Tunnel Primary Support Structure and Construction Method

Abstract

The invention discloses an initial support structure and construction method of a tunnel, which actively provides support resistance for the surrounding rock early and actively through the shotcrete support outer layer that is offset against the wall surface of the surrounding rock of the tunnel, and reinforces the surrounding rock from the inside to prevent extrusion Rapid expansion of the plastic zone of surrounding rock; the deformation pressure on the outer layer of the shotcrete support is evenly transmitted to the inner layer of the shotcrete support through the intermediate elastic buffer layer with a certain radial elastic deformation capacity, and at the same time, it meets the requirements of the shotcrete support. The arc-shaped support sections distributed at intervals in the inner layer can be freely compressed in the annular direction, and provide constant resistance to the two adjacent arc-shaped support sections at intervals in the circumferential direction through the constant resistance energy release device, so as to realize shotcrete support The compression deformation of the inner layer under constant resistance can continuously and stably release the plastic energy in the surrounding rock, until the plastic energy in the surrounding rock is released, the deformation convergence of the surrounding rock and the supporting structure can be stabilized.

Description

technical field [0001] The invention relates to the technical field of tunnel engineering construction, in particular to a tunnel primary support structure and a construction method. Background technique [0002] my country is in the period of rapid development of tunnel engineering construction to extremely complex geological fields. For example, the Kangding-Linzhi section of the Sichuan-Tibet Railway, which is about to start construction, will cross the section with complex geological conditions and densely developed deep active faults in the world. Among them, there are 14 tunnels exceeding 20km, with a total length of 392km; the longest tunnel, the Yigong Tunnel, has a total length of 42.486km, and the Layue Tunnel, the largest buried tunnel, is as deep as 2096m. [0003] Tunnels often encounter large deformation problems when passing through such large-deep extruded surrounding rock sections, which are mainly manifested in the continuous large deformation of the surrou...

AI Technical Summary

Problems solved by technology

However, there are still deficiencies. The reason is that the tubular or plate-shaped damping elements mainly control the release of plastic energy of the surrounding rock through compression deformation in the direction of force and provide elastic resistance, but they lack early support resistance for the surrounding rock and The ability to actively control the continuous expansion of the plastic zone of the surrounding rock from the internal reinforcement of the surrounding rock. At the same time, the resistance provided by the circular tube or straight plate is constantly changing during the compression deformation process, so the damping element cannot be controlled during the compression deformation process. Stable Release of Plastic Energy of Surrounding Rock

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