深部岩体岩芯饼化特征分析与形成机制研究
|
摘要
以锦屏II级水电站深埋试验洞内长度大于1 500 m的钻孔岩芯为研究对象,统计饼化岩芯断口的宏观破坏特征、饼化数量和厚度,结合声波和数字钻孔摄像测试结果,分析岩体埋深、岩体结构、洞径尺寸、钻孔直径和钻孔方位对岩芯饼化的影响,得到岩芯饼化的空间分布规律;并通过断口电镜扫描试验,得到岩芯饼化的微观断裂机制。分析结果表明:(1)饼化数量与厚度分布符合乘幂函数形式,饼化程度随埋深和洞径尺寸的增大而增大,3倍洞径内岩芯饼化数量最多;(2)饼化岩芯凹凸面的形成与应力分布、内部损伤和矿物结构类型有关;(3)岩芯饼化是地质作用和外界扰动共同作用下发生的,原生微缺陷、结构面和开挖损伤是岩芯饼化起裂的基础,开挖后地应力调整和取芯局部应力解除是岩芯断裂的动力,而持续钻进是促使岩芯周期性断裂成饼的根本原因;钻孔径向压剪、岩芯侧向膨胀和轴向拉伸是岩芯饼化断裂的力学响应;(4)岩芯饼化分区性特征是围岩损伤弱化分区、岩体结构和应力场分布叠加的综合反映。
According to borehole cores with the length more than 1 500 m in deep tunnels at Jinping II hydropower station,the information of the macro-damaged characteristics,quantity and thickness distribution of discing core were collected and the spatial distribution of core discing was analyzed.Then,the influences of different buried depths,geologic structure,tunnel geometric size,drilling diameter and directions on core discing were studied in combination with the results of elastic wave test and digital borehole images.Simultaneously,by applying scanning electron microscope technique for discs? surface,the micro-damage mechanism was discussed.The results indicated that:(1) The relationship between the quantity and thickness distribution was similar to a power function form.The quantity of core discing increased with depth and tunnel dimension.Within the zone of 3 times of tunnel diameter,core discing occurred more frequently.(2) The convex-concave formation was related to stress distribution,internal damage and mineral structure types.(3) Core discing often occurred under the joint action of geological and external effects.The native micro defects,structural plane and external disturbance were the discing foundation;the local stress concentration and stress release were the power of discing;the continuous drilling was the intrinsic cause of core broken into pies;the radial cut-compressive,axial tensile stress and lateral expansion of rock cores were the mechanical response of rock mass fracture.(4) Discing zone characteristics were the comprehensive reflection of rock damage weakening,rock mass structure and local stress concentration.
According to borehole cores with the length more than 1 500 m in deep tunnels at Jinping II hydropower station,the information of the macro-damaged characteristics,quantity and thickness distribution of discing core were collected and the spatial distribution of core discing was analyzed.Then,the influences of different buried depths,geologic structure,tunnel geometric size,drilling diameter and directions on core discing were studied in combination with the results of elastic wave test and digital borehole images.Simultaneously,by applying scanning electron microscope technique for discs? surface,the micro-damage mechanism was discussed.The results indicated that:(1) The relationship between the quantity and thickness distribution was similar to a power function form.The quantity of core discing increased with depth and tunnel dimension.Within the zone of 3 times of tunnel diameter,core discing occurred more frequently.(2) The convex-concave formation was related to stress distribution,internal damage and mineral structure types.(3) Core discing often occurred under the joint action of geological and external effects.The native micro defects,structural plane and external disturbance were the discing foundation;the local stress concentration and stress release were the power of discing;the continuous drilling was the intrinsic cause of core broken into pies;the radial cut-compressive,axial tensile stress and lateral expansion of rock cores were the mechanical response of rock mass fracture.(4) Discing zone characteristics were the comprehensive reflection of rock damage weakening,rock mass structure and local stress concentration.
引文
[1]OBERT L,STEPHENSON D E.Stress conditions under which core discing occurs[J].Society of Mining Engineers,1965,(9):227–235.
[2]KAGA N,MATSUKI K,SAKAGUCHI K.The in-situ stress states associated with core discing estimated by analysis of principal tensile stress[J].International Journal of Rock Mechanics and Mining Sciences,2003,40(5):653–665.
[3]MATSUKI K,KAGA N,YOKOYAMA T,et al.Determination of three dimensional in situ stress from core discing based on analysis of principal tensile stress[J].International Journal of Rock Mechanics and Mining Sciences,2004,41(7):1 167–1 190.
[4]尚岳全,孙琪.天荒坪电站岩芯饼化机制分析[J].地质灾害与环境保护,1991,2(2):49–52.(SHANG Yuequan,SUN Qi.Analysis core mechanism of Tianhuangping powerstation[J].Geological Hazards and Environment Preservation,1991,2(2):49–52.(in Chinese))
[5]李树森,聂德新,任光明.岩芯饼裂机制及其对工程地质特性影响的分析[J].地球科学进展,2004,19(增1):376–379.(LI Shusen,NIE Dexin,REN Guangming.The fracture mechanism of discal drill core and its influence on characteristic of engineering geology[J].Advance in Earth Sciences,2004,19(Supp.1):376–379.(in Chinese))
[6]阮小平,李方全.茅坪800 m钻孔饼状岩芯分析[J].地震学报,1994,16(2):190–194.(YUAN Xiaoping,LI fangquan.Analysis of core discing of Maoping 800 m drilling hole[J].Acta Seismologica Sinica,1994,16(2):190–194.(in Chinese))
[7]刘竹华,姚宝魁,杨家录.钻孔岩芯饼状断裂破坏机制[J].工程地质学报,1997,5(4):330–334.(LIU Zhuhua,YAO Baokui,YANG Jialu.Fracture mechanism of the discal drill core[J].Journal of Engineering Geology,1997,5(4):330–334.(In Chinese))
[8]LIM S S,MARTIN C D.Core discing and its relationship with stress magnitude for Lac du Bonnet granite[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(2):254–264.
