Large cross-section weak surrounding rock tunnel three-step and six-part short-distance construction method

A technology of weak surrounding rock and construction method, applied in tunnels, tunnel lining, earthwork drilling and mining, etc., can solve the problems of poor self-stabilization ability of weak surrounding rock, large deformation of initial support, and slow progress of construction period, etc., to achieve favorable control Deformation, less one-time investment, and large construction space

Active Publication Date: 2014-06-11
CCCC SECOND HIGHWAY ENG CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the construction problems encountered in the current construction of high-speed railway large-section soft surrounding rock tunnels, provide a new construction method, and optimize the traditional three-step sub-section flow operation technology to solve the complex process of the existing technology , the shortcoming of the slow progress of the construction period, overcomes the construction problems such as poor self-stabilization ability of the weak surrounding rock, large initial support deformation, etc., effectively uses resources, saves costs, and realizes safe, fast and economical construction of large-section tunnels

Method used

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  • Large cross-section weak surrounding rock tunnel three-step and six-part short-distance construction method
  • Large cross-section weak surrounding rock tunnel three-step and six-part short-distance construction method
  • Large cross-section weak surrounding rock tunnel three-step and six-part short-distance construction method

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Experimental program
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Effect test

Embodiment 1

[0035] The construction method of three steps and six sections of short-distance construction method for large-section weak surrounding rock tunnels. The excavation section is divided into three steps and six working surfaces. Excavation, support, inversion and filling operations are carried out at the same time. The lining is followed up in time, and the construction of the upper, middle and lower steps is carried out simultaneously, such as figure 1 , figure 2 , image 3 As shown, it mainly includes the following steps:

[0036] (1) Excavate the upper step 1 of the upper arc-shaped pilot pit in a circular direction, and transfer the excavated earthwork from the upper step 1 to the lower step;

[0037] (2) After the upper step 1 lags by 4.5-5m, excavate the left part 2 of the middle step, and transfer the excavated earthwork to the lower step;

[0038] (3) After the left part 2 of the middle step lags behind by 3-4m, excavate the right part 3 of the middle step, and trans...

Embodiment 2

[0044] In step 1, the circular excavation of the upper step 1 of the upper arc-shaped pilot pit is carried out after the advanced support of the arch is carried out by using the steel frame erected in the previous cycle to construct the Φ42 leading small conduit in the tunnel arch.

[0045] The leading small conduit is made of hot-rolled seamless steel pipe with a diameter of Φ42mm and a wall thickness of 3.5mm, with a length of 3.5m and a circumferential spacing of 30-50cm. 12°, can be adjusted according to the actual situation. The drilling direction should be straight. The diameter of the borehole is not less than 45 mm; the small advanced conduits are installed within the 120° range of the arc of the tunnel arch, a total of 38, with a circumferential spacing of 40 cm, and their longitudinal overlap length is not less than 1 meter.

[0046]The excavation contour shape and section size of the upper step 1 should be set out according to the design requirements, and a cer...

Embodiment 3

[0055] The excavation height of the left part 2 of the middle step in step 2 is controlled at 3.3-4m. After the excavation, the initial support of the construction part shall be carried out in time according to the method described in Example 2, that is, the initial spraying of 4cm thick concrete shall be carried out, the steel mesh shall be hung, and the lengthening shall be carried out. Steel frame, and the bottom of the arch foot of the steel frame is close to the edge of the two sides of the steel frame, and the inclination angle is 45° and 60°, and the locking anchor rod 7 is installed. The length of the anchor rod is 4m, and each ring is 8 pieces. 7. It is firmly welded with the steel frame to increase the supporting force of the arch foot.

[0056] In step 3, the excavation height of the right part 3 of the middle step is controlled at 3.3 ~ 4.0m. The method adopted is the same as that of the left part 2 of the middle step. Set up two sets of anchor bolts with inclinati...

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Abstract

The invention discloses a large cross-section weak surrounding rock tunnel three-step and six-part short-distance construction method, which comprises the steps as follows: (1) annularly excavating an upper step of an upper part arc pilot tunnel, transferring excavated earthwork of the upper step to a lower step; (2) excavating a left part of a middle step about 4.5-5 meters behind the upper step, and transferring excavated earthwork to the lower step; (3) excavating a right part of the middle step about 3-4 meters behind the left part of the middle step, and transferring excavated earthwork to the lower step;(4) excavating a left part of the lower step about 6-8 meters behind the left part of the middle step or about 3-4 meters behind the right part of the middle step, and conveying excavated earthwork of the left part of the lower step out of the tunnel; (5) excavating a right part of the lower step about 3-4 meters behind the left part of the lower step, and conveying excavated earthwork of the lower step out of the tunnel; and (6) excavating the rest part of the tunnel bottom about 20-25 meters behind the right part of the lower step, excavating continuously according to the steps in a circulating and interlacing manner, and finally realizing tunnel excavating construction. The method can be used for building a large cross-section tunnel in a safe, rapid and economic manner.

Description

technical field [0001] The invention relates to a tunnel excavation construction method, in particular to a three-step six-part short-distance construction method for a high-speed railway large-section weak geological surrounding rock tunnel. Background technique [0002] In recent years, the country has stepped up the pace of construction of railway passenger dedicated lines in the western region, where there are continuous mountains and complex geology. The number of many long tunnels has increased, and the average line tunnel length occupies 30%-70% of the entire line. The surrounding rock grades of grades IV and V account for a large proportion of the tunnel body geology, and the construction safety risk is high. For the excavation section is 138m 2 -146m 2 For railway tunnels with weak geological surrounding rocks and large excavation sections, reliable construction methods must be adopted to ensure the safety of tunnel construction. [0003] In order to control an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21D9/00E21D11/10
Inventor 夏润禾何建宏许前顺边玉良丰小平李军周云徐向叶
Owner CCCC SECOND HIGHWAY ENG CO LTD
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