drive wheels 7 and the guide wheels 8, 9,
10, the endless chain 3 is wound. The guide wheels 9 and 10 are rotatably attached to upper and lower portions of the tip side of the overhang 4a of the cutter post 4, respectively.
The overhanging portion 4a may be integrated with the cutter post 4, or may be configured to be detachable from the cutter post 4 using bolts, nuts, or the like. The overhang 4a is made as light as possible and has sufficient strength. The specific structure thereof may be a box structure, a truss structure, or any other structure.

However, the overhang 4a and the cutter post
In the upper boundary portion 4b with the endless chain 3, since the bending direction of the endless chain 3 is different from other portions and is valley-folded as viewed from the outer peripheral side, the guide wheel is connected to the endless chain 3 like the other portion which is mountain-folded. Cannot be provided on the inner peripheral side of the.
Therefore, in the present excavator 1, FIG. 3 and FIG.
As shown in (d), the link pins 3a of the endless chain 3 are protruded on both sides of the chain, and a guide rail 11 having a C-shaped cross section for guiding the protruding ends is formed at the upper boundary between the overhanging portion 4a and the cutter post 4. It is provided in the section 4b.

Also, instead of the chain type cutter 5a1, for example, a cutter post 4 as shown in FIG.
The cutter 5a2 gradually protrudes from the vicinity of the center between the upper and lower ends to the vicinity of the lower end, and from the vicinity of the lower end to the vicinity of the center between the upper and lower ends of the cutter post 4 as shown in FIG. Cutter 5a gradually overhanging
3, or a cutter 5a4 that gradually protrudes from near the upper end to near the lower end between the upper and lower ends of the cutter post 4, as shown in FIG. 3 (d).
In addition, each code | symbol in a figure is made to correspond to FIG. Among them, the chain type cutter 5a1 as shown in FIG.
In this case, two guide wheels are added as compared with the conventional device 51. However, in the chain type cutters 5a2 to 5a4 as shown in FIGS. A chain type cutter 5a4 as shown in FIG.
Then, the guide rail 11 as described above is unnecessary.
Further, it is conceivable to change the overhang shape of the cutter by increasing the number of guide wheels or the like, but it is not practical because the structure becomes complicated.

Hereinafter, an example of construction by the present excavator 1 will be described. First, when a chain type cutter 5a1 as shown in FIG. 1 or FIG.
As shown in (a), the underground continuous wall formation groove G is excavated by using the same chain type cutter 53 as in the conventional example up to the point immediately before the underground obstacle, for example, the buried pipe A. Then, FIG.
As shown in (b), the cutter 53 is extracted from the ground and replaced on the ground with, for example, the chain type cutter 5a1 of the first embodiment.

Then, as shown in FIG. 5C, the cutter 5a1 is used to excavate just below the buried pipe A. At this time, as shown in FIG. 5D, the cutter 5a1 is moved up and down as necessary. When the diameter of the buried pipe A is large and the overhang of the cutter 5a1 is insufficient,
As shown in FIG. 5 (e), the work may be excavated from the opposite side of the buried pipe A and wrapped from both sides.

When the chain type cutters 5a2, 5a3, 5a4 as shown in FIGS. 3 (b), (c), and (d) are used, FIGS. 6 (a), (b), (c) As shown in the figure below, everything under the buried pipe cannot be excavated, but it can cover most of the construction target. However, FIG.
Chain type cutters 5a2 and 5a3 as shown in (c)
In the case where is used, compared to the case where a chain type cutter 5a4 as shown in FIG. This is shown in FIGS. 6 (a), (b),
(C) I can understand it more easily.

As described above, according to the present excavator 1, if the chain type cutters 5a1 to 5a4, which are partially extended between the upper and lower ends in horizontal movement, are replaced by underground due to the extended portions of the cutters. It is possible to excavate just below the obstacle. As a result, without removing underground obstacles,
It is possible to excavate the area directly underneath to create an underground continuous wall.

In the first embodiment, the cutter 5
The whole of a1-5a4 was replaced, but the overhang portion 4a
Only one may be replaced. In this case, as described above, it is necessary to make the overhanging portion 4a detachable from the cutter post 4, but the weight of the replacement portion is reduced, so that the working efficiency can be improved.

