CN214464254U

CN214464254U - Stable supporting structure for tunnel exit of loose and collapsed body covering layer tunnel

Info

Publication number: CN214464254U
Application number: CN202120645655.XU
Authority: CN
Inventors: 赵云鹏; 张国磊; 杨宁伟; 陶国胜; 尹金山; 肖凎; 孙伟杰
Original assignee: CCCC First Highway Xiamen Engineering Co Ltd
Current assignee: CCCC First Highway Xiamen Engineering Co Ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2021-10-22
Anticipated expiration: 2031-03-30

Abstract

The utility model discloses a loose slumped body covering layer tunnel exit stable supporting structure, which comprises a reinforced sleeve arch arranged at the tunnel portal and a double-row grouting small conduit advanced support arranged along the tunnel design contour line; the reinforced arch sheathing comprises an arch sheathing foundation and an arch sheathing pipe shed, the arch sheathing foundation comprises cement piers and vertical grouting steel pipes, the two cement piers are respectively supported under the left end and the right end of the arch sheathing pipe shed, the lower parts of the vertical grouting steel pipes are inserted into the mountain bedrock, and the upper parts of the vertical grouting steel pipes extend into the corresponding cement piers; the advanced support of the double-row grouting small guide pipes comprises double-row advanced small guide pipes driven into the tunnel face, the drilling angle of the first row of advanced small guide pipes is 30-35 degrees, and the drilling angle of the second row of advanced small guide pipes is 10-15 degrees. The entrance to a cave is strutted through the integrated configuration of reinforcement type cover arch and double slip casting pipe advance support, effectively prevents to appear slumping in tunnel construction in-process exit position department.

Description

Stable supporting structure for tunnel exit of loose and collapsed body covering layer tunnel

Technical Field

The utility model belongs to the technical field of the engineering construction, concretely relates to stable supporting construction in a hole suitable for loose body overburden tunnel work progress that slumps.

Background

In local plateau areas (such as Guizhou province) of China, landslide geological disasters are prone to frequent occurrence due to special geological and meteorological conditions, and the safety of highway construction is seriously affected.

The tunnel portal of a certain construction tunnel has steep terrain, the side-up slope is a forward slope, and the tunnel portal consists of strongly weathered sandy slate and clay containing broken stone and powder, the joint crack develops, and is of a cracked loose structure and poor in stability. At present, side and up slope protection is usually adopted for tunnel exit construction of the landslide body tunnel firstly, and then tunnel exit construction is carried out. If loose landslide protection is firstly carried out and then tunnel exit construction is carried out, the whole project construction period is delayed by 10 months, and the construction cost is increased by about 400 ten thousand yuan.

SUMMERY OF THE UTILITY MODEL

To the above problem, the utility model aims at providing a stable supporting construction in the hole that goes out in loose body overburden tunnel work progress that collapses can not only guarantee construction safety quality, can practice thrift construction cycle and engineering cost greatly moreover.

Therefore, the utility model discloses the technical scheme who adopts does: a loose slumped body covering layer tunnel exit stable supporting structure comprises a reinforced sleeve arch arranged at a tunnel portal and a double-row grouting small conduit advanced support arranged along a tunnel design contour line; the reinforced type arch sleeving comprises an arch sleeving foundation and an arch sleeving pipe shed, the arch sleeving foundation comprises cement piers and vertical grouting steel pipes, the two cement piers are respectively supported under the left end and the right end of the arch sleeving pipe shed, each cement pier is provided with a plurality of vertical grouting steel pipes for reinforcement, the lower part of each vertical grouting steel pipe is inserted into the mountain bedrock, and the upper part of each vertical grouting steel pipe extends into the corresponding cement pier; the double-row grouting small conduit advance support comprises double-row advanced small conduits driven into a tunnel face, the drilling angle of the first row of advanced small conduits is 30-35 degrees, the drilling angle of the second row of advanced small conduits is 10-15 degrees, one ends of the advanced small conduits are supported on an un-excavated rock body, the other ends of the advanced small conduits are fixed on a steel arch frame, a beam type structure with a fulcrum at the front end is formed, and each advanced small conduit is a grouting steel pipe.

Preferably, the length, width and height of the cement pier are 4m × 6m × 1m, the lower part of each vertical grouting steel pipe is inserted into the mountain bedrock by 1m, the upper part of each vertical grouting steel pipe extends into the corresponding cement pier by 0.5m, the distance between every two vertical grouting steel pipes is 1m, and 15 vertical grouting steel pipes are arranged in a quincunx manner in total in 3 rows and 5 vertical rows. The arrangement mode and the size parameters of the vertical grouting steel pipes are optimized, and the foundation strength is further improved.

