岩石卸荷的Mogi-Coulomb强度准则适用性研究

RESEARCH ON THE APPLICABILITY OF MOGI-COULOMB STRENGTH CRITERION FOR ROCK UNLOADING

  • 摘要: 大量工程实践表明:岩石在卸荷条件下的强度特性与加载条件下相比,存在本质上的不同。结合岩石卸荷的破坏特征和强度特性,建立了岩桥贯通力计算模型,并基于应力强度因子叠加减原理,推导了岩石卸荷条件下的岩桥贯通力计算公式,从而探究Mogi-Coulomb强度准则对于岩石卸荷强度的适用性。将岩桥贯通力作为表征岩石卸荷破坏的强度参数,并与Mogi-Coulomb强度准则的核心参数——八面体剪应力进行对比,发现二者的量值具有极高相似性,这一发现可以间接证明Mogi-Coulomb强度准则适用于岩石卸荷强度方面的相关研究。本文揭示了岩石卸荷破坏时其岩桥贯通与八面体剪应力之间存在的紧密联系,可为岩石卸荷破坏的研究提供借鉴与参考。

     

    Abstract: A large number of engineering practices show that the strength characteristics of rock under unloading conditions are essentially different from those under loading conditions. Combined with the failure characteristics and strength characteristics of rock unloading, the calculation model of rock bridge penetration force is established. Based on the principle of superposition and reduction of stress intensity factor, the calculation formula of rock bridge penetration force under rock unloading condition is derived to explore the applicability of Mogi-Coulomb strength criterion to rock unloading strength. Furthermore, the rock bridge penetration force is used as the strength parameter to characterize the unloading failure of rock, and compared with the core parameter of Mogi-Coulomb strength criterion-octahedral shear stress. It is found that the magnitudes of the two are very similar. This finding can indirectly prove that the Mogi-Coulomb strength criterion is suitable for related research on rock unloading strength. Relevant research reveals the close relationship between rock bridge penetration and octahedral shear stress during rock unloading failure, which can provide reference for the study of rock unloading failure.

     

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