摘要:
裂隙对岩体动态力学特性的影响机制一直是岩石力学领域的一个重点与难点问题，而裂隙岩体动态损伤模型的建立则是解决这一问题的关键，因而备受关注。目前大多数的裂隙岩体动态损伤模型均是针对平直裂隙，而无法考虑裂隙粗糙度的影响，为此针对这一不足，首先基于前人提出的能够同时考虑裂隙几何参数、强度参数及变形参数的岩体宏观损伤变量计算模型，通过引入Barton建立的粗糙裂隙JRC-JCS抗剪强度模型，提出了能够同时考虑裂隙粗糙度的岩体宏观损伤变量计算模型。其次，将该计算模型引入到前人提出的考虑宏细观缺陷耦合的非贯通裂隙岩体单轴压缩动态损伤模型中，建立了能够同时考虑裂隙粗糙度的非贯通裂隙岩体单轴压缩动态损伤模型。最后，通过参数敏感性分析研究了裂隙粗糙度JRC、裂隙面基本摩擦角φb、裂隙长度2a对岩体动态力学特性的影响。以动态峰值强度为例，算例表明，当JRC由0分别增加到10和20时，岩体动态峰值强度由26.42MPa分别增加到27.28MPa和28.37MPa。当φb由0º分别增加到15º和30º时，岩体动态峰值强度由26.24MPa分别增加到27.28MPa和28.80MPa。当2a由1cm分别增加到2cm和3cm时，岩体动态峰值强度由31.37MPa分别降低至27.28MPa和23.90MPa。同时为了更精确地刻画裂隙面粗糙度的影响，将裂隙面分形维数引入到岩体动态损伤模型中，不但提高了模型计算精度，而且拓宽了其应用范围，更便于实际工程应用。
Abstract:
The influence mechanism the crack on the dynamic mechanical property of the rockmass is always an important and difficult problem in the field of rock mechanics. However, the establishment of the dynamic damage model for the fractured rockmass is the key to solve this problem, which has attracted much attention. At present, most of the dynamic damage models for the fractured rockmass are aimed at the flat cracks, which cannot take into account the influence of the crack roughness. To address this shortcoming, on basis of the calculation model for the rockmass macroscopic damage variable which can take into account the crack geometry parameter, strength parameter and deformation parameter, a calculation model for the rockmass macroscopic damage variable is proposed by introducing the JRC-JCS shear strength model for the rough crack established by Barton, which can consider the crack roughness. Secondly, the proposed calculation model is introduced into the uniaxial compressive dynamic damage model for the rock mass with the non-persistent crack, which both considers the coupling of the macroscopic and microscopic defects, and then a uniaxial compressive dynamic damage model for the rock mass with the non-persistent crack is established which can consider the crack roughness at the same time. Finally, the effect of crack roughness JRC and crack basic friction angle φb and crack length 2a on rockmass dynamic mechanical property is studied with the parametric sensitivity analysis. Taking the rockmass dynamic climax strength as an example, the calculation example shows that the rockmass dynamic climax strength increases from 26.42MPa to 27.28MPa and 28.37MPa with JRC increasing from 0 to 10 and 20 respectively. The rockmass dynamic climax strength increases from 26.42MPa to 27.28MPa and 28.80MPa with φb increasing from 0º to 15º and 30º respectively. The rockmass dynamic climax strength decreases from 31.37MPa to 27.28MPa and 23.90MPa with 2a increasing from 1cm to 2cm and 3cm respectively. At the same time, in order to describe the influence of the crack roughness more accurately, the crack fractal dimension is introduced into the dynamic damage model for the rock mass, which not only improves the calculation accuracy of the model, but also broadens its application range, which is more convenient for practical engineering application.
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