摘要
地下洞室围岩开挖卸荷常发生张拉、剪切等破坏模式。为研究不同破坏模式对岩石破裂面形貌特征的影响,基于黑砂岩直接拉伸与拉伸剪切试验,通过引入二维、三维粗糙度评价指标,定量表征岩石破裂面的形貌特征,获得了拉应力作用下岩石破裂面粗糙度随应力状态的变化规律,简要探讨了不同破裂机制对破裂面形貌影响。研究发现各类粗糙度评价指标均随拉应力的增大而呈线性减小趋势。同时,基于各向异性特征参数K_a的度量,相比二维粗糙度评价指标θ_(max)/(C+1)_(2D),三维评价指标θ_(max)/(C+1)_(3D)更能准确表征岩石破裂面的粗糙特性,其与拉应力之间呈指数型变化关系。对于直接拉伸试验,岩石破裂面形貌差异最小;而对于拉伸剪切试验,随着拉应力的减小,破裂面各向异性程度逐渐增大。研究结果表明不同的岩石破坏模式和破裂机制是造成破裂面形貌特征具有差异性的根本原因。
Excavation and unloading from surrounding rock of underground caverns often cause failure modes such as tension and shear.In order to study the influence of different failure modes on the morphological characteristics of rock fracture surface,the direct tensile test and tension-shear test of black sandstone are carried out,and the two-dimensional and three-dimensional evaluation index are introduced to quantitatively characterize the rock fracture surface.The morphological characteristics of the rock fracture surface under the tensile stress are obtained,and the effects of different rupture mechanisms on the morphological characteristics of the fracture surface are briefly discussed.It is found that all kinds of roughness evaluation indexes decrease linearly with the increase in tensile stress.At the same time,based on the measurement of the anisotropic characteristic parameter Ka,the three-dimensional roughness evaluation indexθmax/(C+1)3D can accurately characterize the roughness of the rock fracture surface compared with the two-dimensional indexθmax/(C+1)2D,and it has an exponential relationship to the tensile stress.For the direct tensile test,the difference in the morphology of the rock fracture surface is the smallest;for the tension-shear test,the degree of anisotropy of the fracture surface gradually increases to the decrease of the tensile stress.The results show that different rock failure modes and rupture mechanisms are the root causes of the differences in the morphology of the fracture surface.
作者
陈珺
周辉
侯靖
卢景景
张传庆
崔国建
倪绍虎
CHEN Jun;ZHOU Hui;HOU Jing;LU Jingjing;ZHANG Chuanqing;CUI Guojian;NI Shaohu(PowerChina Huadong Engineering Corporation Limited,Hangzhou,Zhejiang 310014,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第S01期2623-2633,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金雅砻江联合研究基金重点项目(U1865203)
国家自然科学基金资助项目(51709257,51409265)。
