冻融损伤与围压对层状岩石强度各向异性的影响  

Effects of freeze-thaw damage and confining pressure on anisotropy strength of bedded rock

作　　者：张亮 牛富俊 刘明浩 鞠鑫 ZHANG Liang;NIU Fujun;LIU Minghao;JU Xin(State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《冰川冻土》2022年第2期366-375,共10页Journal of Glaciology and Geocryology

基　　金：第二次青藏高原综合科学考察研究项目(2019QZKK0905);国家重点研发计划项目(2018YFC1505001)资助。

摘　　要：层状岩石具有显著的层理面结构,层理面结构的方向决定了岩石的各向异性,相邻层面的岩石物理力学性质差异和连接强度决定了各向异性的强弱,此外,层状岩石的层理结构使其易受冻融循环(FT)等风化作用的影响。为了研究冻融损伤与围压对层状岩石强度各向异性的影响,分别在0、10、20、30和40次的冻融循环和0、5、15、25和40MPa的围压条件下,使用岩石三轴试验系统(GCTS)对五种不同层理倾角的层状砂岩试件进行试验。试验结果显示,冻融循环会使岩石层理面产生裂隙,更易发生沿层理面的剪切滑移破坏,冻融40次后,β=0°的试件单轴抗压强度降低14.5%,而β=67.5°的试件单轴抗压强度降低57.9%,使层状岩石的固有各向异性增强。围压对岩石的各向异性影响与其固有各向异性有关,表现为随着冻融次数的累积,围压对岩石的应力诱导各向异性由起初的增强逐渐转变为抑制。本研究可为寒区层状岩石工程的设计、施工和安全运行提供理论支持。Bedded rock has a significant bedding plane structure.The direction of bedding plane determines the anisotropy of rock,and the strength of anisotropy is determined by the difference of rock physical properties and the connection strength of adjacent layers,its bedding structure nature of the vulnerability to the impact of weathering effects such as freeze-thaw(FT)cycles.In this research,bedded sandstone specimens with different bedding dip angles were tested by rock triaxial test system(GCTS)after 0,10,20,30 and 40 FT cycles and under confining pressures of 0,5,15,25 and 40 MPa.The test results show that the FT cycles causes cracks in the rock bedding plane,and shear slip failure along the bedding plane is more likely to occur.After 40 times of FT cycles,the uniaxial compressive strength of the specimen withβ=0°decreased by14.5%,while the specimen withβ=67.5°decreased by 57.9%,which enhanced the inherent anisotropy of the bedded rock.The influence of confining pressure on rock anisotropy is related to its inherent anisotropy,which shows that with the accumulation of freeze-thaw cycles,the stress-induced anisotropy of rock under confining pressure changes from initial enhancement to inhibition.This study provides theoretical basis for the design,construction and safe operation of bedded rock engineering in cold regions.

关 键 词：层状岩石 冻融循环 应力诱导 围压 各向异性 

分 类 号：P642.14[天文地球—工程地质学] TU452[天文地球—地质矿产勘探]