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Abstract In the construction of large underground caverns，high geostress has become the key factor which affect the stability of surrounding rock after excavation. In order to ensure the stability of surrounding rock and to evaluate the effect of supporting design，back analysis of initial geostress field is needed. By studying the distribution and the calculation method of initial geostress field，it was found that the distribution of initial geostress field influenced by the spatial location and boundary conditions was highly consistent with the regionalized variable theory of variogram function，thus a statistical method of back analysis on initial geostress field was proposed based on the variogram function. The reasonable expression of regionalized variable was studied based on two essential factors of spatial distance and depth. The parameters of spherical model suitable for back analysis of initial geostress field in underground engineering was obtained by fitting analysis with the least square method. Applying the spherical model and data of measured points，the initial geostress field was interpolated，which reflected the influence of topography. Furthermore，with the theory of incremental and varied plasticity stiffness，the excavation process of underground powerhouse was simulated and the distribution of displacement and the plastic yield areas agreed with the measured value.
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2015, Vol. 34 
