摘要
断层破碎带颗粒介质体系中力链形成机制及其演化规律,是研究含破碎带断层蠕滑、黏滑以及地震等地质灾害发生的重要基础。借助颗粒体双轴加载双向流动光弹试验装置,对断层破碎带剪切作用下的宏观力学特性、破碎带中光弹力链网络结构及演化、力链空间分布及强度等特征进行研究。结果表明:(1)断层破碎带中,岩体颗粒之间通过力链传递力的相互作用;破碎带与断层诱导裂隙带之间存在易滑段与不易滑段,揭示了剪切作用下破碎带空间变形非均匀特征;破碎带中岩体颗粒物质的重新排列,引起易滑段与不易滑段的动态演化。(2)破碎带中较大粒径角砾岩颗粒承载了断层上下盘之间的主要挤压及摩擦力,起到了骨架支撑的作用;随着剪力的增长,强力链方向发生偏转,向竖直方向靠拢。(3)处于高应力状态的断层远离破碎带边缘位置岩体颗粒更容易发生破坏、碎裂、重新排列,从而引起强力链空间方位的变化;随着竖向荷载的增大,强力链空间方位由明显各向非均匀性向各向均匀性转变。(4)竖向荷载变化对断层破碎带中力链比例和颗粒接触力分布频率影响较小,对力链空间分布及强度影响较大。
The formation mechanism and evolution of force chain in the granular media system of fault fracture zone are important foundations for studying the occurrence of geological disasters such as creep,stick-slip and earthquake.By photo-elastic test device of particles under biaxial loading and bilateral flowing conditions,the macro-mechanical characteristics,the network structure and evolution,the spatial distribution and strength of force chain in the fracture zone are studied under shear.The results show that in fault fracture zone,the interaction between particles of rock mass is transmitted through the force chain.There are easy sliding section and non-easy sliding section between the fracture zone and the fault-induced fracture zone,which reveals the non-uniform characteristics of spatial deformation of the fracture zone under shear.The rearrangement of rock particles in the fracture zone results in the dynamic evolution of easy sliding sections and non-easy sliding sections.The larger-sized breccia particles in the fracture zone carry the main compression and friction between the upper and lower plates of the fault,which plays the role of"skeleton support".With the increase of shear force,the direction of the strong force chain is deflected in the vertical direction.Rock particles near the middle of the fracture zone are more likely to be destroyed,fractured and rearranged when the fault is in a high stress state,which results in the change of spatial orientation of strong force chain.With the increase of vertical load,the spatial orientation of strong force chain changes from obvious anisotropy to uniform isotropy.The change of vertical load has little effect on the force chain ratio and the distribution of particle contact force frequency in fault fracture zone,but has great influence on the spatial distribution and strength of the force chain.
作者
展亚太
王金安
李飞
杨柳
ZHAN Ya-tai;WANG Jin-an;LI Fei;YANG Liu(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines,University of Science and Technology Beijing,Beijing 100083,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第8期2627-2635,共9页
Rock and Soil Mechanics
基金
国家重点基础研究发展计划(十三五)项目(No.2017YFC1503104)。
关键词
断层破碎带
剪切滑动
光弹试验
力链演化
fault fracture zone
shear slip
photo-elastic experiment
force chain evolution
