Study On Mechanic Behaviour And Failure Mode Of Circular Foundation In Rock Subgrade

In recent construction, circular foundations in rock subgrade subjected to large loading have been adopted more frequently. The design methods for circular foundation in current specifications are all from theories based on soil, and the methods are very rough. The stress field of spread foundations was not considered.Because the rock subgrade has obvious characteristics of high capacity, high rigidity and little distortion, There are some shortage in theory and in practice of circular foundations in rock subgrade, especially it's internal stress field and failure mode.In this article, by methods of theoretical analysis, field test and ANSYS FEM numerical analysis, some researches have been done to the subgrade reaction's distribution of circular foundation in rock, internal stress field in circular foundation, the failure mode of circular foundation in rock subgrade. The main work and efforts are as follows:â‘ For the circular foundations in rock subgrade, regardless of the physical load, look as axisymmetric space problems. From the homogeneous lame equation, adopting spatial cylindrical coordinates, use the general equation solution of Boussinesq-Galerkin, through the test taken Love strain function, checking the four accurate boundary conditions of circular independent foundation, finally we got the theoretical solution of internal stress field in circular foundation on rock subgrade.â‘¡According to test results and test phenomenon, it summarizes the subgrade reaction's distribution of circular foundation in rock subgrade, form relevant tables and curves, gets the rule of distribution curve of subgrade reaction. The subgrade reaction's distribution is nonlinear significant, it is intermediate small and uniform, both sides big. Due to stress concentration and stress redistribution, the distribution to the edge of the foundation decreases. But the subgrade reaction's distribution is uniform linear distribution in current specifications. For the general rock subgrade, there are some difference between specifications and actual engineering.â‘¢Based on ANSYS FEM numerical analysis, we got the internal stress field in circular foundation. Contrast the theoretical calculation, Summarized the trend of internal stress field in circular foundation. Contrast the field test results, Summarized the failure mode of circular foundation.Both of them provides the theory basis for circular foundation's design method in engineering.The research results about circular foundations in rock subgrade in this article, have its own value both in theoretical research and in engineering applications.