Preferably, each advanced small conduit is reserved with 10cm and firmly welded on the steel arch frame, and the hole forming positions of the double rows of advanced small conduits are staggered with each other along the extending direction of the tunnel, so that the surrounding rock is fully supported, and the supporting strength is further increased.

More preferably, the circumferential distance of each row of the small advancing guide pipes is 40cm, the longitudinal distance of each row of the small advancing guide pipes is 240cm, and each four steel arches form one construction cycle.

Preferably, the front end of each small advanced conduit is processed into a taper shape, a stiffening hoop is welded at the tail part, and phi 6mm grouting holes are drilled in a quincunx shape at intervals of 15cm on the periphery of the conduit wall.

The utility model has the advantages that: through set up the enhancement type cover in tunnel entrance department and encircle, set up double slip casting pipe advance support along the tunnel design outline line, increase the tunnel and go out the supporting intensity of the loose slide collapse body overburden in position department, strengthen the self-supporting ability of loose country rock, effective control country rock deformation effectively prevents in the tunnel work progress and goes out the position department and appear slumping, can not only guarantee construction safety quality, can practice thrift construction cycle and engineering cost greatly moreover. By applying the construction method, the construction period is obviously shortened, the construction period can be advanced by 10 months, and the construction cost is reduced by about 400 ten thousand yuan; no need of adding special equipment, strong process operability, economy and reasonability, and easy popularization.

Drawings

Fig. 1 is a schematic structural view of a reinforced socket arch.

Fig. 2 is an elevation view of a double-row grouting small conduit advance support.

Fig. 3 is a longitudinal section view of a double-row grouting small conduit advance support.

Detailed Description

The present invention will be further explained by the following examples in conjunction with the accompanying drawings.

A tunnel exit stable supporting structure of a loose collapse body covering layer comprises a reinforced sleeve arch arranged at a tunnel entrance shown in figure 1 and double-row grouting small guide pipe advanced support arranged along a tunnel design contour line shown in figures 2 and 3.

As shown in fig. 1, in order to ensure the safety of tunnel construction, a reinforced type cover arch is designed. The reinforced arch mainly comprises an arch foundation 1 and an arch pipe shed 2. The arch-sleeving pipe shed 2 is of an existing arch-sleeving pipe shed structure, and the arch-sleeving foundation 1 is an added part so as to increase the foundation strength of the arch-sleeving pipe shed. The set arch foundation 1 mainly comprises two cement piers 1a and a plurality of vertical grouting steel pipes 1 b. Two cement piers 1a support respectively under the both ends about cover arched pipe canopy 2, and every cement pier 1a is equipped with a plurality of vertical slip casting steel pipes 1b and consolidates, and in the lower part of vertical slip casting steel pipe 1b inserted mountain body basement rock, the upper portion stretched into corresponding cement pier 1 a.

Preferably, the length, width and height of the cement pier 1a are 4m × 6m × 1m, the lower part of the vertical grouting steel pipe 1b is inserted into the mountain bedrock by 1m, the upper part of the vertical grouting steel pipe extends into the corresponding cement pier 1a by 0.5m, and the total length of the vertical grouting steel pipe 1b is 1.5 m. The vertical grouting steel pipes 1b are arranged in a quincunx shape, the distance is 1m, 3 rows are arranged horizontally, 5 rows are arranged longitudinally, and 15 grouting steel pipes are arranged in total. The grouting pressure is controlled to be 0.5-1 MPa, 1:1 cement slurry is adopted as the slurry, and C30 concrete is poured as the cement pier 1 a.

Referring to fig. 2 and 3, the tunnel is constructed at a position far away from the tunnel opening, and the tunnel comprises primary supports 5, a secondary lining 6 and an inverted arch 7. The double-row grouting small guide pipe advanced support comprises a double-row advanced small guide pipe 3 driven into the tunnel face. The drilling angle of the first row of the advanced small guide pipes 3 is 30-35 degrees, and the reinforcing effect and the grouting expanding effect are mainly exerted; the drilling angle of the second row of the leading small guide pipes 3 is 10-15 degrees, and the second row of the leading small guide pipes mainly plays a role of a shed frame. The first row of advanced small guide pipes is constructed firstly, and then the second row of advanced small guide pipes is constructed. One end of each small advanced guide pipe 3 is supported on an unearthed rock body, the other end of each small advanced guide pipe is fixed on the steel arch frame 4, a beam type structure with a supporting point at the front end is formed, and each small advanced guide pipe 3 is a grouting steel pipe.

