断裂岩石蠕剪中的细观接触损伤试验研究  

Experimental study of the meso-contact damage of fractured rocks in creep shear

作　　者：王金安[1] 李飞[1] 曹秋菊[1] 鞠杨[2] 毛灵涛[2] 

机构地区：[1]北京科技大学土木与环境工程学院,金属矿山安全高效开采教育部重点实验室,北京100083 [2]中国矿业大学煤炭资源与安全开采国家重点实验室,北京100083

出　　处：《岩土力学》2013年第12期3345-3352,3383,共9页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973项目)(No.2010CB731500);国家自然科学基金项目(No.41172264)

摘　　要：为深刻理解构成断裂岩体长期抗剪强度的细观机制,对岩石断裂面的细观接触和损伤演化进行了试验研究。采用压剪方式和巴西劈裂方式制作出两类断裂岩石,在恒定法向力作用下对破坏岩石试件进行分级施加剪切力的蠕变试验。在加载前、中、后对断裂岩石分别进行CT和激光扫描,观察到不同蠕变阶段断裂岩石的细观接触和损伤状态,获得不同性质的断裂岩石抗剪强度特征。试验研究表明:构成断裂岩石长期抗剪强度的机制主要有两个:一是细观凹凸啮合体的抗剪断能力;二是表观凹凸接触体的抗摩擦能力。拉破裂岩石表面局部粗糙度相对较大,抗剪强度以第1种破坏机制为主,剪切破坏岩石表面宏观起伏度较大,抗剪强度是以第2种破坏机制为主。在蠕变剪切过程中,两种机制交织在一起,并随时间或剪位移的增加而相互转换。To make a better understanding of the meso-mechanism of composing the long-term shear strength of fractured rocks, an experimental study of the micro-contact and damage evolution of fracture sfirfaces in rocks is carried out. Two types of fractured rocks are made by compressive shear and Brazilian tests respectively. Under a constant normal load, the fractured rock samples are tested by stepwise increasing creep shear forces. The fractured rocks are scanned using CT and laser scanner before, in the middle and after the creep shear test respectively. The meso-contact and the damage states in the fractured rocks are observed in different loading stages; and then the shear strength of the fractured rocks are obtained. The experimental results show that the long-term shear strength of fractured rocks is composed mainly by two mechanisms, one is the anti-shear ability of interlocked meso-asperities; the other is the anti-friction ability of contacted asperities. The tensile fractured rocks preset a relatively higher roughness and the shear strength is mainly from the first mechanism. The shear fractured rock gives rise to a relatively higher roughness; and the shear strength is mainly from the second mechanism. During creep shear, the two mechanisms are interacted and changed their roles with the development of time and shear displacement.

关 键 词：断裂岩石 细观接触 蠕变剪切 CT扫描 抗剪强度 

分 类 号：TU45[建筑科学—岩土工程]