海洋软黏土大直径沉桩贯入挤土效应

Squeezing Effect of Pile Installation in Marine Soft Clay

【目的】研究海上沉桩贯入软土地基诱发的挤土效应。【方法】利用有限元大变形RITSS程序,通过大量的参数分析,对海洋地基桩基础贯入引起的挤土效应、土体破坏机理、周围土体的水平和隆起位移,以及挤土效应的影响范围展开系统研究。【结果】将数值模型与锥形桩(圆锥贯入仪)经典理论解进行比对,获得了较好的一致性。对大量数值仿真结果进行统计,获得在海洋地基中沉桩时土体的径向位移和垂直隆起高度的定量化描述,桩周土在1~3倍圆桩半径范围内最大水平位移为0.26R。【结论】提出关于水平位移和隆起高度的计算公式,能够预测沉桩对临近土体扰动的影响范围,能较为准确地评估多桩系统中沉桩对临近桩基础的影响。

【Objective】To study the compaction effect of pile installing in soft soil.【Method】The large deformation finite element large deformation(LDFE)program(RITSS)was employed to study the soil compaction effect caused by the penetration of pile foundation into the marine soft clay.A systematic parametric study was then carried out considering the penetration depth and soil profile.This study also quantify its effect on horizontal displacement of soil around pile,vertical displacement of the surrounding soil,and the influence range of the compaction effect.【Result】The numerical model was validated against classical theoretical solutions for a degenerated conical shape pile(cone penetrometer),with good agreement obtained.Based on the LDFE results,it is found that the maximum horizontal deformation of soil round pile within 1R to 3R can reach 0.26R,and the quantitative description of the radial displacement and surface heave of soil were obtained.【Conclusion】Two formulas for predicting the lateral displacement and the soil heave have been proposed,which can estimate the influence of pile installation on the soil defamation in the disturbance zone,and provide a guidance for engineers to estimate the pile penetration influencing on adjacent pile foundation.