黄慧琦, 杨更社, 叶万军, 等. 2022. 基于CT-CA的天然裂隙岩石受拉破坏特性研究[J]. 工程地质学报, 30(5): 1438-1449. doi: 10.13544/j.cnki.jeg.2022-0426.
    引用本文: 黄慧琦, 杨更社, 叶万军, 等. 2022. 基于CT-CA的天然裂隙岩石受拉破坏特性研究[J]. 工程地质学报, 30(5): 1438-1449. doi: 10.13544/j.cnki.jeg.2022-0426.
    Huang Huiqi, Yang Gengshe, Ye Wanjun, et al. 2022. Study on tensile failure characterisitcs of natural fractured rock based on CT-CA[J]. Journal of Engineering Geology, 30(5): 1438-1449. doi: 10.13544/j.cnki.jeg.2022-0426.
    Citation: Huang Huiqi, Yang Gengshe, Ye Wanjun, et al. 2022. Study on tensile failure characterisitcs of natural fractured rock based on CT-CA[J]. Journal of Engineering Geology, 30(5): 1438-1449. doi: 10.13544/j.cnki.jeg.2022-0426.

    基于CT-CA的天然裂隙岩石受拉破坏特性研究

    STUDY ON TENSILE FAILURE CHARACTERISITCS OF NATURAL FRACTURED ROCK BASED ON CT-CA

    • 摘要: 岩石内部存在的裂隙、孔洞等天然损伤对岩石的力学性能和破坏过程有重要影响,依据细胞自动机理论结合CT无损识别技术实现了含天然裂隙岩石在劈裂条件下裂纹扩展和贯通全过程及其力学性能变化规律的研究。从裂隙砂岩的真实细观结构出发,构建了天然裂隙岩石的数值计算模型,运用CASRock数值计算软件完成了含不同裂隙倾角的砂岩劈裂破坏的数值试验,分析了裂隙倾角对砂岩的力学特性、裂纹扩展过程及能量演化的影响规律。研究表明:(1)天然裂隙砂岩的抗拉强度与裂隙倾角密切相关,随着裂隙倾角的增加,其抗拉强度呈现先减小后增加的趋势;(2)裂隙起裂于天然裂隙尖端,当裂隙倾角0°≤θ<48°时,岩样的破坏是由错开型裂纹引起,裂纹沿着与天然裂隙近垂直方向扩展;当裂隙倾角48°≤θ<94°时,岩样的破坏是由张开型裂纹引起,裂纹沿着与天然裂隙近平行方向扩展;(3)劈裂过程中裂纹尖端应力场存在拉应力区和压应力区,拉应力造成翼裂纹由天然裂隙尖端沿加载端方向萌生扩展,而压应力则引发次生裂纹沿天然裂隙方向扩展;(4)含天然裂隙砂岩劈裂破坏过程能量演化可划分为4个阶段,随裂隙倾角的增大,峰值点处的总能量密度、弹性能密度先缓慢减少再迅速增加,但对岩样耗散能影响不大。

       

      Abstract: The natural damage such as cracks and holes in rock can have important impact on the mechanical properties and failure process of rock. Using the cellular automata theory and CT nondestructive identification technology,we study the whole process of crack propagation and coalescence and the change law of mechanical properties of rock containing natural cracks under splitting conditions. Based on the real micro-structure of fractured sandstone,we construct the numerical calculation model of natural fractured rock,complete the numerical test of sandstone splitting failure with different fracture dip angles,and analyze the influence of fracture dip angle on the mechanical properties,crack propagation process and energy evolution of sandstone. The results show that:(1)The tensile strength of fractured sandstone is closely related to the fracture dip angle. With the increase of fracture dip angle,the tensile strength decreases first and then increases. (2)The fracture starts at the tip of the initial fracture. When the dip angle is greater than 0° and less than 48°,the staggered crack causes the failure of the rock sample,and the main crack propagates along the vertical direction near the initial fracture; When the dip angle is greater than 48° and less than 94°,open crack causes the failure of rock sample,and the main crack propagates along the parallel direction with the initial crack. (3)There are tensile stress zone and compressive stress zone at the crack tip during the splitting process. The tensile stress causes the wing crack to initiate and propagate along the natural crack tip,while the compressive stress causes the secondary crack to propagate along the original crack direction. (4)We divide the energy evolution of the splitting failure process of sandstone with natural fractures into four stages. With the increase of fracture dip angle,the total energy density and elastic energy density at the peak point decrease slowly and then increase rapidly,but have little effect on the dissipation energy of rock samples.

       

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