基于剪切破坏面修正的地基极限承载力计算方法  

Calculation Method of the Ultimate Bearing Capacity of Foundation Based on Shear Failure Surface Correction

作　　者：史元祺 曹振中[2] 景立平[1] 莫红艳[2] Shi Yuanqi;Cao Zhenzhong;Jing Liping;Mo Hongyan(Key Laboratory of Earthquake Engineering and Engineering Vibration of China Earthquake Administration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,P.R China;Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin University of Technology,Guilin,Guangxi 541004,P.R.China)

机构地区：[1]中国地震局工程力学研究所中国地震局地震工程与工程振动重点实验室,哈尔滨150080 [2]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004

出　　处：《地下空间与工程学报》2025年第1期31-41,共11页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51968015)。

摘　　要：地基承载力计算是土力学的重要课题之一,由土体重度贡献的承载力系数Nγ仍缺少精确的理论解答。经典极限承载力公式的剪切破坏面均人为假定,实际剪切破坏特征可能与假设存在较大差异,尤其当内摩擦角大于35°时,摩擦角的变化对剪切破坏面深度、宽度范围的影响显著。本文提出等效替代思想,将土重引起的力矩等效为破坏面上抗剪强度分量的抗滑力矩,并从两者对承载力贡献的物理力学机制出发,分析了等效替代的合理性。在经典滑移线几何表达式中引入形状修正系数,提出了基于剪切破坏面修正的极限承载力公式,计算公式可根据实际的剪切破坏面形态进行调整,在一定程度上弥补了假定的剪切破坏面与实际不符的缺陷。将载荷试验、数值计算结果对极限承载力计算公式进行了检验,并与Terzaghi、Vesic等经典地基极限承载力公式进行了误差对比分析,表明本文公式具有较好的计算精度与适用性。The bearing capacity calculation foundation is one of the important topics in soil mechanics,and the bearing capacity coefficient contributed by the weight of the soil mass still has no accurate theoretical answer.The shear failure surface of the classical ultimate bearing capacity formula are artificially assumed,and the actual shear failure characteristics may differ greatly from the assumptions,especially when the internal friction angle is greater than 35°,the change of friction angle has a significant impact on the depth and width range of the shear failure surface.In this paper,the idea of equivalent substitution is proposed to equate the moment caused by soil weight to the slip resistance moment of the shear strength component on the damage surface for calculation,and the rationality of equivalent substitution is analyzed in terms of the physico-mechanical mechanism of the contribution of both to the bearing capacity.A shape correction factor is introduced into the classical slip line geometric expression,and an ultimate bearing capacity formula based on the shear damage surface correction is proposed.The calculation formula can be adjusted according to the actual shear damage surface morphology to make up for the deficiency that the assumed shear damage surface does not match with the actual one.The collected load test and numerical calculation results are examined for the ultimate bearing capacity formula proposed in this paper,and the error comparison analysis is carried out with the classical foundation ultimate bearing capacity formula developed by Terzaghi and Vesic,which shows that the formulae in this paper have good calculation accuracy and applicability.

关 键 词：极限承载力 承载力系数 条形基础 等效替代 破坏面修正 

分 类 号：TU470[建筑科学—结构工程]