Excavation Method of Combined Section Steel Temporary Support for Extra Large Section Tunnel

Abstract

The invention discloses a combined steel temporary supporting excavation method for a tunnel with an extra-large section. The combined steel temporary supporting excavation method comprises the following steps of: firstly excavating and supporting left and right upper pilot tunnels; secondly excavating and supporting left and right middle pilot tunnels, and left and right lower pilot tunnels, and excavating a pilot tunnel on the left lower part of the tunnel section; thirdly, setting temporary mid-partition supports and temporary steel supports for all parts; and finally, dismounting the temporary combined upright post steel supports of the left upper pilot tunnel and the right upper pilot tunnel, and pouring the second liner reinforced concrete, excavating core soil and carrying out inverted arch construction to the middle part of the tunnel. The combined steel temporary supporting excavation method uses a combined steel support to replace a temporary excavation method of the core soil, solves the technical difficulties that the excavation period is long, the construction quality cannot be ensured, the construction is difficult, and the like, and also solves the technical problems of ensuring the quick construction for the super-large section and the construction quality. A steel truss is used to replace the construction for the upper core soil, so that not only the construction safety of the tunnel can be improved, but also the tunnel excavation and the support speed can be quickened.

Description

technical field [0001] The invention relates to an engineering construction method, in particular to an excavation method for temporary support of combined section steel for super-large section tunnels. Background technique [0002] For large-section tunnels located in the center of downtown and shallow buried and underground excavated, safe construction is the key point. The common excavation method of super-large cross-section underground excavation tunnel is to divide the large cross-section into left and right side walls, and carry out in sections. This construction method mainly divides the excavation of the tunnel into nine times for excavation. The excavation of this excavation method can ensure the safety of the excavation, but there are the following disadvantages: 1. There are many excavation procedures, the construction procedures are complicated, and the construction period long. 2. The quality is difficult to be guaranteed: because the left and right double gu...

AI Technical Summary

Problems solved by technology

This construction method mainly divides the excavation of the tunnel into nine times for excavation. The excavation of this excavation method can ensure the safety of the excavation, but there are the following disadvantages: 1. There are many excavation procedures, the construction procedures are complicated, and the construction period long

2. The quality is difficult to be guaranteed: because the left and right double guide pits are separated by the core soil and closed into a ring arch, it is difficult to keep on the same straight line when the core soil is excavated, resulting in sometimes the arch cannot be closed; 3. It is not conducive to the excavation and transportation of slag in the tunnel, because the excavation section of the pilot pit is narrow, and the vehicle organization is extremely difficult

Due to the many construction procedures of the double-side-wall pilot pit method for super-large-section tunnels, the steel arch frame of each section is difficult to close into a ring, the quality cannot be guaranteed, and the construction organization is difficult.

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