群桩沉降计算的荷载传递法

群桩基础的沉降计算是桩基工程设计不可忽视的关键问题之一。通过对群桩基础沉降性状的分析,以荷载传递法为基础,导得了各基桩桩侧摩阻力在桩周土中产生的位移场,进而在考虑各桩的存在引起位移的折减后将其迭加,导得了计入桩与桩之间相互作用的桩侧单位厚度土的等效刚度系数;并通过对Boussinesq解进行桩的入土深度修正,从而导得桩端土的等效刚度系数,并在此基础上建立一种基于荷载传递法的群桩沉降计算方法。通过与已有模型桩基试验比较,理论计算与实测沉降吻合较好。

SETTLEMENT CALCULATION OF PILE GROUPS BY LOAD TRANSFER METHOD

Settlement calculation is one of the key problems that can not be neglected in the design of pile foundations. Based on the shear deformation transfer method, the settlement characteristics of pile foundations is analyzed, and the displacement fields in the surrounding soil of each pile in the group caused by shaft resistance are obtained. The displacement fields are modified by considering the reduction effect caused by the existence of piles. Superimposing the displacement fields in the surrounding soil of each pile in the group, the equivalent stiffness coefficients of unit thickness of soil around each pile are developed, taking into account the interaction among the piles. The Boussinesq solution is modified to include the effect of different embedded depths and then used to derive the equivalent stiffness coefficients of the soil under the pile tips. A method to calculate the settlement of pile groups is then established based on the load transfer method. Settlement predicted by the present method agrees well with those measured from the model test of pile foundations.