(Embodiment 2) In the excavator 1 according to Embodiment 1, the chain type cutters 5a1 to 5a4 are used.
Alternatively, it is necessary to replace the overhanging portion 4a. However, since the overhanging portion 4a alone is considerably heavy as well as the cutter itself, the replacement is time-consuming. Therefore, in the second embodiment, such labor is omitted as much as possible. In other words, as shown in FIGS. 7 and 8, the excavator for excavating the underground continuous wall forming groove according to the second embodiment (hereinafter, referred to as “excavator 2”) has upper and lower ends of a chain type cutter 5 b. The excavating apparatus according to the above-described conventional example and the first embodiment is provided with a telescopic mechanism for extending a part between the telescopic parts so as to extend and contract in a horizontal movement direction (a traveling direction of the continuous groove G in the excavation plane). 1, the other configuration is the same as the excavator 1.

As shown in FIG.
For example, a fork-shaped member 15 is provided on the telescopic end sides of the cylinders 12 and 13 provided with the guide wheels 9 and 10 in a horizontal state.
It is rotatably mounted via. Cylinder 1
The fixed ends of the members 2 and 13 are attached to the cutter post 4 with bolts or the like. Therefore, the guide wheels 9 and 10 relatively move horizontally outward with respect to the cutter post 4 by the expansion and contraction of the expansion and contraction ends of these cylinders. That is, FIGS. 7 (a) and 7 (b) show the state in which the expansion and contraction ends of the cylinder are most contracted. The cutter 5b does not form any overhang. On the other hand, FIGS. 8 (a) and 8 (b) show a state where the telescopic end of the cylinder is the most extended, and at this time, the guide wheels 9 and 10 are outside the cutter post 4 and the cutter 5b
Form an overhang as in the excavator 1 described above. The cylinders 12 and 13 are connected to the cutter post 4
It is preferable that they are connected to each other by, for example, a connecting member 14 so that they do not relatively move between the cylinders. Further, the cylinder does not necessarily have to be in a horizontal state, and may be attached at an angle.

It is necessary to adjust the length of the endless chain 3 with the expansion and contraction of the expansion and contraction ends of the cylinders 12 and 13. Here, the adjustment is performed on the ground, but the height of the cutter post 4 may be adjusted instead. In that case, the height of the cutter post 4 may be automatically adjusted.

Although the cylinders 12 and 13 do not necessarily have the same expansion and contraction strokes, here, the guide wheels 9 and 10 are moved in parallel by the same stroke. By changing the strokes of both cylinders, various overhang shapes such as the cutters 5a1 to 5a4 shown in FIG. 3 can be realized.

Other modified examples are shown in FIGS. That is, FIGS. 9 and 10 show that the guide wheel 9 is directly pushed out of the cutter post 4 by the double cylinders 13 and 13 or is drawn into the cutter post 4 and is different from those shown in FIGS. A strong pressing force can be obtained, and a large stroke can be secured. In this case, a larger stroke can be obtained by using a two-stage cylinder. 11 and 12 show two-stage pulley 1
The guide wheel 9 is pushed or pulled in via the springs 13a and 13a and the spring 13b, so that the protrusion of the guide wheel 9 can be increased. 13 and 14 change the mounting direction of the cylinder 13 and change the three-stage pulley 13a,
The guide wheel 9 is pushed out or pulled in via the springs 13a, 13a and 13b, so that the guide wheel 9 can be further extended. FIG.
In each of the front views (a) of FIGS. 1 to 14, the spring 13 b is hidden by the guide wheel 9 and the like and is hardly visible, so that the description is omitted, but the mounting position of the spring 13 b is indicated by each arrow ( (B) As shown in FIG.

Hereinafter, a construction example using the present excavator 2 will be described. First, as shown in FIG. 15A, the underground obstruction, for example, the underground continuous wall forming groove G is cut by the cutter 5 b with the expandable ends of the cylinders 12 and 13 shortened to a point just before the buried pipe A. Excavate. Then, as shown in FIG. 15 (b), the cutter 5b is retracted once, pulled out to the ground, and the above-described adjustment of the chain length and the extension of the telescopic end of the cylinder are performed on the ground, whereby the cutter 5b is cut. To form a suitable overhang. Then, FIG.
As shown in FIG.
b is returned to the ground again, and the cutter 5b is used to excavate immediately below the buried pipe A as shown in FIG. At this time, the cutter 5b may be moved up and down as needed.
When the diameter of the buried pipe A is large and the overhang of the cutter 5b is insufficient, as shown in FIG.
Excavation is also performed from the opposite side of the buried pipe A, and lapping is performed from both sides. Finally, as shown in FIG. 15 (F), excavation just above the buried pipe A is completed to complete the construction of the water blocking wall.

