Bearing Capacity Of Spreading Foundationon Finite Element And Plastic Hinge Theory Analysis

Because of the rock foundation has the characteristics of high bearing capacity, high stiffness and small deformation, the foundation reaction and mechanic behavior of foundation on rock are different from that on soil foundation. There will be some obvious unreasonable if the single-column footings(SCF) in rock foundation is designed by according to the specification.In this article,by methods of ANSYS FEM numerical analysis study Elastic Modulus of rocks,basic cross ratio,reinforcement on the bottom base effect on sectional shear,counter-force distribution base,foundation cracks develop,ultimate bearing capacity of the foundation.The main work and efforts are as follows:? According to finite element results,shear values can be obtained at the basis of different section. It found that the shear value is approximately linearly increased on the basis of the center to the edge of the column cross-section-wide basis. The shear values decreased nonlinearly in a column to the inner edge of the base edge of the scope of basic cross-section,reduced speed from fast to slow and finally flatten. Shear maximum in the column where the junction with the base section. Shear maximum in the column where the junction with the base section.Under the same load,as the elastic modulus of the rock increases and decreases across basis,the basis of the maximum cross-sectional shear decreases.? According to finite element results,reacting Force Distribution can be found on the rock foundation of Base exhibit highly nonlinear. BASE REACTION overall trend decreases from the base to the base on both sides of the bottom center. And it has increased in the edge of the base.Substrate reaction profile was "M" shape.Under the same load,with the increase of base across higher than the elastic modulus of rock increases.Base reaction force to focus on the basis of the center so basic reaction force distribution is more uniform.? According to finite element results,we can draw independent foundation cracks first appeared under axial loads at the bottom center of the base. As the load increases the axial cracks in the foundation base and the top edge along the symmetrical basis for development,and ultimately the formation of cracks penetrating. When the rock foundation stiffness increases than decreases across the base,base load when the first crack has increased.? According to finite element results,we found that with the increase of steel reinforced concrete near the strain has a certain binding effect,but no effect on the Shear basis and foundation of the ultimate load basis. Modulus of elasticity of the rock group larger than the smaller cross base,the greater the ultimate bearing capacity of the foundation.? FEM calculation results and plastic hinge theory analysis and standardize the calculation results were compared. Reaction force based specification assumes a uniform distribution of the substrate. With the guaranteed safety redundancy,the use of finite element results to fit on the ground and foundation stiffness ratio, higher than the basic cross-checking formula based Shear.