人工冻结斜井洛河组砂岩解冻后蠕变模型试验研究

    Experimental study on creep failure mechanism of artificially frozen sandstone of Luohe Formation after thawing

    • 摘要: 随着西部地区煤矿建设,多数斜井需穿越弱胶结富水洛河组砂岩地层,采用常规掘进方式存在巨大安全隐患,往往采用冻结法施工掘进;人工冻结解冻后富水洛河组砂岩具有显著的蠕变特性,对于斜井井筒的长期安全稳定影响明显;通过对不同冻结温度下解冻后洛河组砂岩进行单轴压缩蠕变力学试验,从而建立了更为简洁的砂岩非线性分数阶蠕变力学模型;构建了解冻后砂岩的分数阶蠕变力学模型,将试验数据与拟合曲线进行对比分析。结果表明:随着冻结温度的降低,解冻后洛河组砂岩的蠕变量增大,蠕变速率增大,非线性程度升高;非线性分数阶蠕变模型可以很好地模拟解冻后洛河组砂岩的蠕变过程,模型更为简单方便。

       

      Abstract: With the construction of coal mines in western China, most inclined shafts need to pass through the weakly cemented water-rich sandstone stratum of Luohe Formation, and there are huge safety risks in conventional tunneling, so the freezing tunneling method is often adopted. After artificial freezing and thawing, the water-rich sandstone of Luohe Formation has significant creep characteristics, which has obvious influence on long-term safety and stability of inclined shaft. Based on uniaxial compression creep mechanics tests of defrosted sandstone of Luohe Formation at different freezing temperatures, a more concise nonlinear fractional order creep mechanics model of sandstone was established; the fractional creep mechanical model of defrosted sandstone is constructed, and test data and fitting curves are analyzed through comparison. The results show that: with the decrease of freezing temperature, the creep variable, creep rate and nonlinearity of sandstone in Luohe Formation increase after thawing, and the nonlinear fractional creep model can well simulate the creep process of defrosted Luohe Formation sandstone, and the model is simple and convenient.

       

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