Abstract The applicability of the classic Terzaghi or Biot effective stress laws to fractured rocks is not clear. Based on discrete element models, bulk modulus method and equivalent strain method are presented to determine the effective stress coefficient of saturated fractured rocks, and were examined with the regular fracture network I. Two types of discrete fracture networks, including regular and random network models, were built, and a total of over 300 numerical simulations were performed using the equivalent strain method for sensitivity analysis of the effective stress coefficient of fractured rocks to the fracture geometries characteristics, and the mechanical properties of both the intact rock and the fracture. The classic effective stress laws for porous media cannot be extended to fractured rocks, mainly due to the different volumetric deformation behaviors between porous and fractured materials. The effective stress coefficient is the largest in the regular fracture network I and the smallest in the random fracture network. As the normal and shear stiffness of the fracture increase, the effective stress coefficient decreases, while it increases with the increasing elastic modulus and Poisson’s ratio of the intact rock. An empirical model was proposed to predict the effective stress coefficient of saturated fractured rocks.

中文翻译：

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饱和裂隙岩有效应力系数的研究

摘要 经典的 Terzaghi 或 Biot 有效应力定律对裂隙岩石的适用性尚不清楚。基于离散元模型，提出体积模量法和等效应变法来确定饱和裂缝岩的有效应力系数，并用规则裂缝网络I进行检验。 两种类型的离散裂缝网络，包括规则网络模型和随机网络模型，通过等效应变法对裂隙岩石有效应力系数对裂隙几何特征、完整岩石和裂隙力学性质的敏感性分析，共进行了300多次数值模拟。多孔介质的经典有效应力定律不能推广到裂隙岩石，主要是由于多孔材料和断裂材料之间的体积变形行为不同。有效应力系数在规则裂缝网络Ⅰ中最大，在随机裂缝网络中最小。随着裂缝法向刚度和剪切刚度的增加，有效应力系数减小，而随着完整岩石弹性模量和泊松比的增加，有效应力系数增加。提出了预测饱和裂隙岩有效应力系数的经验模型。随完整岩石弹性模量和泊松比的增加而增加。提出了预测饱和裂隙岩有效应力系数的经验模型。随完整岩石弹性模量和泊松比的增加而增加。提出了预测饱和裂隙岩有效应力系数的经验模型。