考虑桩-土相互作用的深厚软土桩侧极限抗力分析

Analysis on ultimate resistance of deep soft soil pile side considering pile-soil interaction

为正确描述深厚软土层中桩-土相互作用,求解桩侧极限抗力,采用有限差分法对软土中不同桩径、不同深度的桩-土相互作用进行研究,基于Soft-Soil本构模型对桩周土体的受力变形、桩侧极限土抗力进行探讨分析,并对软土模量、强度参数以及p-y曲线等经验公式在深厚软土层中的应用进行了修正优化。研究表明:1)桩体承受的横向荷载水平对桩周土抗力分布影响大,在横向荷载作用下桩周土抗力呈椭圆分布;2)修正后的公式能够较好地描述软土层中桩-土相互作用关系;3)当软土地层较深(大于25 m)时,数值计算结果与修正后的公式计算结果较吻合。本文成果可为深厚软土层中的桩基设计提供参考。

In order to correctly describe the pile-soil interaction in deep soft soil and solve the ultimate resistance of the pile side,the pile-soil interaction of different pile diameters and depths in soft soil are studied by using the finite difference method.Based on the Soft-Soil constitutive model,the stress and deformation of the soil around the pile and the ultimate soil resistance of the pile side are discussed and analyzed,and the application of empirical formulas such as soft soil modulus,strength parameters and p-y curve in deep soft soil layers is modified and optimized.The research shows that:1)the lateral load level of the pile has a great influence on the distribution of soil resistance around the pile.Under the action of lateral load,the soil resistance around the pile is distributed in an elliptical manner;2)The revised formula can better describe the pile-soil interaction in soft soil layers;3)When the soft soil layer is deep(greater than 25 m),the numerical calculation results are consistent with the calculation results of the modified formula.The results can provide some reference for the design of pile foundation in deep soft soil layers.