This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength (PSS) of rock joints. Firstly, the contribution of the asperities with different apparent dip angles to shear strength is studied. Then the shear strength of the entire joint asperities is derived. The results showed that the PSS of the entire joint asperities is proportional to a key parameter θ_τ, which is related to the geometric character of the joint surface and the joint material properties. The parameter θ_τ is taken as the new roughness parameter, and it is reasonable to associate the PSS with the geometric characteristics of the joint surface. Based on the new roughness parameter and shear test results of 20 sets of joint specimens, a new PSS model for rock joints is proposed. The new model is validated with the artificial joints in this paper and real rock joints in published studies. Results showed that it is suitable for different types of rock joints except for gneiss joints. The new model has the form of the Mohr-Coulomb model, which can directly reflect the relationship between the 3D roughness parameters and the peak dilation angle.

这项研究旨在提出一个合理的粗糙度参数，以反映岩石节理的峰值抗剪强度（PSS）。首先，研究了不同表观倾角的凹凸对剪切强度的影响。然后得出整个关节粗糙的剪切强度。结果表明，整个关节凹凸的PSS是正比于关键参数θ _τ，这是关系到接头表面的几何特征和所述接合材料的性质。参数θ _τ作为新的粗糙度参数，将PSS与接合面的几何特征相关联是合理的。根据新的粗糙度参数和20组节理试样的剪切试验结果，提出了一种新的岩石节理PSS模型。本文中的人工节理和已发表的研究中的真实岩石节理验证了新模型的正确性。结果表明，除了片麻岩缝以外，它还适用于不同类型的岩石缝。新模型具有Mohr-Coulomb模型的形式，可以直接反映3D粗糙度参数和峰膨胀角之间的关系。