Abstract：Based on the results of test，monitoring and analysis of the underground engineering of Xiaowan Hydropower Station in China，a generalized model for geology and construction process is established. By combination of computing schemes of uniform design method with basic mechanical parameters and initial stress field as basic variables，the three-dimensional elastoplastic finite element method is used to simulate the excavation of underground major plant considering the effect of excavation unloading，and the basic mechanical parameters and initial stress field are obtained by multivariate linear regression method. The coincidence between the back analysis and the testing data indicates that the obtained mechanical parameters and initial stress field are reasonable，and the uniform design method can be used in displacement back analysis of underground engineering.
