基于Grasselli模型的一个新的岩石节理三维粗糙度指标  

A new three-dimensional roughness metric based on Grasselli’s model

作　　者：陈曦[1,2] 曾亚武[1,2] CHEN Xi;ZENG Ya-wu(School of Civil Engineering,Wuhan University,Wuhan,Hubei 430071,China;Hubei Provincial Key Laboratory of Safety for Geotechnical and Structural Engineering,Wuhan University,Wuhan,Hubei 430071,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430071 [2]武汉大学岩土与结构工程安全湖北省重点实验室,湖北武汉430071

出　　处：《岩土力学》2021年第3期700-712,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41772308,No.41272342)。

摘　　要：岩石节理粗糙度是影响岩体剪切力学特性和渗流特性的关键因素。为了获得一个具有各向异性特征且能够反映节理剪切机制的三维粗糙度指标,采用三维激光扫描仪对4组砂岩节理开展了形貌扫描试验,结合Grasselli模型的思想,提出了一个新的三维粗糙度指标θ_(R)^(*)。为了验证新指标的合理性,将其与其他3种模型进行了对比,分析结果表明:相较于Grasselli模型、Liu模型以及Tian模型,新模型与形貌测试结果更加吻合。首次提出了迎剪侧视倾角密度函数的概念,并发现Liu模型实质上遵循Weibull分布。相较于Grasselli模型、Liu模型以及Tian模型的理论密度函数,新模型的密度函数与试验实测结果更加吻合,从而证明了新模型的合理性。新的粗糙度指标更为简单,仅考虑迎剪侧视倾角的作用,量纲和物理意义明确,且和节理的粗糙度呈正相关,试验结果也表明新指标能够较好的反映节理粗糙度的各向异性。The roughness of joint surface has a significant influence on the shear behavior and hydraulic behavior of rock mass.In order to acquire a three-dimensional roughness metric which can capture the anisotropic characteristics of rough surface and reflect the shear mechanism of rock joint,morphological scanning tests were performed on four groups of sandstone joints by using a three-dimensional laser scanner.Based on Grasselli’s roughness model,a new three-dimensional roughness metric was proposed.Comparisons between another three models(Grasselli’s model,Liu’s model and Tian’s model)and the new model show that the new model is more consistent with the test results.In addition,a new concept that characterizes the density of the apparent dip angle facing the shear direction is established in this study,and it is found that Liu’s model conforms to the Weibull distribution.Compared to the theoretical density function of Grasselli’s model,Liu’s model,and Tian’s model,the new model has a better agreement with the experimental data,which verifies the rationality of the new model.The new roughness metric is simple and clear physically since it only takes the apparent dip angle facing the shear direction into account.The new roughness metric is positively correlated with the roughness of joints.Furthermore,the anisotropy of surface roughness can also be well characterized by the new roughness metric.

关 键 词：岩石力学 节理 粗糙度指标 Grasselli模型 各向异性 

分 类 号：TU451[建筑科学—岩土工程]