基于土体变形的端承桩负摩阻力计算方法研究  

Calculation method of negative skin friction for end-bearing piles based on soil deformation

作　　者：周光远 干飞 郑刚[2] 周海祚[2] 王宏 毕靖 刘彪 张元胤 ZHOU Guang-yuan;GAN Fei;ZHENG Gang;ZHOU Hai-zuo;WANG Hong;BI Jing;LIU Biao;ZHANG Yuan-yin(School of Civil Engineering,Guizhou University,Guiyang,Guizhou 550025,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China;Guizhou Power Transmission and Transformer Company Limited,Guiyang,Guizhou 550000,China)

机构地区：[1]贵州大学土木工程学院,贵州贵阳550025 [2]天津大学建筑工程学院,天津300072 [3]贵州送变电有限责任公司,贵州贵阳550000

出　　处：《岩土力学》2025年第3期930-942,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52164001);贵州省科技支撑计划基金会(No.[2021]–general511)。

摘　　要：施加较大的附加荷载会引起桩周土体变形,从而产生一种向下的拖曳力,通常称为负摩阻力。这种现象显著降低了桩的极限轴向承载力。因此,精确计算负摩阻力对桩基设计至关重要。为准确计算作用于桩上的负摩阻力,确定桩-土界面在不同土体变形条件下的应力状态是至关重要的。然而,许多现有方法仅考虑剪切面上的峰值或残余应力,而忽略了土体变形的全过程应力状态。这种方法往往会高估负摩阻力。提出了一种新的负摩阻力计算方法,该方法考虑了土体变形过程中完整的应力状态变化(包括破坏前区及峰值应力、破坏后区及残余应力状态),利用双曲力学模型描述土体变形与应力之间的关系。在此基础上,将土体变形行为划分为3种不同的形式,并分别针对每种形式探讨了负摩阻力的空间分布特性。此外,还研究了不同土体参数对负摩阻力空间分布的影响。最后,通过与现场实测数据对比,验证了新负摩阻力计算方法的准确性和适用性,可为实际工程提供参考。The application of a significant additional load induces soil deformation around the pile,generating a downward drag force,commonly referred to as negative skin friction.This phenomenon significantly reduces the pile's ultimate axial load capacity.Therefore,precise estimation of negative skin friction is crucial for pile design.To accurately calculate the negative skin friction acting on the pile,it is essential to determine the stress states at the pile-soil interface under varying soil deformations.However,many existing methodologies solely consider peak or residual stresses on the shear plane,neglecting the process of stress changes in soil deformation.This approach often results in an overestimation of negative skin friction.In this investigation,we propose a novel method for calculating negative skin friction that comprehensively accounts for the whole process of stress state alterations occurring during soil deformation(pre-failure zone and peak stress,post-failure zone and residual stress state)and describes the relationship between soil deformation and stress using a hyperbolic mechanical model.On this basis,soil deformation behavior is classified into three distinct forms.The spatial distribution characteristics for negative skin friction were then explored individually for each form.Additionally,the influence of different soil parameters on the spatial distribution of negative skin friction was also investigated.Finally,the accuracy and applicability of the new negative skin friction calculation method is validated through comparison with field measurement data.It can be used as a reference for practical engineering.

关 键 词：土体变形 负摩阻力 桩基础 应力状态 双曲力学模型 

分 类 号：TU443[建筑科学—岩土工程]