Spatial effect of the excavation disturbed zone (EDZ) around complex underground openings is evident and hardly identified with the formation and development. Generally, the characteristics of the EDZ are behaved as the deterioration of the deformation modulus of the surrounding rock. In order to analyze the spatial effect of the EDZ, by considering the limited application of the pressure or radius dependent Young’s modulus model based on the elasticity analysis of the thick-walled hollow cylinder, a numerical model of the EDZ using radius-displacement-dependent deformation modulus was proposed for complex openings. And the applicability to multi-caverns and parameter sensitivity of the model were basically analyzed with synthetic data. This model is actually a parameter field model, which can be used to reveal the spatial effect of the EDZ on the working state by quantifying the deterioration of the deformation modulus. The model was further studied by its application in the large underground powerhouse of Pubugou Hydropower Plant. The spatial effect of EDZ and impact on stability were analyzed through parametric analysis using the model. The deterioration parameter field along the longitudinal axis of main powerhouse was evidently non-homogeneous in space and distributed as exponential along the radius from the opening. It was indicated that the model provides a numerical method with rationality to evaluate the deformation modulus of EDZ, and the parametric analysis method to analyze the spatial effect of EDZ is of reasonable applicability to the rapid feedback for the underground construction process,the stability assessment of the surrounding rock and providing scientific basis of support optimization.
