张晓平, 吕根根, 张旗, 等.2020.单轴压缩条件下硅质粉砂岩应力阈值研究[J].工程地质学报, 28(3):441-449.doi:10.13544/j.cnki.jeg. 2019-085.
    引用本文: 张晓平, 吕根根, 张旗, 等.2020.单轴压缩条件下硅质粉砂岩应力阈值研究[J].工程地质学报, 28(3):441-449.doi:10.13544/j.cnki.jeg. 2019-085.
    Zhang Xiaoping, Lü Gengen, Zhang Qi, et al.2020.Uniaxial compression test for three stress thresholds of siliceous siltstone[J].Journal of Engineering Geology, 28(3):441-449.doi: 10.13544/j.cnki.jeg.2019-085.
    Citation: Zhang Xiaoping, Lü Gengen, Zhang Qi, et al.2020.Uniaxial compression test for three stress thresholds of siliceous siltstone[J].Journal of Engineering Geology, 28(3):441-449.doi: 10.13544/j.cnki.jeg.2019-085.

    单轴压缩条件下硅质粉砂岩应力阈值研究

    UNIAXIAL COMPRESSION TEST FOR THREE STRESS THRESHOLDS OF SILICEOUS SILTSTONE

    • 摘要: 岩石裂纹闭合应力(σcc)、起裂应力(σci)及损伤应力(σcd)是岩石压缩变形破坏过程中的关键应力阈值,应力阈值的确定对分析岩石宏观力学特性及研究微观裂纹演化规律具有重要意义。本文研究了硅质粉砂岩在单轴压缩条件下应力阈值确定的方法。针对硅质粉砂岩的应力-应变曲线开展不同方法的计算分析,判定不同方法下应力阈值获取的可靠性,并采用一种优化方法获取硅质粉砂岩试样的应力阈值。结果表明,裂隙体积应变法获取闭合应力与起裂应力的求解精度易受泊松比的影响,移动点回归法易受主观因素的干扰,横向应变响应法能减小人为主观误差,但其求解方法未阐释物理意义;采用基于移动点回归技术的裂隙体积应变法减小了岩石泊松比选取对应力阈值获取的干扰,且计算结果物理意义相对明确。

       

      Abstract: Crack closure stress(σcc), crack initiation stress(σci) and crack damage stress(σcd) are the key stress thresholds in rock compression failure process. The determination of the stress thresholds is of great significance for the analysis of the macroscopic mechanical properties of rocks and the evolution of microscopic cracks. Based on strain measurement method, this paper examines the methods of determining stress threshold of siliceous siltstone under uniaxial compression. The stress and strain curves of siliceous siltstone were analyzed by different methods. It determines the reliability of stress thresholds obtained under different methods, and selects an optimized method to obtain the stress thresholds of siliceous siltstone samples. The results show that the accuracy of obtaining the crack closure stress and crack initiation stress by the crack volumetric strain method is easily affected by the Poisson's ratio. The moving point regression method is susceptible to subjective factors. The lateral strain response method can reduce the subjectivity of human beings, but the accuracy of the solution does not explain the physical meaning. The crack volumetric strain method based on the moving point regression technique mitigates the interference of the rock Poisson's ratio on the stress thresholds, and the physical meaning of the obtained results is relatively clear.

       

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