As described above, the present excavator 2 is provided with the extension mechanism for extending a part between the upper and lower ends of the chain type cutter 5b so as to extend and contract in the horizontal movement direction. By the extension mechanism, the size of the overhang portion can be freely changed, and it is possible to excavate immediately below the underground obstacle. As a result, it is possible to perform construction immediately below the underground obstacle without removing the obstacle. Also, in this case, there is no need to replace the heavy cutter or overhang,
Work efficiency can be further improved.

In the second embodiment, it is assumed that the height of the cutter post 4 can be automatically adjusted. In such a case, the cutter 5b is placed on the ground during the excavation work. There is no need to extract. That is, in this case, in FIG. 15 (b), if the expansion and contraction force of the cylinder is weak, the cylinder is retracted once and the cylinder is extended at that position, so that the state shown in FIG. 15 (c) is obtained. , Excavation work can continue. As a result, even the work of adjusting the chain is eliminated, and the working efficiency can be greatly improved.

(Embodiment 3) In the excavating apparatus 2 according to the second embodiment, the cutters 5a1 to 5a1 in the excavating apparatus 1 according to the first embodiment are used for the upper boundary between the overhang portion of the cutter and the cutter post. Similarly to 5a3, a link pin 3a of the endless chain 3 and a guide rail 11 are provided. However, as shown in FIG.
In the chain type cutter 5c of the excavator 2 'according to the third embodiment, the endless chain 3 is further bent than the cutter 5b of the excavator 2 at the upper boundary between the overhang portion of the cutter and the cutter post. If the angle of the valley fold as viewed from the outer peripheral surface is further increased, the guide wheel 16 can be provided here. In this case, the guide wheel 10 is driven by a cylinder drive or the like.
, So that both wheels are horizontal. That is, the portion protruded by the guide wheel 10 at the time of excavation is above the upper surface of the guide wheel 16, thereby preventing the guide wheel 16 from directly contacting the soil layer at the time of excavation. FIGS. 17A and 17B show such a cutter 5c.
However, since the procedure is almost the same as that of the excavator 2, the description thereof is omitted. According to such a cutter 5c, there is no sliding portion from the cutter, and the durability of the device can be improved.
Other configurations are the same as those of the excavator 2, so that it is needless to say that the same operational effects as those of the excavator 1 can be obtained.

[0029]

As described above, according to the first aspect of the present invention, if the chain type cutter having a portion extending between the upper and lower ends in the horizontal movement direction is replaced, the grounding portion of the cutter is extended. It can excavate just below the middle obstacle. As a result, it is possible to excavate immediately below the underground obstacle without removing the underground obstacle and create an underground continuous wall.

According to the second aspect of the present invention, since there is provided a telescopic mechanism for extending a part between the upper and lower ends of the chain type cutter so as to be able to telescopically extend in the horizontal movement direction, If the size of the overhang portion of the cutter is freely changed, the overhang portion of the cutter can be used to excavate immediately below the underground obstacle. As a result, it is possible to excavate immediately below the underground obstacle without removing the underground obstacle and create an underground continuous wall. Further, in this case, it is not necessary to replace the heavy cutter or the overhanging portion, so that the working efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing an entire configuration of an excavation device for a trench for forming an underground continuous wall according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view taken along line II in FIG.

FIG. 3 is an explanatory view showing an example of a projecting shape of a chain type cutter of the device according to the first embodiment.

FIG. 4 is a detailed structural view of a chain type cutter.

FIG. 5 is an explanatory diagram showing an example of construction by the apparatus according to the first embodiment.

FIG. 6 is an explanatory diagram showing another example of construction by the device according to the first embodiment.

