The Comparative Study Of Different Analysis Methods For Consolidation Of Sand Well Foundation By Preloading

Preloading method to reinforce the soft soil foundation has many advantages,constr-uction craft is already quite mature.The study of the theory have also made more results.However,how to evaluate the foundation reinforcement effect and Accurate estimates soft foundation settlement has been the problem needed to be further solved in the theoretical analysis and engineering design.At present,we design the project using one-dimensional axisymmetric equivalent single well theory under the flexibility conditions usually in engineering,in the theoretical analysis we use two-dimension plane strain equivalent sand wall method and the three-dimension finite element analysis method.Because the soft soil have typical the plastic properties,and sand well foundation is3d the deformation actually,compare the results using different analysis methods with the measured value.and then explore a more effective sand well calculation method for accurate analysis sand well foundation deformation characteristics have important significance in theory and practice.The paper expounds the preloading treatment of soft soil foundation mechanism,sand well consolidation theory and plane strain sand wall equivalent principle, and then using ABAQUS software and combining with the practical project, considering the sand well as flexibility and plastic (the modified Cambridge constitutive model), it analysis the sand well foundation using one-dimensional,two-dimensional,three-dimensional finite element methods.This paper gets following main conclusion.1.Under the elastic condition of one-dimensional axisymmetric single well,whatever instantaneous loading or classification loading,finite element analysis results is very consistent with Hansbo solution;according to the average consolidation degree of equal principle,after sand well equivalent,sand wall FEM solution is very consistent with equivalent axisymmetric FEM solution, sand foundation equivalent conversion in sand well wall is reasonable.2.In the elastic-plastic conditions,one-dimensional axisymmetric single well and its corresponding equivalent single (sand) wall have different geometry condition, therefore, even if the other terms the same,both the consolidation deformation is also different. 3.In the elastic-plastic conditions,although consolidation deformation in different position of sand well foundation using two-dimensional plane strain equivalent method are not identical,but if two-dimensional plane strain equivalent method and one dimensional equivalent single(sand)wall have the same material properties and the lotus conditions, both of the consolidation deformation and engineer measured value are consistent,and in the same time the settlements of two methods in general not more than5cm.This shows,using two-dimensional plane strain equivalent method analysis sand well foundation consolidation deformation is feasible.4.In the elastic-plastic conditions,the foundation consolidation deformation using three-dimensional finite element method is consistent with measured value.But three dimensional analysis work and needed computer memory are far higher than two dimensional analysis,therefore,for the consolidation deformation of sand well foundation analysis by preloading,we suggest using the two dimensional plane strain equivalent method.