赵宁, 王炀, 郭长宝, 等. 2024. 怒江夏里段变质砂岩不同卸荷速率下破坏特性研究[J]. 工程地质学报, 32(3): 825-839. doi: 10.13544/j.cnki.jeg.2023-0424.
    引用本文: 赵宁, 王炀, 郭长宝, 等. 2024. 怒江夏里段变质砂岩不同卸荷速率下破坏特性研究[J]. 工程地质学报, 32(3): 825-839. doi: 10.13544/j.cnki.jeg.2023-0424.
    Zhao Ning, Wang Yang, Guo Changbao, et al. 2024. Study on damage characteristics of metamorphic sandstone in the Xiali section of Nu River under different unloading rates[J]. Journal of Engineering Geology, 32(3): 825-839. doi: 10.13544/j.cnki.jeg.2023-0424.
    Citation: Zhao Ning, Wang Yang, Guo Changbao, et al. 2024. Study on damage characteristics of metamorphic sandstone in the Xiali section of Nu River under different unloading rates[J]. Journal of Engineering Geology, 32(3): 825-839. doi: 10.13544/j.cnki.jeg.2023-0424.

    怒江夏里段变质砂岩不同卸荷速率下破坏特性研究

    STUDY ON DAMAGE CHARACTERISTICS OF METAMORPHIC SANDSTONE IN THE XIALI SECTION OF NU RIVER UNDER DIFFERENT UNLOADING RATES

    • 摘要: 隧道不同的开挖掘进速率对岩体的力学特性有明显的影响,本文选取怒江夏里段典型变质砂岩,开展了不同速率条件下的真三轴卸荷试验。试验采用应力-应变监测、声发射监测、数值模拟等手段,探究了不同卸荷速率下岩石的变形破坏模式与破坏特性。结果表明:卸荷速率越快,张拉裂纹数量增加,岩石的破坏模式越复杂,呈现张剪共生的形态特征。不同的卸荷速率下,能量具有相同的演化趋势,随着卸荷速率的增加,试样弹性应变能占比增加,耗散能占比降低,用于破坏的能量增加,试样破坏越严重。试样的声发射能量变化表明在卸荷阶段,高卸荷速率产生的损伤变形最小,能量损伤也越小,在破坏阶段损伤发生的时间提前,从而形成更加剧烈的破坏。数值模拟试验表明随着卸荷速率的增加,岩石由剪切破坏逐步向张剪破坏过渡,在高卸荷速率下岩石破坏更为剧烈,同时能量演化规律与室内试验一致。

       

      Abstract: The different excavation rates of tunnels have obvious effects on the mechanical properties of rock mass. This paper selects widely exposed metamorphic sandstone in the Nu River tectonic me'lange belt to carry out true triaxial unloading tests under different unloading rates. The tests use stress and strain monitoring,acoustic emission monitoring,numerical simulation,and other methods to explore the deformation and failure modes and characteristics of the rock under different unloading rates. The test results indicate that the increase in unloading rate causes the number of tension cracks to continue to increase and the failure mode of the rock to become more complex,with symbiotic morphological characteristics of tension cracks and shear cracks appearing. According to the law of energy evolution,as the unloading rate increases,the proportion of elastic strain energy of the rock mass increases,and the proportion of dissipated energy decreases. The energy used for rock mass destruction under peak stress increases,and the sample failure becomes more severe. The change in acoustic emission energy appears in the unloading stage. High unloading rates produce the smallest damage deformation and less energy damage. In the destruction stage,damage occurs earlier,resulting in more severe damage. Numerical simulation tests show that as the unloading rate increases,the rock mass gradually transitions from shear failure to tension failure,and the elastic strain energy and dissipation energy are consistent with the indoor test rules. The faster the unloading rate,the more complex the rock failure becomes.

       

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