Finite Element Analysis For Bearing And Deformation Of Soil Under Shallow Foundation Subjected To Complex Load

The bearing capacity and settlement of the shallow foundation on soil is the important subject of the soil mechanics and foundation engineering. The ultimate state of the bearing capacity means that the buildings is prevented form inclining, sliping and being destroyed. These formulas is deduced on the basis of the rigidity-plasticity or elasticity -plasticity theoretics supposition. But in the process of deducing, the deformation was never considered. In other words, the settlement and deformation of the foundation are shelved when we are calculating the bearing capacity. The fact that the bearing capacity and settlement is calculated separately is a bad limitation of the bearing capacity theoretics in our country. With the development of the compute technology and the soil constitutive model, the finite element method (FEM) gradually becomes a comprehensively used numerical method in geotechnique engineering. The traditional way of Process-Oriented-Programming has many disadvantages in readability, code use ratio, exploitation period, maintenance and so on. Therefore combination of the finite element method and Object-Oriented programming method has become a tendency in the filed of geotechnical engineering. The Object-Oriented programming of finite element software EPAFCL (Program for Elastic-Plastic Analysis Foundation with Complex Load) is developed. The nonlinear and plastic materials are defined. In the program, the used soil constitutive models include Duncan-Chang constitutive model, K-G model, modified Cambridge model and Drucker—Prager elastoplastic model. On the basis of the bearing capacity at home and abroad, this paper puts emphasis on studying the settlement curve and the soli plastic zone when the uniform and layered shallow foundation is applied by the vertical load and combined load. In the same time, the studying is done with the ANSYS software. Case study show the finite numerical method used in the paper can combine the analyses of the bearing capacity and the settlement of the foundation at the same time and can obtain the nonlinear settlement of the foundation under different load grade and the development of the soil plastic zone and the ultimate bearing capacity of the foundation and can imply the practical mechanism of loaded soil below the shallow foundation under the complex load.