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.

    UNIAXIAL COMPRESSION TEST FOR THREE STRESS THRESHOLDS OF SILICEOUS SILTSTONE

    • 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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