Experimental Study On Stability Of Surrounding Rock Mass Controlled By Faults In Tunnel Projects

A large number of engineering practice shows that the fault of the stability of surrounding rock of underground caverns have a decisive impact on the role, it carried out the impact of faults on the stability of the rock failure mechanism model test is very meaningful.In this paper, combined with the physical structure of the China Seismological Bureau Laboratory Fund "deep impact on hard rock in the surrounding rock by the tectonic instability of the breakdown of the process of research" subjects, with 45-degree angle to the true fault sandstone tunnel posed by the objectives for the study using the physical model test and numerical simulation methods, with fault on the tunnel in the mechanism of progressive failure under external force conducted an in-depth studies, research findings and conclusions are as follows:Firstly, through uniaxial compression tests, was used in this experiment, the physical and mechanical parameters of sandstone.Secondly, through the test and found that 400×400×50mm sandstone samples, such as in the ratio of 1:3, such as displacement control loading conditions, the pressure in the press very difficult to achieve the destruction of the framework. It is loaded for the horizontal adjustment of load control, load control vertical displacement.Thridly, When the tunnel does not support the case, the form of rock damage to brittle fracture. Mainly occurred along the fault dislocation. When the tunnel under the conditions of support, rock damage to the form of obvious strain-softening stage. And location in the vault, and its destruction is more development of cracks. And through the laid surface strain gauge 92 to conduct a detailed analysis of the data, we found that as time goes by, the surrounding rock stress field is changing, and fault of the strain field have a certain influence. The acoustic emission of rock for analysis and found that this type of rock acoustic emission Mogi-I type. Coefficient of strain sensitivity to the concept of vertical strain on the surrounding rock for analysis.Fourthly, the use of RFPA-2D finite element software to simulate the progressive failure process of rock tunnels, through its stress field and a comprehensive comparative analysis of acoustic emission have been a number of laws to undermine the form of rock from the tunnel as the faults of the distance between contour lines differ, fault from the tunnel contour lines within a certain scope, the fault with the tunnel between the contour stress concentration area, and the deformation of the tunnel to the fault direction.