Sensitivity Analysis Of The Nonlinear Stability Of Underground Caverns

With the rapid development of China’s economy, science and technology, transportation, hydropower, water conservancy, city underground traffic and space utilization, for underground engineering in difficulty and quality put forward higher requirements. In recent years, in order to meet the needs of the rapid development of society and economy, the underground cavern in various applications around the world construction rapid development, its main forms and the development trend of the depth and the length of the tunnel is increasing. Due to underground excavation compared with common civil construction, involving many uncertain factors, such as geological conditions, temperature, making the underground excavation construction may be encountered such as high external water pressure and high pressure water gushing, high ground stress and rock burst, high temperature, high gas and harmful gas and a series of geological disasters, these problems become a major constraining factor in the rapid development of the construction of deep buried tunnel. Therefore, is very important to analyze the stability of surrounding rock of underground caverns.In this paper, with the FEM software ANSYS as the basis, establish the inside without pressure tunnel, mainly studies the stress characteristics of surrounding rock stability of tunnel excavation and lining concrete, specific do the following:Firstly, based on the large finite element software ANSYS, established the city-gate water tunnel, with the D-P criterion, the nonlinear computation of water conveyance tunnel,obtaining the stress characteristic of the surrounding rock of tunnel gate type, development of plastic zone characteristics. And the displacement of surrounding rock and stress sensitivity are analyzed, the stability of surrounding rock and the lateral pressure coefficient, internal friction angle, cohesion, and careful analysis of the development of plastic zone and plastic strain and coefficient of horizontal pressure, internal friction angle, the cohesion of the relationship.Then calculate the stress characteristic of the city the gate type hydraulic tunnel lining, finding out the maximum stress of the lining of area, analysis the influence of thickness of the lining of internal force of lining. The results show that the lining at the bottom of the wall, the thickness of lining and lining stress is larger, the result has certain significance to the practical engineering.