深部硬岩矩形隧洞围岩板裂破坏的试验模拟研究
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摘要
为了深入认识深部硬岩矩形隧洞围岩板裂破坏的发生机制,利用花岗岩材料加工含预制矩形孔洞(40 mm×40 mm)的立方体试样(100 mm×100 mm×100 mm),并采用TRW-3000岩石真三轴电液伺服诱变试验机进行了模拟试验研究。模拟试验中首先以深部1 000 m的地应力条件作为初始加载应力状态,保持孔洞径向和轴向的水平向应力不变,然后在竖直向加载直至孔洞两侧洞壁围岩发生破坏,并保证试样整体始终处于稳定状态。加载过程中利用岩样内部结构破坏实时视频监控系统,进行全程的实时记录和监测。试验结果表明,在竖直向为最大主应力和水平轴向为中间主应力的情况下,矩形孔洞两侧洞壁围岩整体发生明显的板裂破坏,破坏区域呈对称状,而顶板和底板始终保持稳定状态。侧壁围岩的破坏方向平行于竖直向,呈现典型的张拉板裂状破坏特征。整个破坏过程划分为平静期阶段、洞壁两侧上下肩角处颗粒弹射阶段、侧壁围岩裂纹扩展阶段和裂纹贯通板裂破坏阶段。当进入到裂纹贯通板裂破坏阶段时,无论是加载还是保载过程,板裂破坏都可能持续发展。试验过程中,试样洞壁两侧围岩的板裂破坏整体上呈现静态破坏模式,而且破坏区域沿水平方向逐渐向洞壁深部发展,最终形成沿轴向的贯穿型对称弧形槽。
This study is aimed to investigate the spalling failure mechanism of surrounding rock in the rectangular tunnel of deep hard rock. A cubic granite specimen(100 mm×100 mm×100 mm) was prepared with a precast rectangular hole(40 mm×40 mm), and then the simulation test was carried out by using the TRW-3000 true triaxial electro-hydraulic servo mutagenesis testing machine. In the simulation test, the in-situ stress of the depth of 1 000 m was selected as the initial loading stress state, and the horizontal stresses of the rectangular hole were kept constant in the radial and axial directions. After that, the vertical loading was applied until the surrounding rock on both sidewalls of the hole was destroyed, and the whole specimen remained in a stable state. During the loading process, a real-time video surveillance system was employed to monitor the failure process of the internal structure of the rock specimen. The results showed that when the maximum principal stress was at the vertical direction and the intermediate principal stress was at the horizontal axis, the obvious spalling failure appeared on the surrounding rock of both sidewalls of the rectangular hole. Moreover, it was found that the failure zone of the surrounding rock was symmetrical, whereas the roof and the floor remained stable. Meanwhile, the failure of surrounding rock was parallel to the vertical direction, showing typical tensile cracking and spalling characteristics. The entire failure process was divided into the calm stage, the particle ejection stage on the shoulder angles of the hole,the sidewall crack propagation stage and the crack penetration spalling stage at both sidewalls. When entering the crack penetration spalling stage, the spalling failure may continue to develop regardless of the loading or load-holding process. During the test, the spalling failure of the surrounding rock on the both sidewalls of the specimen presented a static failure mode. Besides, the failure zone gradually developed towards the deep part of the wall along the horizontal direction, and finally formed a penetrating symmetric arc notch along the axial direction.
