非深厚软土地基下桩筏基础减沉桩的设计与应用

Design and application of settlement reducing pile in pile raft foundation on shallow soft soil ground

泰安某商业综合体项目筏板基础底落于粉质黏土层,经承载力修正后,地基承载力基本满足设计要求,但沉降过大,超出规范限值要求,对于这种情况,基础结构设计首先考虑了减沉桩方案。该项目减沉桩方案的特殊性在于要同时考虑抗压及抗浮工况下的桩设计和桩端落于强风化泥岩较硬土层时减沉桩的适用性。通过有限元方法模拟,分工况计算分析了桩和桩间土的承载力及沉降的变化情况,验证了各工况下以强风化泥岩层为持力层时,减沉桩筏基础沉降可以得到有效控制,且承载力等指标均能满足规范要求。

In a commercial complex project in Tai′an, the raft foundation bottom fell on the silty clay layer. After the bearing capacity correction, the bearing capacity of the foundation basically met the design requirements, but the settlement was too large and exceeded the specification requirements. For this case, the settlement reducing pile scheme was first considered in the foundation structural design. The particularity of the project was to consider the pile design under both compression and anti-floating conditions and the applicability of the pile when the pile end fell in the hard soil layer of strongly weathered mudstone. Through the finite element method simulation, the bearing capacity and settlement of the pile and the soil between the piles were calculated and analyzed according to the working conditions. It was verified that the settlement reducing pile raft foundation could be effectively controlled when the strongly weathered mudstone layer was taken as the bearing layer, and the bearing capacity and other indexes could meet the requirements of the specification.