Research Of Subsoil Bearing Capacity Considering Unilateral Surcharge

The traditional calculation formula of subsoil critical load is applicable to the case of symmetrical surcharge, which can not be used in the case of unsymmetrical surcharge. In this paper, based on the form of unilateral surcharge, the critical load of the foundation is derived and calculated, and the additional stress and the critical load of the subsoil are derived and calculated. And the formula is verified and compared with the traditional theoretical formula. By the model tests to study on the influence of unilateral surcharge in subsoil bearing capacity characteristics under non surcharge case and unilateral surcharge case.The following work has been carried out and the relevant conclusions are obtained:Based on the MATLAB software, this paper follows the derivation method of traditional critical load, and derived and calculated the subsoil additional stress and critical load in condition of one side surcharge. The calculated results indicate that the one side surcharge enlarge the influence range of additional stress, and offset to one side with surcharge. Under the one side surcharge and critical load, the subsoil plastic zone is no longer symmetrical, and only appeared in the opposite side subsoil of the surcharge. Analysis show that the influence of one side surcharge on the critical load of the foundation is limited and it can be neglected. This conclusion also validate quantitatively the specification of "code for design of building foundation"(GB50007-2011) on subsoil critical load under the case of unsymmetrical surcharge.This paper first test the relative physical indexes of sand to understand the basic properties of sand. In addition, the laboratory model load test is carried out on the non embedded depth strip foundation. Piled on foundation on side of the subsoil with different magnitude of surcharge. The results show that the bearing capacity is obviously improved and the settlement of subsoil is obviously restrained under the unilateral surcharge case than the case without surcharge. The vertical stress distribution of subsoil is no longer symmetrical, stress in the surcharge side has increased. The shear failure of the subsoil is asymmetric. Failure zone length is shorter,and the subsoil on one side of the surcharge uplifts less. Theoretically, the experiment results contribute to the research of subsoil bearing capacity and the vertical stress distribution as well as the failure mechanism considering unilateral surcharge. The test results agree well with the theoretical results mentioned above.