This study is aimed to investigate the spalling failure mechanism of surrounding rock in the rectangular tunnel of deep hard rock. A cubic granite specimen(100 mm×100 mm×100 mm) was prepared with a precast rectangular hole(40 mm×40 mm), and then the simulation test was carried out by using the TRW-3000 true triaxial electro-hydraulic servo mutagenesis testing machine. In the simulation test, the in-situ stress of the depth of 1 000 m was selected as the initial loading stress state, and the horizontal stresses of the rectangular hole were kept constant in the radial and axial directions. After that, the vertical loading was applied until the surrounding rock on both sidewalls of the hole was destroyed, and the whole specimen remained in a stable state. During the loading process, a real-time video surveillance system was employed to monitor the failure process of the internal structure of the rock specimen. The results showed that when the maximum principal stress was at the vertical direction and the intermediate principal stress was at the horizontal axis, the obvious spalling failure appeared on the surrounding rock of both sidewalls of the rectangular hole. Moreover, it was found that the failure zone of the surrounding rock was symmetrical, whereas the roof and the floor remained stable. Meanwhile, the failure of surrounding rock was parallel to the vertical direction, showing typical tensile cracking and spalling characteristics. The entire failure process was divided into the calm stage, the particle ejection stage on the shoulder angles of the hole,the sidewall crack propagation stage and the crack penetration spalling stage at both sidewalls. When entering the crack penetration spalling stage, the spalling failure may continue to develop regardless of the loading or load-holding process. During the test, the spalling failure of the surrounding rock on the both sidewalls of the specimen presented a static failure mode. Besides, the failure zone gradually developed towards the deep part of the wall along the horizontal direction, and finally formed a penetrating symmetric arc notch along the axial direction.
引文
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[10]王学滨,伍小林,潘一山.圆形巷道围岩层裂或板裂化的等效连续介质模型及侧压系数的影响[J].岩土力学,2012,33(8):2395-2402.WANG Xue-bin,WU Xiao-lin,PAN Yi-shan.An equivalent continuum model for exfoliation or slabbing phenomenon of surrounding rock of circular tunnel and effects of lateral pressure coefficients[J].Rock and Soil Mechanics,2012,33(8):2395-2402.
[11]侯哲生,龚秋明,矫伟刚,等.深埋圆形隧洞板裂化弧形岩板凹曲变形的论证[J].岩土工程学报,2013,35(3):551-558.HOU Zhe-sheng,GONG Qiu-ming,JIAO Wei-gang,et al.Demonstration of concave deformation of arc-shaped rock slabs in deep circular tunnels[J].Chinese Journal of Geotechnical Engineering,2013,35(3):551-558.
[12]周辉,徐荣超,卢景景,等.板裂化模型试样失稳破坏及其裂隙扩展特征的试验研究[J].岩土力学,2015,36(增刊2):1-11.ZHOU Hui,XU Rong-chao,LU Jing-jing,et al.Experimental study of instability destruction and crack propagation characteristics of slab failure model specimen[J].Rock and Soil Mechanics,2015,36(Suppl.2):1-11.
[13]周辉,徐荣超,卢景景,等.深埋隧洞板裂屈曲岩爆机制及物理模拟试验研究[J].岩石力学与工程学报,2015,34(增刊2):3658-3666.ZHOU Hui,XU Rong-chao,LU Jing-jing,et al.Study on mechanisms and physical simulation experiment of slab buckling rockburst in deep tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.2):3658-3666.
[14]周辉,卢景景,胡善超,等.开挖断面曲率半径对高应力下硬脆性围岩板裂化的影响[J].岩土力学,2016,37(1):140-146.ZHOU Hui,LU Jing-jing,HU Shan-chao,et al.Influence of curvature radius of tunnels excavation section on slabbing of hard brittle rockmass under high stress[J].Rock and Soil Mechanics,2016,37(1):140-146.
[15]宫凤强,罗勇,司雪峰,等.深部圆形隧洞板裂屈曲岩爆的模拟试验研究[J].岩石力学与工程学报,2017,36(7):1634-1648.GONG Feng-qiang,LUO Yong,SI Xue-feng,et al.Experimental modelling on rockburst in deep hard rock circular tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(7):1634-1648.
[16]司雪峰,宫凤强,罗勇,等.深部三维圆形洞室岩爆过程的模拟试验[J].岩土力学,2018,39(2):621-634.SI Xue-feng,GONG Feng-qiang,LUO Yong,et al.SExperimental simulation on rockburst process of deep three-dimensional circular cavern[J].Rock and Soil Mechanics,2018,39(2):621-634.
