Mindlin解均化应力法计算桩基沉降及工程应用

Pile foundation settlement calculation based on Mindlin homogenized stress and its engineering application

基于群桩Mindlin应力解附加应力场和群桩基础变形分布特征,考虑承台和上部结构刚度对沉降变形的均化效应,总结了Mindlin解均化应力分层总和法计算群桩基础沉降的具体步骤细则。针对计算中具体问题,诸如压缩层计算厚度、上部结构刚度贡献、变刚度调平设计中桩类型的多样性,结合特定侧阻分布概化模式不同长径比、不同桩距条件给出基桩均化附加应力计算简易方法。应用所提供的均化附加应力计算方法计算群桩沉降,通过工程实例验证,与Boussinesq实体深基础计算法和等效作用计算法比较,其沉降计算值与实测竣工沉降值较为接近。

Based on the stress field calculated by the Mindlin stress theory and the existing Mindlin homogenization stress summation method for calculating the pile group foundation settlement,the deformation behavior of the pile-group foundation as well as the homogenization effect of pile cap and the superstructure stiffness on the settlement deformation was considered,and the detailed steps of Mindlin solution homogenized additional stress layer summation method to calculate the settlement of pile group foundation was concluded. Many specific problems exist in the calculation,such as the compression layer calculation thickness,the rigidity contribution of superstructure,the pile type diversity of optimized design of pile foundation stiffness to reduce differential settlement.A simplified method for calculating the homogenization additional stress of pile is presented based on the specific shaft resistance distribution model,the ratio of length to diameter and the distance between piles.Compared with Boussinesq deep foundation calculation method and equivalent calculation method,the proposed method in this paper can provide better settlement calculation values close to the tested ones.