After drilling, the double-layer advanced small guide pipes are pressed in, grouting pre-reinforcement is carried out on surrounding rocks in front of the palm sub-surface through the advanced small guide pipes, loose rock-soil bodies are consolidated, the compactness of the rock-soil bodies is increased, an integral advanced reinforcing ring is formed along the advancing direction of the tunnel, the self-bearing capacity of the loose surrounding rocks is further enhanced, and the deformation of the surrounding rocks is effectively controlled.

Preferably, each advanced small conduit 3 is reserved with 10cm and firmly welded on the steel arch frame 4, and the hole forming positions of the double rows of advanced small conduits 3 are staggered with each other along the extending direction of the tunnel. The double-row small advancing guide pipe 3 adopts hot-rolled seamless steel pipes with the outer diameter phi 42mm and the wall thickness 4.0mm, the length is 5.0m, the first row comprises 36 pipes, the second row comprises 37 pipes, and the total number of pipes is 73. Before the small guide pipe is used for grouting, primary concrete spraying sealing is carried out on an excavation face, grouting material adopts P.O42.5 cement paste, the water cement ratio is 0.5: 1-1: 1, the actual proportion is determined according to a construction process level field test, and the grouting pressure is 0.5-1.0 Mpa.

In addition, the circumferential distance of each row of the small advancing guide pipes 3 is 40cm, the longitudinal distance is 240cm, and each four steel arches 4 are in one construction cycle.

The front end of each advanced small conduit 3 is processed into a taper shape, a stiffening hoop is welded at the tail part, and quincunx grouting holes with the diameter of 6mm are drilled on the periphery of the conduit wall according to the distance of 15 cm.

Claims

1. The utility model provides a loose body overburden tunnel that collapses goes out hole stable support structure which characterized in that: the device comprises a reinforced sleeve arch arranged at the tunnel portal and a double-row grouting small conduit advanced support arranged along the design contour line of the tunnel; the reinforced type cover arch comprises a cover arch foundation (1) and a cover arch pipe shed (2), the cover arch foundation (1) comprises cement piers (1a) and vertical grouting steel pipes (1b), the two cement piers (1a) are respectively supported under the left end and the right end of the cover arch pipe shed (2), each cement pier (1a) is provided with a plurality of vertical grouting steel pipes (1b) for reinforcement, the lower part of each vertical grouting steel pipe (1b) is inserted into a mountain bedrock, and the upper part of each vertical grouting steel pipe (1b) extends into the corresponding cement pier (1 a); the double-row grouting small conduit advanced support comprises double rows of advanced small conduits (3) driven into a tunnel face, the drilling angle of the first row of advanced small conduits (3) is 30-35 degrees, the drilling angle of the second row of advanced small conduits (3) is 10-15 degrees, one ends of the advanced small conduits (3) are supported on an un-excavated rock body, the other ends of the advanced small conduits are fixed on a steel arch frame (4), a beam type structure with supporting points at the front end is formed, and each advanced small conduit (3) is a grouting steel pipe.

2. A loose collapsed body covering layer tunnel cave-out stable supporting structure as claimed in claim 1, wherein: the length, width and height of the cement piers (1a) are 4m multiplied by 6m multiplied by 1m, the lower parts of the vertical grouting steel pipes (1b) are inserted into the mountain bedrock by 1m, the upper parts of the vertical grouting steel pipes extend into the corresponding cement piers (1a) by 0.5m, the distance between the vertical grouting steel pipes (1b) is 1m, the vertical grouting steel pipes are arranged in 3 rows in the transverse direction, the vertical direction is 5 rows, and 15 cement piers are arranged in a quincunx manner.

3. A loose collapsed body covering layer tunnel cave-out stable supporting structure as claimed in claim 1, wherein: each advanced small conduit (3) is reserved with 10cm and firmly welded on the steel arch frame (4), and the hole forming positions of the double rows of advanced small conduits (3) are mutually staggered along the extending direction of the tunnel.

4. A loose collapsed body cladding tunnel cave-out stabilizing and supporting structure as claimed in claim 1 or 3, wherein: the circumferential distance of each row of the small advancing guide pipes (3) is 40cm, the longitudinal distance of each row of the small advancing guide pipes is 240cm, and each four steel arches (4) form a construction cycle.

5. A loose collapsed body cladding tunnel cave-out stabilizing and supporting structure as claimed in claim 4, wherein: the front end of each small advanced conduit (3) is processed into a taper shape, a stiffening hoop is welded at the tail part, and phi 6mm grouting holes are drilled on the periphery of the conduit wall in a quincunx shape at intervals of 15 cm.