JP3076207B2 - Top shaft advanced construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel construction method and, more particularly, to a top shaft construction method for advancing a shaft before construction of a main shaft.

[0002]

2. Description of the Related Art As a technique for constructing an overhead shaft, a mountain construction method using a sheet pile method or NATM (New Austrian tunneling method) and a construction method using a TBM (tunnel boring machine) for excavating a tunnel into a circular cross section are considered. Can be

[0003] As shown in Figs. 9 (a) and 9 (b), in the case of a top tunnel of the mountain method, the order shown by Arabic numerals in the figure, that is, the center of the top of the planned tunnel section as an advanced tunnel is excavated. Subsequently, both sides of the tunnel are excavated, and then a central portion, which is a main portion of the tunnel, and a lower center and both sides thereof are excavated to form a horseshoe-shaped cross section, followed by concrete lining such as spraying.

[0004] On the other hand, in the case of the TBM method, a pilot well excavation 61 as an advanced shaft is excavated and drilled near the top end of the planned tunnel section, and then a main well 60 having a circular section with a lower notch is excavated. doing.

[0005]

However, in the case of the above-mentioned mountain construction method, although the cross section of the main pit can be set relatively freely in consideration of the workability, the excavation speed and safety are higher than those of the TBM. There's a problem.

On the other hand, in the case of a circular advanced shaft, since the excavation shape is circular, a point that comes into contact with the main shaft excavation line having a circular or horseshoe-shaped cross section is a point, and the point is later from the top of the advanced shaft. There is a drawback that the improvement of the ground above the main pit, such as injection of a chemical solution for excavating the main pit and lock bolts, cannot be performed efficiently.

In the case where the upper support of the advanced shaft having a circular cross section is also used as the support of the main shaft, the excavation of the advanced shaft and the cross section and the cross section of the main shaft are required to secure the construction portion. Not only is it inefficient because of the excavation at the overlapped part, but when this is done, the final cross-sectional shape of the main pit becomes a strip like protrusion on the top of the design section. There is a drawback that the portion is formed and has an irregular shape, which is disadvantageous in terms of safety of the tunnel structure.

Accordingly, the present invention does not employ a mountain construction method such as blasting with emphasis on the speed and safety of excavation work.
A mechanical excavation method using an excavator such as a BM is premised, and the above-mentioned drawbacks in the TBM method are not eliminated. In other words, the ground near the top of the main pit is improved by constructing the upper part of the advanced shaft with the upper part of the main shaft, or the top of the advanced shaft is sprayed with H steel and concrete. By using the double-track tunnel, it is possible to construct an advanced tunnel construction method for horizontal tunnels with little extra excavation, even when laying double-track tunnels.

Another object of the present invention is to provide the above-described conventional T
The feature of BM's mechanical excavation is to provide a top shaft advanced construction method that can efficiently improve the ground at the top of the main pit while almost ensuring the excavation speed and safety.

[0010] Further, by using the upper support of the advanced shaft as a support for the main shaft to be excavated as it is later, the efficiency is improved and the construction period is shortened. Will not provide.

[0011]

SUMMARY OF THE INVENTION The present invention has been made based on the above objects, and the gist of the invention is as follows.
Before constructing the main shaft on the tunnel planned route, in the top shaft advanced construction method of excavating an advanced shaft near the inside of the top of the tunnel section of the main shaft, the upper part of the advanced shaft is referred to as the upper part of the main shaft. In the top shaft advanced construction method, the advanced shaft is excavated into an elliptical shape having a horizontally long cross-section so as to be inscribed in a linear manner.

In the drilling method for the above-mentioned advanced shaft and main shaft, if the machine is to be machined, TBM, NATM, a full shield TBM (a TBM having a shield machine) and the like are also used. Any method is required, but a method is required in which a circular cutter surface is inclined in the excavation direction to excavate the tunnel into a horizontally long elliptical cross section.

[0013] In addition, when the upper overlap portion of each of the advanced shaft and the main shaft is inscribed in a line, point contact occurs when the great circle inscribes the small circle. When an elliptical small circle is inscribed in a circle, the overlapping portion becomes linear, and this means a method of excavating the main pit with this linear overlapping portion.

According to another construction method of the present invention, if the upper part of the advanced shaft overlaps near the top of the main well, if this part is subjected to a pre-reinforcement work such as injection of a chemical solution or a lock bolt, the overlap with the conventional construction method may occur. It is easier to inject chemicals into the upper part of the excavation than in the pre-reinforcement work to be carried out, and to avoid the inconvenience of having to cut off the lock bolt portion that does not overlap when excavating the main pit, and construct it with a more appropriate construction method it can.

Further, another method of the present invention is to support a portion of a support or lining portion, such as H steel or a segment, which overlaps with a main shaft of an advanced shaft, and to support or cover a top end portion of the main shaft to be constructed later. It can also be used as part of the engineering department.

