Application Of Displacement Inverse Analysis To Rockmass Parameters Of Xiganchi Tunnel And Support Optimization

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. 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, which will directly affect the design and optimized scheme establishment. 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. It can provide reliable parameters for the tunnel construction, design-optimizing and certain prediction.On the base of massive research, this paper takes the project of Xi Ganchi 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 FLAC3D. The parameters include elastic modulus( E ) , poisson ratio(μ), internal friction angle(? ) and cohesion(C ). The main work includes:1. Combined with the engineering geological condition, geology and structure, hydrogeological condition and rock mechanics tests, do the engineering geological assessment.2. Taking the circular tunnel for example, analysis and deduce the distributions of stress and displacement in the rock-mass at second elastic and plastic states and under the condition of interact of rock-mass and support. Provide the academic base for this paper.3. Introduce the theory and method of FLAC3D in short, chose HD12+570~HD12+770 section to establish the model and simulate the tunnel construction and support, make certain the extent of parameters according to the tests and related criterions and array the parameters based on orthogonal design principle. Take the in-site monitoring data as reference, input the orthogonal designed parameters to the model one by one and simulate the tunnel construction, gain the rock-mass parameters.4. Input the inversion analysis parameters to the model again, compare the simulated displacement with the other monitoring data of this section, validate the reliable of the results.5. According to the in-site monitoring displacement data and simulated displacement data, optimize the cable support designer.