High ground stress weak surrounding rock tunnel excavation and support construction method

Abstract

The invention discloses a high ground stress weak surrounding rock tunnel excavation and support construction method. Excavation and support construction are conducted on a weak surrounding rock tunnel to be constructed in multiple sections from rear to front in the longitudinal extension direction of the tunnel. The method comprises the steps that 1, rock body strength and the maximum ground stress inside surrounding rock are tested; 2, the extrusion-type large-deformation level of the surrounding rock is determined; 3, a primary support scheme is determined, wherein the primary support scheme is determined according to the determined extrusion-type large-deformation level, and the primary support scheme is a profile steel frame support scheme or a grid steel frame and cover arch combined support scheme; 4, tunnel excavation and support construction are conducted; 5, excavation and support construction of the next section are conducted; 6, the fifth step is repeated for many times till the whole excavation and support construction process of the weak surrounding rock tunnel to be constructed is completed. According to the high ground stress weak surrounding rock tunnel excavation and support construction method, the steps are simple, the design is reasonable, construction is convenient, the use effect is good, the tunnel excavation and support construction process of the high ground stress weak rock tunnel can be completed easily, conveniently and rapidly, and the construction process is safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to an excavation and support construction method for a tunnel with high ground stress and weak surrounding rock. Background technique [0002] Tunnel excavation will inevitably lead to the redistribution of the original stress of the surrounding rock. The mechanical behavior of the stress redistribution of the entire surrounding rock can be generalized as the following process: balance. "Looseness" and "looseness" are two completely different concepts in describing the process of stress redistribution, and the manifestations of surrounding rock loads in these two processes are also different. The load generated in the "relaxation" stage is called "deformation pressure". At this time, the reduction of the stress level of the surrounding rock and the deformation of the surrounding rock coexist. From the perspective of rock mechanics, the surrounding rock at th...

AI Technical Summary

Problems solved by technology

[0019] Third, the large amount of deformation, rapid development and continuous non-convergence, it is very common for the supporting system after construction to be intruded due to poor control of the deformation amount;

[0020] Fourth, the amount of deformation reserved for excavation cannot be scientifically and accurately predicted. If it is too large to increase the excavation section of the tunnel, it will not only be detrimental to the stability of the surrounding rock, but also cause serious waste because the deformation cannot be reached; if it is too small, if the excessive deformation invades limit, resulting in safety risks and waste of replacement

Images