Analysis And Research On Accident Of Multiple-story Building On Soft Foundation Soil

Settlement of foundation soil, especially differential settlement, is one of the general cause of construction accident in civil engineering and construction engineering. Differential settlement of foundation not only badly influences employment of buildings and constructions, but also causes damage on the upper structures to some extent or even arouse structures to collapse.When designing structural projects of buildings, we are accustomed to consider the mechanical performances of upper structure, foundation and foundation soil independently. Though this analysis method can meet static balance boundary condition, it ignores the continuous deformation relation that lies in the upper structure, the foundation and the foundation soil. The actual state of engineering is that the upper structure, the foundation and the foundation soil are united as a whole to share the deformation. Then the three parts assumes a part of the total deformation according to each rigidity, therefore the internal force and deformation of the whole system will vary to some extent. Thereby when the foundation soil is comparatively soft and feeble or upper structure is sensitive to differential settlement, the conventional analysis method above-mentioned will violate much in contrast to actual engineering state.When differential settlement of foundation soil influences upper structure through foundation, maybe the construction or building maybe will tilt, sub-stress will take place in the upper structure, then structural components and non-structural components will crack and even be destroyed. The general responses of different construction cases may differ from each other because of their different upper structure forms or different foundation forms.In this passage, referring to traditional settlement calculating method in civil engineering codes, the author analysed the differential settlement of the foundation under a certain construction's raft foundation with Graphic Computation Method and engineering analytic software ANSYS. The author also basically discussed the tilting response trend of the raft foundation in case of differential settlement of the construction's foundation, analysed the intrinsic cause and extrinsic cause of the differential settlement of the construction, then put forward some advices for the future engineering design.