The Factors Analysis Of Underground Cavity Broken Zone

With the development of economic construction, exploration and utilization of the underground space is more and more extensive. When people utilize the underground space, the original force balance of rock will be destroyed to some extent. Thus, underground engineering stability problems is one of the priority subjects of the geotechnical engineering research field. Broken zone is a stress state changed and formation layer cycle which the cavity rock is excavated. The determination of broken zone is an important part in repair liner and support of the cavity rock. The broken zone thickness is related with many factors. This paper focused on the research for the factors of the underground cavity broken zone. The main work completed follows as:1. It summarizes the history and the present state of the research on the theory of broken zone and introduces the main research methods briefly, introduces in detail reviews the theory of broken zone and the surrounding rock pressure calculation as well as the determination method of the broken zone thickness scope.2. It combines with the stability analysis calculation of the cavity, learning and developing the large calculation software, introducing the basic principle, characteristic, function and operation. It researches in detail the application and common command of FLAC3D in the determination broken zone.3. On foundation of the numerical analysis calculation with FLAC3D software, it researches in detail the rock physical parameters, the surrounding pressure and the cavity shape influence on broken zone thickness.4. With the numerical simulation calculation determines the broken zone thickness value on the different conditions. It establishes the relationship among the broken zone thickness and the rock stress, the cohesive force, friction angle, cross-high rate of cavity, through hypothesis testing.