[0016]

According to the present invention, the upper part of the elliptical advanced shaft is excavated in order to excavate the horizontally long elliptical advanced shaft first, and then to excavate the upper part of the advanced shaft near the top end of the main shaft. It becomes wider, and appropriate pre-reinforcement work such as injecting a chemical solution for the main shaft and improving the ground of rock bolts is performed in this area.

Further, at least at the upper part of the upper shaft of the advanced shaft, near the top end of the main shaft, by spraying H steel and concrete in the main shaft, winding segments, or combining these materials to support or cover. It is convenient for construction.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the advanced shaft construction method of the present invention,
An outline of a TBM as an embodiment used in this advanced construction method will be described with reference to FIGS.

At the tip of the main beam 1, a cutter surface 2 inclined at an angle of, for example, 50 degrees with respect to a horizontal plane in the excavation direction is provided on the TBM.
The cutter drum 3 on which a number of cutters 14 are arranged is provided, and the electric motor 5 is rotated to excavate the ground. A thrust jack 9 is interposed between the main beam 1 having the cutter drum 3 and the gripper 8. When excavating, gripper 8
Is pressed against the pit wall by the gripper jack 13, and the thrust jack 9 is extended by using this as a reaction force to rotate the cutter drum 3 to excavate. A workbench 4 is arranged above the main beam 1. The angle formed between the rotation axis of the cutter surface 2 and the horizontal axis of the tunnel can be rotated at 50 degrees.

When the thrust jack 9 is excavated for one stroke, the rear support 7 is connected to the rear of the gripper 8 and is extended downward to ground, and then the gripper jack 13 is contracted and removed from the pit wall. After that, the gripper 8 is advanced by one stroke together with the rear support 7 by contracting the thrust jack 9, and the gripper 8 is pressed against the pit wall by extending the gripper jack 13 again, and the rear support 7 is contracted before the TBM. Resumes excavation. The roof support 10 presses against the upper part of the pit wall to prevent the TBM from rising due to excavation of the inclined cutter surface 2. The first-stage belt conveyor 11 transports the excavated waste by the cutter rearward, with its leading end located inside the center of the cutter drum 3 and its trailing end located behind the rear support 7. Drains to the back of the pit.

As shown in FIG. 1 (left half of the center line 31) described later, the rock drill 20 is a bedrock for fixing the main shaft lock bolt 30 radially at a predetermined interval to the top of the advanced shaft. This is a drill for drilling. Also,
The leading boring 15 drills the upper ground in front of the excavation of the TBM to form a boring hole 33, and then, as shown in FIG. 1 (right half of the center line 31), removes the ground from the boring hole 33. After the chemical liquid injection 32 for hardening is performed, the upper ground near the top end of the main shaft 35 is improved. Further, in the support erector 16, a ring-shaped H steel is wound around the inner periphery of the excavated pit wall 17, and then concrete is sprayed onto the pit wall 17 from above by a spray nozzle (not shown) to perform lining. Simultaneously with or separately from this concrete lining, Elekta 1
8, the segment 19 is wound around the pit wall 17, grout is injected between the segment and the ground through a grout hole at the center of the segment, and lining is performed (in FIG. 3, only the lower part of the pit wall is described. Can be omitted).

The method for advancing a pit shaft according to the present invention using the TBM having the above structure will be described below.

First, before constructing a main tunnel having a relatively large diameter as a two-lane or more lane or a double track along the planned tunnel line, the tunnel section of the main shaft 35 by a TBM from the starting base of the shaft, etc. Excavation of a horizontally elliptical advanced shaft is performed near the top of the inside of the tunnel so that the top of the tunnel overlaps linearly. In this excavation, the circular section of the TBM is inclined in front of the excavation direction so that the tunnel section becomes oblong in shape.

To excavate, the gripper 8 is pressed against the pit wall 17 to take a reaction force, the cutter surface 2 is pressed against the face by the pressure for extending the thrust jack 9, and the cutter drum 3 is rotated by the electric motor 5. While digging through the tunnel. When the thrust jack 9 is extended by one stroke, the excavation is interrupted, the rear support 7 is extended and grounded, and then the gripper 8 is contracted, and the extended thrust jack is contracted, so that the gripper 8 and the rear associated therewith are contracted. The support 7 is advanced, the gripper 8 is extended again, pressed against the pit wall 17, and then excavated by the cutter drum 3.

The excavated debris is scooped up by the cutter drum 3 and its tip is located in the first drum located inside the drum.
The conveyor 11 is dropped onto the step conveyor 11 and the second
It is discharged by the step belt conveyor 12.

The excavated tunnel is used as the support erector 1
6, the H steel is built in a ring shape along the circumference of the pit wall 17, and then concrete is sprayed on the pit wall including the H steel (FIG. 2). Depending on the properties of the tunnel ground, a segment 19 may be provided inside the segment transport hoist 18 instead of or simultaneously with the above-mentioned concrete spraying.
(Fig. 3).

