JPH07331985A - Preceding lock bolt construction and boring method of large section tunnel by means of release blasting - Google Patents

Abstract

PURPOSE:To lower the cost of production by making improvements in safety and productivity, in the natural ground of a medium hard rock. CONSTITUTION:A pilot tunnel B is constructed in the lower half part of a boring scheduled section A, while a lock bolting hole is bored in the inmost recess of the section A from the tunnel B, inserting each lock bolt 4 into the hole, and it is bonded by a fixer material, and peripheral natural ground is joined together by these lock bolts 4. Utilizing the rest holes, the natural ground is released to some extent by means of blasting and an upper half part A1 is bored and, after earth is discharged and concrete 13 is sprayed around, the lower half part is bored and earth is discharged as well, and thus those of boring, earth-moving and concrete spraying are parallelly carried out at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of excavating a large-section tunnel by constructing a preceding rock bolt and loosening and blasting.

[0002]

2. Description of the Related Art When excavating a tunnel, the face of the face is excavated by blasting, breaking, shoveling, etc., depending on the geology of the face of the face by 1-2 m. It prevents loosening of the ground and collapse of the face. After that, shotcrete is applied to prevent the crown and the skin from falling off.

[0003]

As described above, according to the prior art, it is necessary to carry out the above-mentioned work within 1 to 2 m before the face, so that the risk is high, the productivity is low, and the cost cannot be reduced.

It is an object of the present invention to provide a method for excavating a large-section tunnel by constructing a preceding rock bolt and loosening and blasting to improve the safety and productivity and reduce the cost in the medium-hard rock ground. .

[0005]

The excavation method according to the present invention comprises a pilot tunnel construction step of constructing a pilot tunnel in the lower half of the planned excavation section, and a predetermined ratio of the excavation width from the pilot tunnel to the interior of the planned excavation section. Rock bolt hole drilling process to drill the lock bolt hole to the depth of the lock bolt, fixing material insertion process to insert the fixing material into the hole end of the lock bolt hole, and lock bolt and lock bolt insertion to the lock bolt hole Lock rod and relay rod insertion step for inserting the relay rod for rotation with the threaded portion while rotating, and the fixing material at the hole end is mixed and agitated by pushing while pushing the lock bolt while rotating the lock bolt and the ground bolt. Fixing material mixing and agitation process that adheres all the mountains together,
The relay rod for inserting the lock bolt is reversely rotated to separate the relay rod for inserting the lock bolt from the lock bolt, and the relay rod for inserting the lock bolt is pulled back into the pilot tunnel and the screw is removed. By repeating the process of collecting the relay rod for inserting the lock bolt and the hole drilling process for the lock bolt to the process of collecting the relay rod for inserting the lock bolt, the surrounding ground outside the planned excavation section is sewn with multiple lock bolts. The sewn process using the lock bolt, the loosening and blasting process to facilitate the excavation by using the holes left in the sewing process, the excavation facility installation process to install the excavation facility in the pilot tunnel, and the excavation The upper half of the planned section is excavated, and the excavated soil is excavated by the earth removing equipment. A cleat spraying step, and characterized by comprising a lower half of the excavation process of earth removal of soil excavated by drilling a lower half of the large cross-section tunnels.

[0006]

In the excavating method of the present invention, the peripheral ground on the outer side of the planned excavation section is sewn with a plurality of lock bolts. Then, loosen and blast, excavate the upper half of the planned excavation section, discharge the excavated soil and spray the concrete, then excavate the lower half and discharge the soil, excavate the soil and spray the concrete. Work in parallel at the same time.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

(1) Pilot tunnel construction step (FIG. 1) A pilot tunnel B is constructed in the lower half of the excavated section A of the large section tunnel by a tunnel boring machine (not shown). The inner diameter D of the tunnel B is, for example, about 3 m with respect to the width W (for example, 12 m) of the excavation planned cross section A having the height H (for example, 7.4 m).

(2) Rock bolt hole drilling process (FIG. 2) From inside the pilot tunnel B to the depth of the planned excavation section A by the hole drilling machine 1, for example, a depth h of 1/5 to 1/3 of the width W Drill the hole 2 for the lock bolt.

(3) Fixing material insertion step (FIG. 3) At the bottom of the hole 2 for the lock bolt, a fixing material (for example, a cement mortar type or resin type capsule that also uses a quick-setting material) 3
Insert.

(4) Inserting the lock bolt and the relay rod for inserting the lock bolt (FIG. 4) In the lock bolt hole 2, the lock bolt 4 and a plurality of lock bolts (finally three as shown in FIG. 5) are inserted. The relay rods 5 for insertion are reciprocally connected to each other by a threaded portion, and are inserted while rotating with the hole drilling machine 1. The surface of the rod 5 is coated to prevent the fixing material 3 from adhering thereto.

(5) Fixing Material Mixing and Stirring Step (FIG. 5) The fixing material 3 is mixed and stirred by pushing the lock bolt 4 while rotating it, and the lock bolt 4 and the ground are bonded together.

(6) Step of separating relay rod for inserting lock bolt (FIG. 6) The relay rod 5 for inserting lock bolt is reversely rotated and separated from the lock bolt 4. At this time, the screw diameter of the lock bolt and the relay rod for inserting the lock bolt is smaller than the other screw diameters, and the loosening torque is made smaller.
When the relay rod for inserting the lock bolt is rotated in the reverse direction with the drilling machine, first, the screw portion between the lock bolt and the relay rod for inserting the lock bolt is separated first.

