Abstract: In order to analyze the influence of geostress on the stability of karst cave, a geostress model was developed based on the geostress database in China and the geostress formula in the research region. In-situ measurement was executed to bridge the gap between the geostress model and the engineering application. For the convince of evaluating the magnitude of shear stress and plastic zone, the karst cave was modeled through the finite difference software with applications of the geostress model and Hoek-Brown yield criterion. Special attention is paid to the stability evaluation of the karst cave under various geostress conditions during modelling. Several beneficial consequences obtained from the evaluation suggest that the role of the geostress condition is quite important in influencing the stability of karst cave. The geostress is decomposed into the mean stress and the shear stress for the sake of exploring its explicit influcement. An empirical equation was summarized via regression analysis to explicitly depict the approximately linear relationship between the ratio between the mean stress and the shear stress and the capability of karst cave. An in-situ investigation considering the collapse site and the ultimate subgrade height was conducted to compare with the numerical results. The results suggest that a reasonable consideration of geostress is necessary for evaluating the stability of karst cave.

Key words: karst cave, stability, geostress, plasticity