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为研究冻土的应力应变关系以及冻土材料在荷载作用下的强弱变化,对冻结状态下的掺砂粉质黏土在不同围压(0.3 MPa、1.4 MPa和6.0 MPa)下进行三轴压缩试验。结果表明:冻结状态下的掺砂粉质黏土的应力应变曲线表现为应变软化;峰值强度随着围压的增大先增大、后减少。借鉴损伤力学的概念,引入了强化参数和弱化参数来描述材料的加强弱变化对三轴压缩试验的影响,再基于分数阶导数的理论提出了一个新的应力应变关系模型。最后,对模型参数进行了分析和对模型进行拟合计算,结果表明,该模型可以很好地描述整个加载过程。
In order to study the relationship between stress and strain of frozen soil and the change of strength of frozen soil under load, triaxial compression of frozen sandy soil under different confining pressure (0.3 MPa, 1.4 MPa and 6.0 MPa) test. The results show that the stress-strain curves of frozen sandy silty clay show strain softening. The peak intensity increases first and then decreases with the increase of confining pressure. By referring to the concept of damage mechanics, we introduce the strengthening parameter and the weakened parameter to describe the influence of the weakening of the material on the triaxial compression test. Based on the theory of fractional derivative, a new stress-strain relationship model is proposed. Finally, the model parameters are analyzed and the model is fitted and calculated. The results show that the model can describe the whole loading process well.