通过对直剪试件剪切面内应力集中系数分布规律的研究,结合剪应力–剪切位移变化曲线的分析,提出一种采用应力集中系数进行土体抗剪强度取值的方法。以武汉地铁六号线某区间段角砾黏土地层为研究对象,进行室内大型直剪试验,得出角砾黏土的抗剪强度参数随含石量的变化规律,与规程方法进行对比分析,探讨文中方法的可行性。结果表明,应力集中系数K0一定程度上能够反映直剪时土体剪切承载力的强弱;角砾黏土的黏聚力随着含石量的增加呈近似线性关系,与现有研究成果一致;试验结果位于规程规定合理范围内,说明基于应力集中系数的抗剪强度取值方法可作为研究土体强度特性的有效途径。 Through the study of the distribution law of stress concentration factor in the shear plane of the direct shear specimen and the analysis of the change curve of the shear stress and shear displacement, a method of using the stress concentration factor to calculate the shear strength of the soil was proposed. Take the large-scale direct shear test in a section of Wuhan Subway Line 6 for a certain period of time, the shear strength parameters of breccia clay are obtained with the variation of stone content and compared with the rules and methods The feasibility of the method in this paper. The results show that the stress concentration coefficient K0 can reflect the strength of shear strength of soil under direct shear to some extent. The cohesion of breccia clay shows an approximately linear relationship with the increase of rock content, which is in agreement with the existing research results . The test results are within the reasonable range stipulated in the rules, which shows that the method of determining shear strength based on stress concentration factor can be used as an effective way to study the strength characteristics of soil.