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采用K0固结、负荷冻结、三轴压缩的试验方法,首次进行了4种不同温度梯度冻结中砂在加轴压(CTC)及减围压(RTC)两种路径下的三轴试验,获得了温度梯度和应力路径对冻结中砂应力–应变特性的影响。不同温度梯度及减围压试验的偏应力比–轴向应变关系曲线形态与传统均匀温度下冻结中砂加轴压试验结果类似,可用温度梯度的线性函数对双曲线模型进行修正后予以描述。但是不同温度梯度和两种应力路径条件下的应力应变特性存在很大差异,温度梯度状态和减围压应力路径对冻结中砂的应力–应变特性具有明显的“弱化效应”;温度梯度诱导了冻结中砂的非均质性,减小了模型的起始斜率,大大减低了抗变形能力;与加轴压应力路径相比,减围压应力路径试验的偏应力比大为降低,减围压应力路径(开挖过程)弱化了冻结中砂的强度。
Triaxial tests were carried out for the first time in four different temperature gradient freezing methods under the conditions of CTC and RTC with K0 consolidation, load freeze and triaxial compression tests. Effect of Temperature Gradient and Stress Path on Stress - Strain Characteristics of Frozen Middle Sand. The deviatoric stress-axial strain curves under different temperature gradients and depressurization tests are similar to the experimental results of freezing and axial compression tests under the traditional uniform temperature. The hyperbolic model can be described by a linear function of the temperature gradient. However, there are great differences in the stress-strain characteristics under different temperature gradients and two stress path conditions. The temperature gradient and the stress-strain path under reducing stress have obvious “weakening effect” on the stress-strain characteristics of the frozen sand. The temperature gradient The heterogeneity of sand in the frozen soil is induced, the initial slope of the model is reduced and the anti-deformability is greatly reduced. Compared with the axial compressive stress path, the deviatoric stress ratio of the path under stress-relief test is greatly reduced, Shrinkage of the compressive stress path (excavation process) weakens the strength of the frozen sand.