Support change process of second liner construction of large-cross-section tunnel

Abstract

The invention discloses a support change process of second liner construction of a large-cross-section tunnel. The support change process comprises the following steps of: (1) pre-burying a first support-changing steel plate on the top surface before backfill of an inverted arch of a left lower hole; (2) removing the end part of a temporary vertical support by cutting first, welding the end part of the temporary vertical support on the first support-changing steel plate by using I-shaped steel, and connecting the temporary vertical support with backfill concrete, wherein the next support can be changed after the last support is well connected; (3) pre-burying a second support-changing steel plate before casting of second liner concrete on a lower side wall, removing the end part of a temporary transverse support by cutting after the casting of a second liner of the lower side wall and demolding are finished, welding the end part of the temporary transverse support on the second support-changing steel plate by using I-shaped steel and connecting the temporary transverse support with second liner concrete, wherein the next support can be changed after the last support is well connected; (4) constructing a second liner of a right upper hole and a second liner of a left upper hole; and (5) after the strength of the second liner concrete reaches 75 percent, gradually removing the temporary transverse support and the temporary vertical support. According to the support change mode, after the end part of the temporary transverse support or vertical support is removed, the stability is improved and the smooth construction can be ensured.

Description

Technical field [0001] The invention relates to the technical field of tunnel construction, and more specifically, to a support replacement process for the second lining construction of a large-section tunnel. Background technique [0002] In recent years, with the rapid development of rail transit and underground space construction in major cities in China, builders have also improved their grasp and application of underground tunnel construction technology. Common construction methods include full-section method, step method, and CD Method (in a large-span tunnel with weak surrounding rock, firstly excavate one side of the tunnel and construct the middle wall, and then excavate the other side separately), CRD method (a large-span tunnel with weak surrounding rock) In the tunnel, first excavate one side of the tunnel in sections, construct the middle wall and diaphragm, and then excavate the other side of the tunnel separately to complete the construction of the diaphragm. The c...

AI Technical Summary

Problems solved by technology

[0006] According to the conventional construction procedures, after the construction of one side of the tunnel, the ends of the temporary horizontal braces or vertical braces need to be removed, but after the removal of the ends of the temporary horizontal braces or vertical braces, the tunnel will become an unstable structure, unable to carry out construction

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