Balanced Settlement Optimum Design Method Of Composite Pile Foundation

For the pile foundation on the soft soil, settlement control is the design key. The general design requires that loads are born entirely by piles, regretting the bearing capacity of soil between the piles. Based on the former researches, the Balanced Settlement Optimum Design Method is presented in this paper. According to this method, the differential settlement can be better reduced by adjusting the rigidity of both the foundation soil and the piles. Meanwhile, the average settlement and the whole bearing capacity all satisfy the code request, and the cost of foundation can also be reduced. The main contents are as the followings:â‘ The finite-element method is adopted in this paper to analyze the influence factors to the settlement of single pile, which are pile length, pile diameter,soil elastic modulus, cap width, cushion thickness and cushion elastic modulus etc. Especially, the whole course of the non-linear interaction on pile foundation-soil is simulated and some useful conclusions are given to be the reference of the pile group analysis.â‘¡The numerical simulation are carried through to analyze the composite pile foundation under the circular raft. By adjusting several main factors such as pile length, pile space and soil elastic modulus in the finite-element model, a conclusion can be drew that pile length adjusted method and central locating piles combining with soil elastic modulus modulation method are two most effective ways to reduce the differential settlement of composite pile foundation. Beside, this analysis process also gives out the common non-linear design method of pile-raft foundation which aims to reduce the differential settlement to zero.â‘¢Meanwhile, the distributions of additional stress of the composite pile foundation with equal pile length and the composite pile foundation with the adjusted soil rigidity. The research shows that: the additional stress distributions of the composite pile foundation with the adjusted soil rigidity cannot be easily predigested to be a trapezoid as the composite pile foundation with equal pile length because of the different pile disposal. Thus, it needs some more discussion.â‘£Combining with the actual settlement data of pile raft foundation from one oil storage tank, its pile length variation design is simulated by finite-element method. Beside, the finite-element model of central locating piles combining with soil elastic modulus modulation...