(7) Collection Step of Relay Rod for Inserting Lock Bolt (FIG. 7) The relay rod 5 for insertion of the lock bolt is sequentially pulled back into the pilot tunnel B, and the screw portion is removed to collect.

(8) Sewing process using lock bolts (FIG. 8) (2) Drilling process for rock bolts to (7) Collecting process of relay rods for inserting lock bolts are repeated until the periphery of the planned excavation section A The ground C is sewn with a plurality of lock bolts 4.

(9) Loose blasting process (FIG. 9) (8) Install dynamite 6, electric detonator 7, insert 8, busbar 9 in the loosing and blasting hole D created in the sewing process with the lock bolt, and loosen and blast I do. Although only one hole is shown in FIG. 9 for the sake of explanation, the amount of dynamite 6 to be charged and the number of holes D are determined according to the geology of the natural ground.

(10) Excavation equipment installation process (Fig. 10) In the pilot tunnel B, an excavation equipment for excavating soil,
For example, the belt conveyor 10 is installed.

(11) Upper half excavation process (FIG. 11) The upper half A1 of the planned excavation section A is excavated by the large excavator 11 and excavated soil is discharged outside the tunnel by the belt conveyor 10, for example.

(12) Concrete spraying process (see FIG. 1)
2) The concrete spraying machine 12 sprays concrete 13 for preventing weathering of the excavated surface and for the collapse of the top and the skin from falling onto the inner peripheral wall of the upper half A1.

(13) Lower Half Excavation Step (FIG. 13) After excavating the lower half A2 of the planned excavation section A with the large excavator 11, the equipment in the pilot tunnel B such as the belt conveyor 10 is removed.

[0021]

As described above, according to the present invention, excavation can be facilitated by loosening and blasting even medium-sized rocks, and subsequent excavation, earth removal and concrete spraying can be performed simultaneously in parallel. I can. Therefore, it is possible to improve safety and productivity and reduce costs.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating a pilot tunnel construction step.

FIG. 2 is a cross-sectional view illustrating a rock bolt hole drilling process.

FIG. 3 is a sectional view illustrating a fixing material insertion step.

FIG. 4 is a cross-sectional view illustrating a lock bolt and a relay rod insertion step for inserting the lock bolt.

FIG. 5 is a sectional view illustrating a fixing material mixing and stirring step.

FIG. 6 is a cross-sectional view illustrating a relay rod separating step for inserting a lock bolt.

FIG. 7 is a cross-sectional view illustrating a relay rod insertion step for inserting a lock bolt.

FIG. 8 is a cross-sectional view illustrating a sewing process using lock bolts.

FIG. 9 is a sectional view illustrating a loosening and blasting step.

FIG. 10 is a cross-sectional view illustrating an earth removal facility installation process.

FIG. 11 is a sectional view illustrating an upper half excavation process.

FIG. 12 is a sectional view illustrating a concrete spraying step.

FIG. 13 is a cross-sectional view illustrating a lower half excavation process.

[Explanation of symbols]

 A ... Planned excavation section A1 ... Upper half A2 ... Lower half B ... Pilot tunnel C ... Surrounding ground D ... Loose blast hole 1 ... Drilling machine 2・ ・ ・ Lock bolt hole 3 ・ ・ ・ Fixing material 4 ・ ・ ・ Lock bolt 5 ・ ・ ・ ・ Lock bolt insertion relay rod 6 ・ ・ ・ Dynamite 7 ・ ・ ・ Electric detonator 8 ・ ・ ・ Insert 9・ Bus 10 ・ ・ ・ Exhaust equipment such as belt conveyor 11 ・ ・ ・ Large excavator 12 ・ ・ ・ Concrete spraying machine 13 ・ ・ ・ Shot concrete

Claims (1)

[Claims] 1. A pilot tunnel construction step of constructing a pilot tunnel in the lower half of a planned excavation section, and drilling a rock bolt hole from the pilot tunnel to the depth of the planned excavation section to a depth of a predetermined proportion of the excavation width. Lock bolt hole drilling process, fixing material inserting process to insert fixing material into the hole end of the lock bolt hole, and lock bolt and lock bolt inserting relay rod are added to the screw hole with the screw part while rotating. A lock bolt to be inserted and a relay rod insertion step for inserting the lock bolt, and a fixing material mixing and stirring step of mixing and agitating the fixing material at the hole end by pushing the lock bolt while applying rotation to adhere the entire area between the rock bolt and the ground. , Reversely rotate the relay rod for inserting the lock bolt to separate the relay rod for inserting the lock bolt from the lock bolt. Inserting relay rod, separating the lock bolt inserting relay rod into the pilot tunnel, removing the screw, and collecting the relay rod for inserting the lock bolt, and inserting the lock bolt from the hole for drilling the lock bolt. The relay rod recovery process is repeated to sew the surrounding ground outside the planned excavation cross section with multiple lock bolts, and the drilling process is facilitated using the lock bolt sewing process and the holes remaining in the sewing process. Loosening and blasting process, earth unloading equipment installation process to install earth unloading equipment in the pilot tunnel, excavation of the upper half of the planned excavation section, and excavation soil is excavated by the earth unloading equipment. And a concrete spraying process of spraying concrete onto the upper half excavation surface,
A method for excavating a large-section tunnel by constructing a preceding rock bolt and loosening and blasting, the method comprising: excavating a lower half of the large-section tunnel to remove excavated soil.