Cavern Stochastic Finite Element Analysis And Reliability Calculations

Finite element, as a method of structural stress and stain analysis, apply to actual projects widely such as the building construction, water and electricity, mine, etc. The stochastic factors of the objective reality enable the response (including the stress of the structure, meets an emergency) becomes stochastic. The safety coefficient law, as a traditional means, it is difficult to take the stochastic factors of loading and parameter into account. The stochastic finite element law carries on reliability analysis of structure in terms of probability analysis, so it is good at the security evaluation of the structure and it is widely used in actual project as a strong number value and analyzed tools.The purpose of law of stochastic finite element can be roughly come down to three points: solving the stochastic response of the structure under the influence of stochastic factor, calculating the reliability of the structure and obtain sensitivity of the design parameter to structural security.Based on the research of Professor Liu Ning (Hohai university), this paper discuss the excavate simulation and reliability of the underground cavity's wall rock deeply. The ground stress distribution is the main factor that affects the reliability of the wall rock, so taking the non-determinacy of the ground stress into account, the probability analysis of the ground stress distribution is discussed in detail. During the simulation of the strengthen effect that introduced by anchors, taking the non-determinacy of the separation and the material character of anchors into account, the stochastic analysis method of the strengthen effect is presented, which provide the foundation for the security analysis of the wall rock with anchors. The seep loading is one of the main loadings that affect the stability of the wall rock, so a simplified model is presented to illustrate the effect of the seep loading's randomness. Moreover, the sensitivity of the reliability of the wall rock to the parameters of various materials and the ground stress coefficient is discussed.In the aspect of the utility, the three-dimensional simulation of the a certain tube's excavation process is present by the ANSYS plat, and then the wall rock displacement, stress and shoring internal force is discussed. Finally, the reality of the reliability analysis by the ANSYS plat is discussed to prove the advance of the stochastic finite element method.