Long and short yielding anchor rod type combined control method suitable for large deformation of soft rock tunnel

Abstract

The invention discloses a long and short yielding anchor rod type combined control method suitable for large deformation of a soft rock tunnel. The method comprises the steps of upper step construction of the soft rock tunnel and lower step construction of the soft rock tunnel. According to the method, after tunnel excavation is completed, guniting treatment is carried out on a surrounding rock in time, the exposure time of the surrounding rock is shortened, then installation of a reinforcing mesh and yielding anchor rods are carried out, the yielding anchor rods are arranged in two times, setting of a primary support steel frame is carried out, and finally a layer of concrete is sprayed again; and releasing can be carried out on the internal energy of the surrounding rock in a deformation mode, firstly, the force acts on the yielding anchor rods, when the supporting force provided by the yielding anchor rods and a steel arch is equal to the deformation force of the surrounding rock, the deformation of the surrounding rock stops, at the moment, a primary supporting system composed of the yielding anchor rods and the steel arch is in a relative balance state, the rigid-flexible combined supporting effect is formed, engineering accidents caused by large deformation are avoided, and the method has the advantages of being good in surrounding rock supporting effect, simple in supporting structure and economical in material consumption.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering support, in particular to a joint control method of long and short yield bolts suitable for large deformation of soft rock tunnels. Background technique [0002] With the continuous development of my country's transportation industry, the burial depth of tunnels is getting larger and larger, and the geology of the rock formations they pass through is becoming more and more complex. Large deformations and landslides are very easy to occur during the process. For example, Dalian-Xinjiang High-speed Railway Daliang Tunnel, Lanzhou-Chongqing Railway Maoyushan Tunnel, Lanzhou-Chongqing Railway Liangshui Tunnel, etc. have all had the above problems, which brought great danger to the construction of the project. Moreover, after the initial support is applied, problems such as steel frame deformation are prone to occur, and arches need to be replaced, which greatly increases construction co...

AI Technical Summary

Problems solved by technology

[0002] With the continuous development of my country's transportation industry, the burial depth of tunnels is getting larger and larger, and the geology of the rock formations they pass through is becoming more and more complex. Large deformations and landslides are very easy to occur during the process. For example, Dalian-Xinjiang High-speed Railway Daliang Tunnel, Lanzhou-Chongqing Railway Maoyushan Tunnel, Lanzhou-Chongqing Railway Liangshui Tunnel, etc. have all had the above problems, which brought great danger to the construction of the project. Moreover, after the initial support is applied, problems such as steel frame deformation are prone to occur, and arches need to be replaced, which greatly increases construction costs and project progress;

[0003] In order to effectively control the large deformation of the surrounding rock during construction, scholars at home and abroad have conducted in-depth discussions on the causes of the actual large deformation of the tunnel. The basic method used in the current project is to apply double-layer primary support or increase the type of steel frame. Theoretically speaking, these methods are uneconomical. The most suitable method is to use a combination of rigidity and flexibility to release part of the energy of the surrounding rock through deformation, but it must also be limited. Excessive deformation, so an improved solution to the deficiencies of the existing technology is needed

Images