Tunnel primary supporting structure and construction method

Abstract

The invention discloses a tunnel primary supporting structure and a construction method. Supporting resistance is actively provided for surrounding rock as soon as possible through a sprayed concretesupporting outer layer abutting against the wall face of the tunnel surrounding rock, the surrounding rock is reinforced from the interior, and the plastic zone range of the extruded surrounding rockis prevented from being rapidly expanded; and deformation pressure borne by the sprayed concrete supporting outer layer is evenly transmitted to a sprayed concrete supporting inner layer through a middle elastic buffer layer with certain radial elastic deformation capacity, meanwhile, arc-shaped supporting sections annularly distributed on the sprayed concrete supporting inner layer at intervals can be annularly and freely compressed, constant resistance is provided for every two annularly-spaced adjacent arc-shaped supporting sections through a constant-resistance energy releasing device, compression deformation of the sprayed concrete supporting inner layer under the constant resistance is achieved, and therefore plastic energy in the surrounding rock is continuously and stably releasedtill the plastic energy in the surrounding rock is completely released, and deformation convergence of the surrounding rock and the supporting structure tends to be stable.

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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