FIG. 7 is a partial detailed structural view of a chain-type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a second embodiment of the present invention is contracted.

FIG. 8 is a partial detailed structural view of a chain type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a second embodiment of the present invention is extended.

FIG. 9 is a partial detailed structural view of a chain-type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a first modification of the second embodiment of the present invention is contracted.

FIG. 10 is a partial detailed structural diagram of a chain-type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a first modification of the second embodiment of the present invention is extended.

FIG. 11 is a partial detailed structural diagram of a chain-type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a second modification of the second embodiment of the present invention is contracted.

FIG. 12 is a partial detailed structural view of a chain type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a second modification of the second embodiment of the present invention is extended.

FIG. 13 is a partial detailed structural view of a chain type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a third modification of the second embodiment of the present invention is contracted.

FIG. 14 is a partial detailed structural view of a chain-type cutter when a cylinder of an excavator for excavating an underground continuous wall forming groove according to a third modification of the second embodiment of the present invention is extended.

FIG. 15 is an explanatory diagram showing a construction example using the device according to the second embodiment of the present invention.

FIG. 16 is a front view showing an entire configuration of an excavator for a trench for forming an underground continuous wall according to Embodiment 3 of the present invention.

FIG. 17 is an explanatory diagram showing a construction example using the device according to the third embodiment of the present invention.

FIG. 18 is a front view showing the entire configuration of a conventional excavation device for a trench for forming an underground continuous wall.

FIG. 19 is an enlarged view taken along line XX in FIG. 18;

FIG. 20 is an explanatory view showing a construction example using a conventional apparatus.

[Explanation of symbols]

 1,2,2 'Excavator 2a Excavating blade 3 Endless chain 3a Link pin 4 Cutter post 4a Overhanging portion 5a1-5a4,5b, 5c Chain type cutter 6 Traveling trolley 7 Drive wheel 8,9,10,16 Guide wheel 11 Guide Rails 12, 13 cylinders (expansion and contraction mechanism)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Taichi Kusakari 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Shinsho Takasaka 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Keiki Ashida 1-8-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Kobe Steel, Ltd.Tokyo Head Office (72) Inventor Shigeru Katsukura 7-10-4, Nishigotanda, Shinagawa-ku, Tokyo No. Tomen Construction Machinery Co., Ltd.

Claims (7)

[Claims] 1. An endless chain having an excavating blade is attached to a traveling bogie with an endless chain stretched between upper and lower ends of a cutter post, and the chain cutter is rotated while being inserted into the ground. In an underground continuous wall formation groove excavation device for horizontally excavating a continuous wall formation groove in the ground, a chain type cutter in which an endless chain is stretched in a substantially straight line between upper and lower ends of a cutter post. One of a chain-type cutter having a portion extending between the upper and lower ends in the horizontal movement direction, and one of which is selectively replaceably attached to the traveling carriage, for forming an underground continuous wall. Ditch rig. 2. An endless chain having an excavating blade is attached to a traveling bogie having a cutter post spanned between upper and lower ends of a cutter post, and the chain cutter is rotated while being inserted into the ground. An excavation device for an underground continuous wall forming groove for excavating a continuous wall forming groove in the ground by horizontally moving, wherein a part between upper and lower ends of the chain type cutter is stretchably stretched in the horizontal moving direction. An excavation device for an underground continuous wall forming groove, comprising: a telescopic mechanism for extending the same. 3. The chain type cutter according to claim 1, wherein at least a part of a lower half is protruded from an upper half.
Or the excavation device for an underground continuous wall forming groove according to 2. 4. The excavation device for underground continuous wall forming grooves according to claim 3, wherein the chain-type cutter is extended in parallel from near a central portion between upper and lower ends to near a lower end. 5. The excavation device for an underground continuous wall forming groove according to claim 3, wherein the chain type cutter is formed so as to gradually protrude from the vicinity of the center between the upper and lower ends to the vicinity of the lower end. 6. The underground continuous wall forming groove excavating apparatus according to claim 3, wherein the chain type cutter is formed so as to gradually protrude from near the lower end between the upper and lower ends to near the center. 7. The excavation device for an underground continuous wall forming groove according to claim 3, wherein the chain type cutter is formed so as to gradually protrude from near the upper end to near the lower end between the upper and lower ends.