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为研究温度对粉质粘土变形特性的影响,以冻结粉质粘土为研究对象,通过三轴剪切试验,研究了不同温度条件下粉质粘土变形特性。试验结果表明:温度对土体的变形和强度存在显著影响。同一偏应力作用下,温度越低,变形越小。温度与冻结粉质粘土强度大致呈反余切函数关系。冻结粉质粘土应力-应变关系呈硬化型,无峰值强度。未冻粉质粘土应力-应变关系呈软化型,有峰值强度。依据Duncan-Chang模型建模思路建立了以温度为影响因子的冻结粉质粘土本构模型。偏应力和应变呈幂次函数关系。温度则主要通过幂次函数的系数A和B影响冻结粉质粘土的应变。最后,将建立的本构模型导入有限元分析软件MIDAS中,并以沈阳地铁DK11+395联络通道处工程为例,对冻结法施工过程中的土体变形进行了数值模拟。数值计算结果与现场监测结果吻合程度较好,验证了所建立本构关系模型的有效性。
In order to study the influence of temperature on the deformation characteristics of silty clay, the frozen silty clay was taken as the research object. The deformation characteristics of silty clay under different temperature conditions were studied by triaxial shear test. The experimental results show that temperature has a significant effect on the deformation and strength of soil. The same partial stress, the lower the temperature, the smaller the deformation. The temperature and the frozen silty clay have roughly inverse cotanteric functions. The stress-strain relationship of frozen silty clay is hardened and has no peak strength. The unfrozen silty clay has a softening and stress-strain relationship with peak strength. Based on the Duncan-Chang model modeling idea, a constitutive model of frozen silty clay with temperature as influencing factor was established. Deviation of stress and strain is a power function. The temperature affects the strain of the frozen silty clay mainly through the coefficients A and B of the power function. Finally, the constitutive model was imported into the finite element analysis software MIDAS, and the deformation of the soil was numerically simulated with the engineering of DK11 + 395 in Shenyang Metro as an example. The numerical results are in good agreement with the on-site monitoring results, which verify the validity of the constitutive model established.