JPH08165899A - Tunnel lining method using timbering concurrently serving as reinforcing bar - Google Patents

Abstract

PURPOSE: To facilitate the execution of the waterproof/cutoff of a large-cross section tunnel and the reinforcing bar reinforcement of secondary lining. CONSTITUTION: Primary spraying of concrete is applied after the natural ground is excavated, large-diameter reinforcing bar arch timbering 11 is fixed on the inner face of the primary spray concrete 10, and secondary spraying of concrete is applied to about a half of the height of the large-diameter reinforcing bar arch timbering 11 to form primary lining concrete 17. A concrete waterproof reinforcing material 18 is sprayed or applied onto the inner face of the primary lining concrete 17, and secondary lining concrete is placed while the large- diameter reinforcing bar arch timbering 11 protruded on the inside of the primary lining concrete 17 is used as reinforcing bars.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lining method for excavating a tunnel having a large cross section by NATM (shot concrete method).

[0002]

2. Description of the Related Art In recent years, NATM has been used as a standard method for excavating a tunnel having a large cross section in rock. When constructing preventive water works, NATM has conventionally installed a secondary lining concrete after installing a waterproof sheet on the inner surface of the primary lining by spraying concrete on the tunnel peripheral wall and steel arch support. Was there.

However, in such a lining method, since the secondary lining concrete is placed after placing the waterproof sheet on the inner surface of the primary lining, it is complicated to reinforce the secondary lining with reinforcing bars. However, there was a problem that the efficiency was low and the construction cost was high.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve such a problem in tunnel lining, and
A tunnel lining method that allows easy construction of preventive water works when digging a tunnel with a large cross section by TM and reinforcement of secondary lining steel bars, improves the quality of tunnel lining, and reduces construction costs. The purpose is to provide.

[0005]

According to the present invention, in excavation of a tunnel having a large cross section, a primary shot of concrete is carried out after ground excavation, and a large diameter reinforced steel arch support is fixed to the inner surface of the primary shot concrete. , The primary lining concrete is formed by performing secondary spraying of concrete up to about half the height of the large diameter steel reinforced steel arch support, and the concrete waterproofing reinforcement is sprayed or applied on the inner surface of the primary lining concrete, The above-mentioned problem is solved by placing the secondary lining concrete by using the large-diameter reinforced steel arch supports remaining in a state of protruding inside the primary lining concrete as reinforcing bars.

[0006]

[Operation] Without installing a waterproof sheet on the inner surface of the primary lining, spray or apply concrete waterproof reinforcement material, and also use the large diameter steel reinforced steel arch support of the primary lining as the reinforcing bar of the secondary lining Since the secondary lining concrete is then placed, the work becomes easier and the quality of the tunnel lining is improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of an example of a method of excavating a large cross section tunnel. Here, the tunnel T to be dug is a large cross-section tunnel having a cross-sectional area of more than 200 m ² and a relatively flat cross-section, and two circular tunnels 1 are miniaturized in the upper half arch part 2 of this tunnel T. Pre-excavate with a tunnel machine.
Cable bolts 3 are driven from the circular tunnel 1 to the ground at a predetermined interval. Further, mortar is sprayed on the peripheral wall of the circular tunnel 1.

Then, the upper half arch portion 2 is shaped, cut, and excavated by a large hydraulic breaker of 4 tons or more. After excavation, prevention water works 5 and steel support works 6 are applied to the upper half arch portion 2. next,
The ground to be lowered in the lower half 7 and the invert 8 is drilled with a rock drill and loosened by loosening and blasting, and is dug down with a D11 class impact ripper, and water prevention 5 and steel support 6 are applied. , And then secondary lining with concrete.

FIG. 2 is a partial cross-sectional view showing a state before secondary lining in tunnel lining according to an embodiment of the present invention, and FIG. 3 is a partial vertical cross-sectional view showing a state after secondary lining, FIG. 4 is a cross-sectional view of a large diameter reinforced steel arch support. In this example,
In the excavation of the large cross section tunnel as described above, lining is performed as follows. First, after excavating the natural ground, primary spraying of concrete is performed, and the large diameter reinforced steel arch support 11 is fixed to the inner surface of the primary spraying concrete 10 with a lock bolt or the like.

The large-diameter reinforcing steel arch support 11 has a plurality of large-diameter reinforcing bars 12 curved in an arch shape along the outer circumference of the tunnel T and arranged in upper and lower two layers at intervals of about 15 cm. The large-diameter reinforcing bars 12 are connected to each other by the reinforcing bars 13, and a joint steel plate 14 is provided at one end. The necessary number of the large diameter reinforced steel arch supports 11 are connected according to the length of the outer circumference of the tunnel T. At this time, one end connects the joint steel plates 14 with the joint bolts 15, and the other end connects with the sleeve 16.

When the large diameter reinforced steel arch support 11 is fixed, the secondary blasting of concrete is performed up to about half the height H of the large diameter reinforced steel arch support 11 to form the primary lining concrete 17. . This primary lining concrete 17
Concrete waterproof reinforcement material 18 such as Zypex is sprayed or applied to the inner surface of the. At this time, as shown in FIG. 2, the large-diameter reinforced steel arch support 11 remains in a state of protruding inside the primary lining concrete 17.

Therefore, the large diameter reinforced steel arch support 1 which remains in a state of protruding inside the primary lining concrete 17
A secondary lining concrete 19 is placed by using 1 as a reinforcing bar. If necessary, it is also possible to strengthen the secondary lining by connecting additional reinforcing bars to the large-diameter reinforcing steel arch supporting structure 11 that remains in a protruding state. As described above, the waterproof sheet is not installed on the inner surface of the primary lining concrete 17, the concrete waterproofing reinforcement material 18 is sprayed or applied, and the large diameter reinforced steel arch support 11 at the time of the primary lining is secondaryly covered. Since the secondary lining concrete 19 is also placed as the reinforcing bar of the work, the work is facilitated and the quality of the tunnel lining is improved.

[0013]

As described above, according to the tunnel lining method of the present invention, it is easy to perform preventive water work when digging a tunnel having a large cross section with NATM and to reinforce the secondary lining. , The quality of tunnel lining can be improved and the construction cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example of a method of excavating a large cross section tunnel.

FIG. 2 is a partial cross-sectional view showing a state before the secondary lining of the tunnel lining according to the embodiment of the present invention.

FIG. 3 is a partial vertical sectional view showing a state after secondary lining.

FIG. 4 is a cross-sectional view of a large diameter reinforced steel arch support.

[Explanation of symbols] 1 circular guideway 2 upper half arch part 3 cable bolt 5 waterproof stop 6 steel support work 7 lower half part 8 invert part 10 primary shot concrete 11 thick steel bar arch support 12 thick steel bar 13 Connecting rebar 14 Joint steel plate 15 Joint bolt 16 Sleeve 17 Primary lining concrete 18 Concrete waterproofing reinforcement material 19 Secondary lining concrete T Tunnel

Claims (1)

[Claims] 1. In the excavation of a large-section tunnel, primary blasting of concrete is performed after ground excavation, and a large diameter reinforced steel arch support is fixed to the inner surface of the primary shot concrete to provide a large diameter reinforced steel arch support. To the half of the height of the primary lining concrete to form a primary lining concrete, spray or apply concrete waterproofing reinforcement to the inner surface of the primary lining concrete, the inside of the primary lining concrete A method of lining a tunnel using a reinforcement also serving as a reinforcement, characterized in that the secondary lining concrete is placed by using the large diameter reinforced steel arch support that remains in a protruding state as reinforcement.