The Study On Different Factors Of The Shallow Foundation Ground Failure

Shallow foundation has been widely used in urban construction because of its economic, structure in the form of simple, construction easily and other advantages. But the shallow foundation has multiple accidents which are catastrophic, and the factors are so many and complex.The study on shallow foundation damage is mostly based on the general shear failure, it becomes necessary to summarize various factors on the ground failure modes of shallow foundation, failure mechanism, the displacement characteristics of ground and the ultimate bearing capacity. Based on the strain softening model, shallow plate loading standards as a guide, using the numerical simulation to analysis of how the elastic modulus, cohesion, angle of internal friction, foundation depth, the void in ground soil to affect the ground failure, and compared the simulation results with the theoretical analysis, The following main conclusions can be obtained.(1) The strain softening model has been able to distinguish the mode of the ground failure clearly. As the elastic modulus of the soil increased, the cohesion and the angle of internal friction and the depth of foundation reduced, the punching shear failure transforms into local shear failure, and then transforms into general shear failure.(2) As the elastic modulus increases, the ultimate bearing capacity increases, when the general shear failure occurs, the elastic modulus has no effect on the ultimate bearing capacity. With the cohesion, the angle of internal friction, the depth of foundation increasing, the ultimate bearing capacity increases, the ultimate bearing capacity increased firstly and then leveled off.(3) The effect of the hole on ground failure mainly expresses the effect of the hole position and the diameter. In the case of the general ground failure, seven kinds of hole ground failure mode was summed up.(4) The hole in each horizontal plane which is at different depths from the bottom surface of the foundation, the impact of the hole is maximum when the hole is at the axis of the center of the foundation base, as the distance from the centerline of the foundation farther away, the hole diameter is larger, the impact is more obvious. In the inner hole influential distribution ant any point along the vertical line, the deeper the impact is smaller, the hole diameter is larger, the impact is more obvious. At the same position, the hole diameter is larger, the impact is larger; as the distance from the foundation is smaller, the impact is more obvious.(5) The effect of the hole on the ground failure has the the critical effect of position; the hole diameter is larger, the critical effect of position is farther away from the foundation.This paper provides a new method for the numerical simulation in the shallow foundation ground failure; it has some reference in the study of other geotechnical materials failure. The law that the ultimate bearing capacity are influenced by different factors shows that if we want to improve the bearing capacity greatly, apart from improving certain kind of soil parameters, we must also ensure that the basis to meet deformation requirements; it has certain engineering significance to prevent the occurrence of a hole ground failure.