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姚玮, 俞缙, 周先齐, 常方强, 常旭. 循环加载与卸围压组合扰动下红砂岩损伤破裂与渗透特性[J]. 岩土工程学报. DOI: 10.11779/CJGE20240053
引用本文: 姚玮, 俞缙, 周先齐, 常方强, 常旭. 循环加载与卸围压组合扰动下红砂岩损伤破裂与渗透特性[J]. 岩土工程学报. DOI: 10.11779/CJGE20240053
Red sandstone damage fracture and permeability characteristics under combined disturbance of cyclic loading and confining pressure unloading[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240053
Citation: Red sandstone damage fracture and permeability characteristics under combined disturbance of cyclic loading and confining pressure unloading[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20240053

循环加载与卸围压组合扰动下红砂岩损伤破裂与渗透特性

Red sandstone damage fracture and permeability characteristics under combined disturbance of cyclic loading and confining pressure unloading

  • 摘要: 为探究深地工程开挖诱导岩体损伤破裂及渗透性演化规律,开展了同步测定波速与渗透率的循环加载与卸围压组合扰动三轴试验,研究了不同条件下红砂岩的损伤与渗透性演化规律。结果表明:(1)岩石在不同组合扰动阶段具有不同的应力应变曲线形态,其末端形态取决于在何种扰动阶段破坏,初始应力比为决定组合扰动诱发岩石破坏难易的主要因素;(2)总峰值轴向应变随初始应力比增大而增大,其中组合扰动轴向应变占比始终较低,总峰值体积应变绝对值随初始应力比增大而先增大后减小,其中组合扰动体积应变占比较高;(3)在初始加载阶段,波速增大,渗透率降低,在组合扰动阶段,波速下降,渗透率增加,且损伤与体积应变近似呈线性关系,损伤与渗透率随扰动次数增加均呈先慢后快的增长趋势,且拐点分别近似在一条直线上;(4)岩石在组合扰动卸围压阶段破坏为单剪切破坏模式,在组合扰动循环加载阶段破坏为共轭剪切破坏模式;(5)双高(高初始应力比与高初始围压)条件将显著加剧岩体开挖失稳破坏风险。

     

    Abstract: To explore the rules of rock mass damage and permeability evolution induced by deep engineering excavation, cyclic loading and confining pressure unloading combined disturbance triaxial tests with simultaneous measurement of wave velocity and permeability were conducted. The damage and permeability evolution rules of red sandstone under different conditions were studied. The results showed that: (1) The rock exhibits different stress-strain curve shapes at different stages of combined disturbance, and their end shapes depend on which stage of disturbance the rock is failure. Initial stress ratio is the main factor to determine the difficulty of rock failure induced by combined disturbance. (2) The total peak axial strain increases with the increase of initial stress ratio, and the proportion of combined disturbance axial strain is always low. The absolute value of total peak volume strain increases first and then decreases with the increase of initial stress ratio, and the proportion of combined disturbance volume strain is high. (3) In the initial loading stage, the wave velocity increases and the permeability decreases. In the combined disturbance stage, the wave velocity decreases and the permeability increases. The damage and volume strain are approximately linearly related, and both the damage and permeability show a slow and then fast growth trend with the increase of disturbance times, and the inflection point seems to be on a straight line. (4) The rock exhibits a single shear failure mode during the combined disturbance unloading confining pressure stage, and a conjugate shear failure mode during the combined disturbance cyclic loading stage. (5) The double-high condition (high initial stress ratio and high initial confining pressure) will significantly increase the risk of rock excavation instability and failure.

     

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