人工冻黏土单轴无侧限抗压强度试验研究

    Uniaxial Compressive Strength Test on Artificially Frozen Clay

    • 摘要: 对祁南矿井3个不同层位的原状冻土样及同含水率下的重塑冻土样进行单轴无侧限抗压强度试验。试验分析表明:原状冻土试样破坏时均发生沿斜向下45°~ 55°方向的剪切破坏,而重塑冻土试样破坏时表面产生网状裂纹,呈塑性破坏;试验过程中原状冻土和重塑冻土试样的应力-应变曲线均呈现出软化现象,采用改进后的软化模型能够较好拟合试验曲线的发展趋势;同一土样在相同含水率下,负温对重塑土抗压强度的影响程度大于原状土,且负温越大,影响程度越大,当负温达到一定值后,重塑冻土的抗压强度接近原状冻土的抗压强度;试验建立了以温度为变量的指数函数强度模型以及幂函数峰值强度比模型。

       

      Abstract: Uniaxial unconfined compressive strength test of the original frozen soil sample and its remodeled frozen soil sample of 3 different layers of Qinan Mine was carried out. The analysis of experimental results show that shear destruction occurred along the slope downward 45 to 55 degrees when the original permafrost sample was destroyed. While the destruction of permafrost samples is the brittle destruction of surface mesh cracks; the stress-strain curves of the original permafrost specimen and the reshaping permafrost specimen are both softened during the test process, the improved softening model can be better to simulate the trend of the test curve; the effect of negative temperature on the strength of reshaping soil is greater than the original soil, and the greater of negative temperature value, the greater of the impaction, when the negative temperature value is larger, the strength of remodeling permafrost is close to the strength of original permafrost; the index function strength model and the peak strength ratio model of power function with temperature were established.

       

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