Computation on The Stability of Soil Cave Foundation Under The Role of Building Load in Karst Area

Soil cave foundation is common in Karst area, which damage would impact the stability of the foundation. Currently, the qualitative analysis of the collapsed mechanism has been done, but few of quantitative. Based on the theory of elasticity and plasticity, the stress condition and influence circle of concentration around the cave is researched. The calculated model of stability of the foundation is modified by Mohr-Coulomb criterion. The feasibility and reliability is proved by the example of the cave foundation in Guizhou province. And researched the effect of size, depth of the foundation, shape of the cave and depth of groundwater to the stress of causing damage or not. The result shows that the radius of influence of stress is 6 times of the vertical length of semi-minor axis and the modified model is feasible. The collapsed stress is higher as larger, deeper of the foundation, flatter of the sharp, deeper of the groundwater. The stress of resisting collapse is lower as deeper of the groundwater, which is the only factor. The influence of that is sensitive to the stability, which the cave would fail at the groundwater declining in small amplitude. Therefore, attention should be paid to the effect of groundwater. And it is significant to guide the prevention of the foundation that is the size, critical depth of the base, and depth of the groundwater.