岩石结构面Grasselli二维粗糙度指标优化及其JRC估算  

Updating Grasselli's 2D morphology parameter for estimating JRC of rock joints

作　　者：洪陈杰 翁寒倩 王凯 黄曼 陶志刚[1] 杜时贵 HONG Chenjie;WENG Hanqian;WANG Kai;HUANG Man;TAO Zhigang;DU Shigui(State Key Laboratory for Tunnel Engineering,China University of Mining and Technology,Beijing 100083,China;School of Civil Engineering,Shaoxing University,Shaoxing 312000,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing 312000,China;School of Civil&Environmental Engineering and Geography Science,Ningbo University,Ningbo 315000,China)

机构地区：[1]中国矿业大学(北京)隧道工程灾变防控与智能建养全国重点实验室,北京100083 [2]绍兴文理学院土木工程学院,浙江绍兴312000 [3]浙江省岩石力学与地质灾害重点实验室,浙江绍兴312000 [4]宁波大学土木与地理环境工程学院,浙江宁波315000

出　　处：《岩土工程学报》2024年第6期1146-1154,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(42272333,42277147)。

摘　　要：采用只考虑迎剪侧表观倾角而忽略内部起伏角的Grasselli二维形貌参数θ_(G)来估算结构面粗糙度系数JRC仍有待改进。从θ_(G)的物理意义出发,发现爬坡区内部凸起高度对粗糙度的贡献可表示为其在总爬坡水平距离上的坡角,所有爬坡区提供的坡角之和定义为结构面内部起伏体粗糙贡献,将结构面迎剪侧表观平均倾角θ_(G)和爬坡区内部平均坡角θ_(H)叠加,提出岩石结构面粗糙度新指标θ_(C)。通过获取十条标准JRC剖面线的θ_(C),分析其与JRC之间的关系,建立基于θ_(C)的JRC估算式。计算不同采样间距和不同采样方向下的新指标θ_(C),结果显示θ_(C)具有分形特征且能够反映结构面形貌各向异性。进一步将JRC估算式应用于JRC-JCS模型,通过对比已有研究得到的试验结果以及不同抗剪强度模型的预测效果,验证基于新指标θ_(C)估算的JRC可以准确预测结构面峰值抗剪强度。最后,对二维指标θ_(C)进行三维拓展,提出三维粗糙度新指标(θ_(C))_(3D),并通过结构面形貌各向异性表征验证了其合理性。The Grasselli's 2D morphology parameter θ_(G) used to estimate the joint roughness coefficient(JRC) is questionable,because it only considers the apparent inclination of the shear side and ignores the internal undulation angle.From the physical meaning of θ_G,it is found that the contribution of internal bulge height in the climbing area to surface roughness can be expressed as the slope angle at the total climbing horizontal distance.The sum of the slope angles provided by all climbing areas is defined as the roughness of joint internal undulating.The apparent average inclination angle θ_(G) and the internal average slope angle θ_(H) are superimposed to propose a new roughness parameter θ_(C) for rock joints.The θ_(C) of ten standard JRC profiles is obtained,and its relationship to JRC is then analyzed to establish an estimation formula for JRC based on θ_C.The proposed parameter θ_(C) under different sampling intervals and different sampling directions is calculated.The results show that θ_(C) has fractal characteristics and can reflect the anisotropy of joint surface morphology.Further,the estimation formula for JRC is applied to the JRC-JCS model.By comparing the experimental results obtained from the existing researches and the predicted results under different shear strength models,it is verified that the estimated JRC based on θ_(C) can accurately predict the peak shear strength of joints.Finally,the new parameter θ_(C) is extended to 3D form,and a 3D roughness parameter(θ_C)_(3D) is proposed to capture the anisotropic characteristics of joint morphology.

关 键 词：岩石结构面 粗糙度 表观平均倾角 内部平均坡角 抗剪强度 

分 类 号：TU45[建筑科学—岩土工程]