A Semi-analytical Method for the Settlement Calculation of the Foundation-composite Ground Interaction

摘要

A Semi-analytical element method, used to calculate the settlement of composite foundation, has been presented in which the settlements are modeled by analytic functions in two horizontal directions and polynomial expressions in vertical direction. It can simplify 3-dimensional computation of displacement to one dimension, saving computation time dramatically for its quick convergence. Furthermore it can simulate infinite soil field, avoiding introduce redundant boundary condition compared with FEM, and acquires precise results. Some cases are calculated by changing foundation rigidity, substitution ratio, reinforced depth and modulus ratio of pile to soil. Foundation rigidity has great effect on the composite ground's settlement. With the increment of substitution ratio, the settlement decreases, so for the regular trigonal layout, piles spacing S_e= (3～4) d is more appropriate to reduce settlement. With the increment of modulus ratio of pile to soil, the deformation of underlying stratum increases. Compression deformation of composite soil mass can be ignored at the case of E_p/E_t ≥ 500. The settlement is reduced apparently with the pile length increasing, so it is economic to increase reinforcement depth to control the settlement comparing with substitution ratio.