JP3076927B2 - First-strength reinforcement structure and construction method for underground space - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-strengthening structure for reinforcing surrounding ground prior to excavation of an underground space and a method of constructing the underground space.

[0002]

2. Description of the Related Art Conventionally, in a construction method of an underground space, for example, a construction method of a mountain tunnel, when the excavation surface is expected to collapse or deform immediately after excavation such as a cracked ground, an unconsolidated ground, etc. Reinforce the ground in front of the face before excavating the main body. As a method of reinforcing such ground, for example, there are a horizontal jet grout method, a pre-lining method, a downward bolt method, and the like. Here, in the horizontal jet grouting method, a large number of columnar improved bodies are arranged in an arch shape along the outer periphery of the tunnel at an elevation angle of about 5 ° to 20 ° on the ground in front of the face, and the tunnel is used as a bearing for the tunnel. In the prelining method, a groove is cut along the outer periphery of the tunnel in front of the face, and immediately after the cutting, the groove is filled with a curable material to form an arch-like shell to be used as a preload for the tunnel. In addition, the downward bolt construction method from the ground surface uses rock bolts that are installed almost vertically in front of the tunnel face from the surface before tunnel excavation to integrate the ground surface and the ground in front of the tunnel to reduce the looseness of the surrounding ground. It is to prevent.

[0003]

However, in the conventional method of reinforcing the ground in front of the face, the conventional improved method of the horizontal jet grout method has an elevation angle of about 5 to 20 ° because the cylindrical improvement body has an elevation angle of about 5 to 20 °. Since the ground inside the improved body fell down and there was more digging, it was difficult to construct the improved body in the lower half of the tunnel and in the invert due to mechanical restrictions. There is a problem that the leg of the body sinks and the top of the tunnel or the ground surface may be displaced. In addition, in the prelining method, a large-sized machine corresponding to the shape of the tunnel cross section is required, so that the machine cost is high, and it is difficult to follow the change in the shape of the tunnel cross section. There is a problem that other work such as excavation cannot be performed in parallel. Further, this prelining method has a problem that it is difficult to receive a long preload due to mechanical restrictions, and that the range of prelining is limited to the upper half arch as in the case of the horizontal jet grouting method. In addition, the downward bolt method from the ground surface cannot be carried out when the tunnel cover is large or the land surface cannot be occupied, etc. There is a problem that can not be.

Accordingly, the present invention has been made in view of the above problems, and can be carried out by a small-sized machine. It is an object of the present invention to provide a first-strength reinforcement structure of a surrounding ground and a method of constructing an underground space capable of easily reinforcing a ground in front of a face without being restricted by a cross-sectional shape of the space.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and a gist of the invention is to arrange a plurality of ground rocks in the front ground in order to reinforce the ground rock before excavating the face. A pre-strengthened reinforcement structure comprising a linear structure, wherein each of the linear structures starts drilling toward the face face and extends a predetermined length in the direction of excavation, and then extends outside the planned underground space. A perforation that bends in the direction and extends a predetermined length further across the designed excavation section of the underground space, and the axial tension of the curable material such as cement mortar, cement milk, foamed resin, and the linear structure filled in the perforation There is provided a pre-strengthened structure constituted by a linear reinforcing material such as a glass fiber or a PC cable disposed in the curable material so as to bear a force.

Here, various types of drilling machines capable of curving can be used to form the holes, but a small machine such as a normal boring drilling machine is preferably used. To install a linear structure using such a drilling machine,
For example, first, a drilling machine is set at an arbitrary position facing the face. Then, drilling is started in the direction of excavation, and after extending a predetermined length, the drilling direction is turned to the outside of the planned underground space, and further drilled a predetermined length across the designed excavation section of the underground space. . Next, after removing the drilling device at the tip of the drilling machine from the drilling tube of the drilling machine, a linear reinforcing material is inserted into the drilling tube. Further, a curable material is driven into the perforations while the excavated pipe is pulled out to obtain the linear structure.

Another aspect of the present invention resides in that a plurality of traversing a predetermined excavation cross section of a planned underground space are formed by extending a predetermined length in the excavation direction from the face and then bending the same in the ground in front of the face. A step of providing a linear structure, and a step of excavating the face face and removing the linear structure located inside the underground space, and the periphery of the underground space during and after excavation by the linear structure There is a construction method of the underground space to reinforce the ground.

[0008]

According to the pre-strengthening reinforcement structure of the present invention, each linear structure is
After extending in the direction of excavation from a drilling machine installed at an arbitrary location on the face, it is bent in an arbitrary direction and driven into an arbitrary location in the surrounding ground of the underground space. Makes it possible to reinforce mountains. In addition, the ground around the underground space is supported substantially perpendicularly to the designed excavation section of the underground space, so that the outer ground is strongly reinforced, and the flaking of the designed excavation section after excavation is reduced.

In the method of constructing an underground space according to the present invention, in the step of providing the linear structure, the shape of the face and the change in the shape can be easily coped with by arbitrarily selecting the place of construction with respect to the face. To reinforce the surrounding mountains, and to allow parallel work with excavation of the underground space.

