The Inverse Analysis To Rockmass Parameters And 3D Finite Element Analysis Of Construction Process For Hydraulic Tunnel

With the steady and fast development of national economy and technology, the government expands the investment to infrastructure construction and pays more and more attention to tunnel engineering. For the tunnel engineering, it is a key to select rational parameter of rock which tunnel is laid in, which will directly affect the reliability and security in design and construction.As for the tunnel laid in more complicated geological area, the rock-mass and soil-body behave great fuzziness, uncertainty and randomness, so it is difficult to ascertain parameter of rock and soil exactly.At present, we can gain parameter of rock which tunnel is laid in through site testing. Site testing is not only hard to carry out, but also have great distinction in different areas.On the basis of massive researches, making use of the in site monitoring data of the rock-mass displacement and stresses change to analysis the actual rock-mass parameters can gain more rational results.This paper takes the project of Wanzi tunnel construction for example, make use of in-site monitoring data of rock-mass displacement and the inversion analysis method to gain the rock-mass parameters with PSO invoking finite element software ANSYS. On this basis, simulated and calculated the tunnel excavation, shotcreting-bolting support and secondary lining. In this paper, the author has done primarily the following work:(1) Introduce the principle and method of ANSYS software in short, chose 6+890~6+920 section to establish the finite element plane model and three-dimensional model.(2) The inversion method based on PSO invoking ANSYS was proposed. Make use of the inversion analysis method which is based on my own C language invoking APDL command to simulate and calculate the roke-mass's elastic modulus. This method use PSO's powerful overall search ability which can effectively solve the difficult problems of derivation and easily falls into a local extremum point.(3) This inversion calculation also inverted the element weakening coefficient while it inverted the tunnel roke-mass's elastic modulus. The roke-mass"reversed force"in tunnel excavation is simulated by using element weakening theory to simplify the finite element model and reduce the human error in calculations.(4) A three-dimensional finite element model was built in tunnel construction. Input the inversion analysis parameters to the model, simulate the tunnel excavation, shotcreting-bolting support and lining construction. By analyzing the changes of displacement and stress of rock-mass and lining in every construction step to again the law of development. At the same time, the security of tunnel secondary lining's structural size was verified.(5) The paper summaries the whole research, analyzes the shortcomings and limitations of the research and puts forward to the main research aspects in future.