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为研究冻融循环作用对青藏粉砂土力学性质的影响,对不同冻融循环次数、冻结温度、围压下的粉砂进行常规静三轴剪切试验,研究冻融循环后土体的应力–应变关系曲线、静强度、弹性模量、抗剪强度参数的变化规律。试验结果表明:粉砂土的力学性质受冻融循环次数的影响较大,且在经历7~9次冻融循环后达到最小值。冻结温度对粉砂力学性质的影响较弱,且无一定规律。基于显著性分析理论,研究冻融循环次数、冻结温度、围压以及各因素间的交互作用对粉砂力学性质影响的显著性大小。分析结果表明:围压和冻融循环次数对力学性质影响的显著性较强,而冻结温度的影响较弱。同时,围压与冻融循环次数、冻结温度与冻融循环次数之间的交互作用对于粉砂的力学性质的影响均比较显著。
In order to study the effect of freeze-thaw cycles on the mechanical properties of Qinghai-Xizang silt, conventional static triaxial shear tests were carried out on different times of freeze-thaw cycles, freezing temperature and confining pressure to study the stress of soil after freeze-thaw cycles - Variation of strain curve, static strength, elastic modulus and shear strength parameters. The experimental results show that the mechanical properties of silty sand are greatly affected by the number of freeze-thaw cycles, and reach the minimum after 7-9 freeze-thaw cycles. The effect of freezing temperature on the mechanical properties of silt is weak, and there is no certain law. Based on the theory of saliency analysis, the effects of the number of freeze-thaw cycles, freezing temperature, confining pressure and the interaction between various factors on the mechanical properties of silty sand were studied. The analysis results show that the influence of confining pressure and the number of freeze-thaw cycles on the mechanical properties is significant, while the influence of freezing temperature is weak. At the same time, the interaction between the confining pressure and the number of freeze-thaw cycles, the freezing temperature and the number of freeze-thaw cycles have significant effects on the mechanical properties of silt.