[9]姜谙男,曾正文,唐春安.岩芯成饼单元安全度三维数值试验及地应力反馈分析[J].岩石力学与工程学报,2010,29(8):1 610–1 617.(JIANG Annan,ZENG Zhengwen,TANG Chun′an.Three-dimensional numerical test of element safety degree of rock core discing and feed-back analysis of geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(8):1 610–1 617.(in Chinese))
[10]BUNGER A P.Stochastic Analysis of core discing for estimation of in situ stress[J].Rock Mechanics and Rock Engineering,2010,43(3):275–286.
[11]CORTHESY R,LEITE M H.A strain-softening numerical model of core discing and damage[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(3):329–350.
[12]KANG S S,ISHIGURO Y,OBARA Y.Evaluation of core disking rock stress and tensile strength via the compact conical-ended borehole overcoring technique[J].International Journal of Rock Mechanics and Mining Sciences,2006,43(8):1 226–1 240.
[13]吴世勇,王坚,王鸽.锦屏水电站辅助洞工程地下水及治理对策[J].岩石力学与工程学报,2007,26(10):1 959–1 967.(WU Shiyong,WANG Jian,WANG Ge.Underground water and its treatment strategy in auxiliary tunnels of Jinping hydropower project[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):1 959–1 967.(in Chinese))
[14]LI S J,FENG X T,LI Z H,et al.In-situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels[J].Science China Technology Sciences,2011,54(Supp.1):1-8.
[2]KAGA N,MATSUKI K,SAKAGUCHI K.The in-situ stress states associated with core discing estimated by analysis of principal tensile stress[J].International Journal of Rock Mechanics and Mining Sciences,2003,40(5):653–665.
[3]MATSUKI K,KAGA N,YOKOYAMA T,et al.Determination of three dimensional in situ stress from core discing based on analysis of principal tensile stress[J].International Journal of Rock Mechanics and Mining Sciences,2004,41(7):1 167–1 190.
[4]尚岳全,孙琪.天荒坪电站岩芯饼化机制分析[J].地质灾害与环境保护,1991,2(2):49–52.(SHANG Yuequan,SUN Qi.Analysis core mechanism of Tianhuangping powerstation[J].Geological Hazards and Environment Preservation,1991,2(2):49–52.(in Chinese))
[5]李树森,聂德新,任光明.岩芯饼裂机制及其对工程地质特性影响的分析[J].地球科学进展,2004,19(增1):376–379.(LI Shusen,NIE Dexin,REN Guangming.The fracture mechanism of discal drill core and its influence on characteristic of engineering geology[J].Advance in Earth Sciences,2004,19(Supp.1):376–379.(in Chinese))
[6]阮小平,李方全.茅坪800 m钻孔饼状岩芯分析[J].地震学报,1994,16(2):190–194.(YUAN Xiaoping,LI fangquan.Analysis of core discing of Maoping 800 m drilling hole[J].Acta Seismologica Sinica,1994,16(2):190–194.(in Chinese))
[7]刘竹华,姚宝魁,杨家录.钻孔岩芯饼状断裂破坏机制[J].工程地质学报,1997,5(4):330–334.(LIU Zhuhua,YAO Baokui,YANG Jialu.Fracture mechanism of the discal drill core[J].Journal of Engineering Geology,1997,5(4):330–334.(In Chinese))
[8]LIM S S,MARTIN C D.Core discing and its relationship with stress magnitude for Lac du Bonnet granite[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(2):254–264.
[9]姜谙男,曾正文,唐春安.岩芯成饼单元安全度三维数值试验及地应力反馈分析[J].岩石力学与工程学报,2010,29(8):1 610–1 617.(JIANG Annan,ZENG Zhengwen,TANG Chun′an.Three-dimensional numerical test of element safety degree of rock core discing and feed-back analysis of geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(8):1 610–1 617.(in Chinese))
[10]BUNGER A P.Stochastic Analysis of core discing for estimation of in situ stress[J].Rock Mechanics and Rock Engineering,2010,43(3):275–286.
[11]CORTHESY R,LEITE M H.A strain-softening numerical model of core discing and damage[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(3):329–350.
[12]KANG S S,ISHIGURO Y,OBARA Y.Evaluation of core disking rock stress and tensile strength via the compact conical-ended borehole overcoring technique[J].International Journal of Rock Mechanics and Mining Sciences,2006,43(8):1 226–1 240.
[13]吴世勇,王坚,王鸽.锦屏水电站辅助洞工程地下水及治理对策[J].岩石力学与工程学报,2007,26(10):1 959–1 967.(WU Shiyong,WANG Jian,WANG Ge.Underground water and its treatment strategy in auxiliary tunnels of Jinping hydropower project[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):1 959–1 967.(in Chinese))
[14]LI S J,FENG X T,LI Z H,et al.In-situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels[J].Science China Technology Sciences,2011,54(Supp.1):1-8.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心