Abstract: According to the statistical data of a large-scale project in Yunnan Plateau, a typical karst cave model covered with clay was established by employing ANSYS and FLAC3D, and the ultimate bearing capacity of foundation was calculated and its regularities were summarized in the presence of varying cohesion, internal friction angle, tensile strength, thickness of roof, depth-span ratio, cave radius, and cave width. Furthermore, through orthogonal analysis and rough set theory, the influences of these factors on the ultimate bearing capacity of the foundation were analyzed. Results reveal that roof thickness and shear strength have the biggest influence on the ultimate bearing capacity, followed by cave radius, depth-span ratio and cave width, while tensile strength has the smallest impact.

Key words: covered karst, ultimate bearing capacity of foundation, numerical analysis, orthogonal analysis, rough set theory