Thereafter, when excavating the main pit, as shown in the left half of the center line 31 in FIG. 1, a lock bolt hole is formed in the circumferential direction of the tunnel using a rock drill 20, and a fixing material such as mortar is formed in the hole. Is inserted, the lock bolt 30 is inserted, and a nut (not shown) at the bolt head is tightened as a reaction force plate. In the figure, the improvement of the ground of three advanced tunnels with an oval cross section in the circumferential direction of the tunnel was
It will also serve as a ground improvement above the top of No. 5. In this case, a new lock bolt 36 can be driven into the side wall of the main shaft 35 even when the main shaft is excavated.

As a pre-reinforcement work for the ground, separate from the lock bolts, a boring hole 33 is formed in the upper part ahead of the advanced shaft as shown in the right half of the center line 31 in FIG. It is also possible to perform excavation 32 by reinforcing and hardening a soft ground.

In the advanced shaft obtained as described above, the main shaft including the entire cross section of the advanced shaft is excavated by superimposing the top portion of the advanced shaft in a line rather than a dot. In addition, the support near the top of the above-described advanced shaft can be used as a part or all of the support near the top end of the main shaft.

In addition, the pre-reinforcement work such as the injection of a lock bolt and a chemical solution during the construction of the advanced shaft is performed as it is or partially in the excavation of the main shaft.

[0031]

As described above, according to the present invention, since the upper portion of the advanced shaft is overlapped with the upper portion of the main shaft in a line in the circumferential direction of the tunnel, the following effects can be expected.

[0032] The length of contact between the excavation line of the advanced shaft and the main shaft excavation line can be long, and pre-reinforcement work from the advanced shaft and construction of lock bolts for the main shaft can be performed over a wide range. The stability and excavation efficiency of the mountain can be improved.

When the support of the advanced shaft is also used as the support of the main shaft, the construction period can be shortened, and it becomes economical.

In the advanced shaft of the present invention having an elliptical cross section,
Since the width of the bottom plate can be made wider than that of a circular TBM of the same size, a large bogie can be used as shown in FIGS.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one feature of the method of the present invention.

FIG. 2 is a schematic sectional view showing another feature of the method of the present invention.

FIG. 3 is a vertical cross-sectional view of a digging device used in the method of the present invention as viewed from the lateral direction.

FIG. 4 is a front view of the cutter surface of FIG. 3;

FIG. 5 is a sectional view taken along line AA of FIG. 3;

FIG. 6 is a sectional view taken along line BB of FIG. 3;

FIG. 7 is a schematic vertical sectional view showing a state where dump trucks pass each other in a top tunnel that is the method of the present invention.

FIG. 8 is an explanatory diagram in which a dump truck can be turned in a top shaft.

FIGS. 9 (a) and 9 (b) are explanatory diagrams showing a conventional excavation order in a mountain tunnel due to blasting or the like.

FIG. 10 is a vertical cross-sectional view of a conventional TBM in a top shaft having a circular cross section.

──────────────────────────────────────────────────続 き Continuing on the front page (73) Patent holder 000201478 Maeda Construction Industry Co., Ltd. 2-10-26 Fujimi, Chiyoda-ku, Tokyo (72) Inventor Takashi Sakai 2-10-2 Otowa, Bunkyo-ku, Tokyo Otowa NS Building 7F Inside the Advanced Construction Technology Center (72) Inventor Mitsuhiro Higo 2-5-8 Kitaaoyama, Minato-ku, Tokyo Inside Mazumi Co., Ltd. (72) Inventor Yoshiaki Ishida 4-12-20 Nihonbashi Honcho, Chuo-ku, Tokyo Inside Sato Kogyo Co., Ltd. (72) Masaru Nakamura 3-1-1 Ueno, Hirakata City, Osaka Prefecture Inside Osaka Plant of Komatsu Manufacturing Co., Ltd. (72) Takeshi Suzuki 2-10-26 Fujimi, Chiyoda-ku, Tokyo Maeda Construction Industry (56) References JP-A-6-137062 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 9/00 E21D 20/00 E21D 11/12 E21D 13 / 00-13/04

Claims (4)

(57) [Claims] 1. A method of excavating an advanced shaft near the inside of a top section of a tunnel section of the main shaft before constructing the main shaft on the planned tunnel line. A top shaft advanced construction method, characterized in that the advanced shaft is excavated into an elliptical shape having a laterally long cross section so that the shaft is substantially inscribed in a line with the upper part of the main shaft and overlaps the main shaft. 2. The excavation of a top shaft according to claim 1, wherein when excavating the advanced shaft, a pre-reinforcement work such as injection of a chemical solution or ground improvement using a lock bolt is performed on the upper ground of the shaft. Construction method. 3. The top pit shaft according to claim 1, wherein, when excavating the advanced shaft, an upper support of the shaft also serves as a top end support of a main shaft to be excavated later. Construction method. 4. The pit shaft according to claim 1, wherein, when excavating the advanced shaft, an upper lining of the shaft is also used as a top lining of a main shaft to be excavated later. Advanced construction method.