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为研究冻结粉质粘土强度和变形特性,以沈阳地铁DK11+395联络通道处人工冻结粉质粘土为研究对象,通过冻土三轴剪切试验,研究了不同试验条件下冻结粉质粘土的强度和变形特性.试验结果表明:围压、温度和试件初始含水量是影响冻结粉质粘土强度和变形的主要因素.冻结粉质粘土偏应力-应变曲线呈应变硬化型,其破坏强度和切线弹性模量随围压和试件初始含水量的增加而增大,随温度的升高而减小,破坏偏应力比Rf取值在0.79~0.96之间.基于试验数据建立了以上述三因素为影响因子的冻结粉质粘土Duncan-Chang模型.通过回归分析,建立了模型参数a和b与围压、初始含水量和温度之间的线性回归公式.将依据模型计算的偏应力-应变曲线与对比试验曲线相比较,发现两者具有较好的吻合程度,说明建立的模型能够准确反映围压、初始含水量和温度等条件对冻结粉质粘土强度和变形的影响规律.上述研究成果为冻结粉质粘土强度和变形特性的研究提供了参考,为人工冻结法施工提供了指导,具有重要的理论意义和工程应用价值.
In order to study the strength and deformation characteristics of frozen silty clay, artificial frozen silty clay in Shenyang Metro DK11 + 395 was used as the research object. Through the triaxial shear test of frozen soil, the strength of frozen silty clay under different experimental conditions And deformation characteristics of the frozen silty clay.The results show that the confining pressure, temperature and the initial moisture content of the sample are the main factors affecting the strength and deformation of the frozen silty clay.The deviatoric stress-strain curve of the frozen silty clay is in the strain hardening state, the failure strength and the tangent The elastic modulus increases with the increase of the confining pressure and the initial water content of the specimen, decreases with the increase of the temperature, and the value of the damage partial stress ratio Rf is between 0.79 and 0.96.According to the experimental data, As the influencing factor of frozen silty clay Duncan-Chang model.Using regression analysis, a linear regression formula between model parameters a and b and confining pressure, initial water content and temperature was established.The deviatoric stress-strain curve Compared with the comparative test curve, it is found that the two models have good agreement, indicating that the established model can accurately reflect the confining pressure, the initial water content and temperature conditions on frozen silty clay And the influence of deformation of the above findings provide for the study of frozen silty clay strength and deformation characteristics of the reference, provide guidance for artificial freezing method has important theoretical significance and application value.