[0010]

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In this embodiment, as shown in FIG. 1, a first-strength reinforcing structure 12 is provided to reinforce a ground 11 around a flat large-section tunnel 10 having a height of about 15 m and a width of about 20 m as an underground space.
Is driven into the ground 11 in front of the face 13. The first-strength reinforcement structure 12 is constituted by a plurality of linear structures 14, and each linear structure 14 is bent at a radius of about 9 m after extending in the tunnel excavation direction for a predetermined length from the face face,
A predetermined length is buried in the ground 11 around the tunnel across the planned tunnel design excavation section 15. As shown in FIG. 2, the linear structures 14 are arranged radially outward of the tunnel to reinforce the ground 11 around the tunnel during or after the excavation of the tunnel 10 from the entire periphery. . The length and number of the linear structures 14 to be buried in the ground around the tunnel are design items calculated from geological conditions, design support strength after completion of tunnel excavation, and the like. The length of 14 in the tunnel excavation direction is arbitrarily set in consideration of the workability of the excavation work, the capability of the drilling machine, and the like. In addition, the linear structure 14 is
As shown in an enlarged manner in FIG. 3, a perforation 16, a cement mortar 17 filled in the perforation 16, and the entire periphery thereof is adhered to the ground around the perforation 16, and is disposed substantially at the center of the cement mortar 17. , And a glass fiber 18 that bears a tensile force applied to the linear structure 14.

In the linear structure 14, a drilling machine 19 is installed at an arbitrary position on the face of the face, that is, on a bench in the upper half of the tunnel in the present embodiment. And drilling a predetermined length of drilling 16, then removing the drilling equipment at the tip of the drilling machine 19, inserting the glass fiber 18 to the tip of the drilling 16, and pulling out the drilling pipe while inserting the cement mortar 17 in the drilling hole. Into the ground by press-fitting.

When the surrounding ground is reinforced by driving the linear structure 14, the tunnel 10 is excavated. The excavation of the tunnel 10 can use various excavation methods commonly used in the mountain tunnel construction method. At the same time, a part 14 'of the linear structure 14 located in the tunnel is also removed. In addition, at the time of excavation, a part 14 'of the linear structure 14 located in the tunnel prevents the face from being pushed into the inner side of the face as a so-called mirror lock bolt. After the excavation, the linear structure 14 is, as shown in part A of FIG.
Only the linear structure 14 ″ extending outside the tunnel design excavation section 15 is left in the ground, and the linear structure 14 ″ is located substantially perpendicular to the tunnel design excavation section 15,
The ground around the tunnel 10 is supported by the same operation as the lock bolt of the conventional front bonding method. In addition, since the linear structure 14 is driven substantially perpendicularly to the tunnel design excavation section 15, the digging in tunnel excavation is reduced. In addition, by appropriately moving the drilling machine 19 to a place where it does not hinder the excavation operation, the excavation operation and the installation operation of the linear structure 14 ″ can be performed in parallel.

FIGS. 4 (a) to 4 (d) show an example of a drilling method for drilling a hole 14 to be bent by the drilling machine 19 of the present embodiment, and a so-called whip stock method (JIS M010).
2). That is, in this method, the tip excavator 20 is configured such that a conical steel guide 21 having a predetermined length is used.
And an auxiliary cutting bit 22 that expands and contracts along one inclined side of the conical steel guide 21. After the conical steel guide 21 is fixed to the downhole (see (a)), the auxiliary cutting The bit 22 is extended along the inclined surface to drill a hole at a predetermined angle in a direction different from the drilling direction (see (b)). When the drilling of the predetermined length by the auxiliary cutting bit 22 is completed, it is contracted (see C), the tip excavator 20 is pulled out, the diameter is increased by the excavating bit 23 (see d), and then the drilling of the predetermined length is performed. Then, the perforation 14 is bent by repeating such a process.

In the present embodiment, the case where the present invention is employed when constructing a flat large-section tunnel is described. However, the present invention can be employed in constructing any other underground space having a face.

[0016]

As described above, the linear structure constituting the pre-strengthening reinforcement structure of the present invention can be constructed at an arbitrary position on the face by a small machine such as an ordinary boring drill. Since the linear structure can be bent in any direction around the underground space, it can be solidly supported by supporting the surrounding ground from the entire circumference of the underground space according to changes in the shape and cross section of the underground space. A stable reinforcing structure can be provided at low cost.

In the method of constructing an underground space according to the present invention, a linear structure that bends in an arbitrary direction is constructed toward a face face, so that the surrounding ground during and after excavation can be easily formed from any direction. Underground space can be constructed safely and promptly, and the construction position of the linear structure can be arbitrarily selected to perform ground reinforcement and underground space excavation in parallel. This allows for more efficient construction of an underground space.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of a pre-strengthening reinforcement structure in the present embodiment.

FIG. 2 is a sectional view taken along line BB in FIG.

FIG. 3 is an enlarged sectional view taken along line CC of FIG.

FIGS. 4A to 4D are explanatory views showing an example of a method of forming a hole to be bent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tunnel (underground space) 11 Ground mountain 12 First-strength reinforcement structure 13 Face face 14 Linear structure 15 Tunnel design excavation section 16 Perforation 17 Cement mortar (hardening material) 18 Glass fiber (Linear reinforcement)

Claims (2)

(57) [Claims] 1. A pre-strengthening reinforcement structure of a surrounding ground formed of a plurality of linear structures disposed in a front ground before excavation of a face, wherein the linear structure is moved in a direction of excavation from a face. A perforation that traverses the designed excavation cross section of the underground space that is to be bent after being extended for a predetermined length, and a hardening material filled in the perforation and a linear reinforcing material that bears an axial tensile force of the linear structure. A first-strength reinforcement structure characterized by being constituted by: 2. A step of providing a plurality of linear structures in the ground in front of the facet, extending a predetermined length from the facet in the direction of excavation and then bending to cross the designed excavation section of the planned underground space. Excavating the face and removing the linear structure located inside the underground space, and reinforcing the ground around the underground space during and after excavation by the linear structure. Construction method.