[17]施高萍,祝江鸿,李保海,等.矩形巷道孔边应力的弹性分析[J].岩土力学,2014,35(9):2587-2593.SHI Gao-ping,ZHU Jiang-hong,LI Bao-hai,et al.Elastic analysis of hole-edge stress of rectangular roadway[J].Rock and Soil Mechanics,2014,35(9):2587-2593.
[18]王爱辉.矩形巷道围岩受力与变形破坏特性试验研究[D].西安:西安科技大学,2014.WANG Ai-hui.Experimental study on the force and deformation damage characteristics of the surrounding rock in rectangular roadway[D].Xi'an:Xi'an University of Science and Technology,2014.
[19]李小军,袁瑞甫,赵兴东.矩形巷道围岩破坏规律数值模拟[J].矿业工程,2008,6(2):18-20.LI Xiao-jun,YUAN Rui-fu,ZHAO Xing-dong.Numerical simulation of failure law of rectangular road[J].Mining Engineering,2008,6(2):18-20.
[20]侯化强,王连国,陆银龙,等.矩形巷道围岩应力分布及其破坏机理研究[J].地下空间与工程学报,2011,7(增刊2):1625-1629.HOU Hua-qiang,WANG Lian-guo,LU Yin-long,et al.Study on stress distribution and failure mechanism of surrounding rock in rectangular roadway[J].Chinese Journal of Underground Space and Engineering,2011,7(Suppl.2):1625-1629.
[21]STEPHANSSON O,SARKKA P,MYRVANG A A.State of stress in Fennoscandia[C]//Proceedings of Rock Stress and Rock Stress Measurements.Stockholm:[s.n.],1986:21-32.
[22]张传庆,冯夏庭,周辉,等.深部试验隧洞围岩脆性破坏及数值模拟[J].岩石力学与工程学报,2010,29(10):2063-2068.ZHANG Chuan-qing,FENG Xia-ting,ZHOU Hui,et al.Brittle failure of surrounding rock mass in deep test tunnels and its numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):2063-2068.
[23]HOEK E,KAISER P K,BAWDEN W F.Support of underground excavations in hard rock[M].Rotterdam:A.A.Balkema,1995.
[24]CAI M,KAISER P K.Rockburst support reference book-Volume I:rockburst phenomenon and support characteristics[M].Sudbury,Ontario:Mining Innovation,Laurentian University,2018.
[2]GONG F Q,SI X F,LI X B,et al.Experimental investigation of strain rockburst in circular caverns under deep three-dimensional high-stress conditions[J].Rock Mechanics and Rock Engineering,2019,52(5):1459-1474.
[3]LI X B,GONG F Q,TAO M,et al.Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining:a review[J].Journal of Rock Mechanics and Geotechnical Engineering,2017,9(4):767-782.
[4]GONG Feng-qiang,LUO Yong,LI Xi-bing,et al.Experimental simulation investigation on rockburst induced by spalling failure in deep circular tunnels[J].Tunnelling and Underground Space Technology,2018,81:413-427.
[5]GONG Q M,YIN L J,WU S Y,et al.Rock burst and slabbing failure and its influence on TBM excavation at headrace tunnels in Jinping II hydropower station[J].Engineering Geology,2012,124:98-108.
[6]CAI M,KAISER PK.In-situ rock spalling strength near excavation boundaries[J].Rock Mechanics and Rock Engineering,2014,47(2):659-675.
[7]周辉,卢景景,徐荣超,等.深埋硬岩隧洞围岩板裂化破坏研究的关键问题及研究进展[J].岩土力学,2015,36(10):2737-2749.ZHOU Hui,LU Jing-jing,XU Rong-chao,et al.Critical problems of study of slabbing failure of surrounding rock in deep hard rock tunnel and research progress[J].Rock and Soil Mechanics,2015,36(10):2737-2749.
[8]LIU Guo-feng,FENG Xia-ting,JIANG Quan.In situ observation of spalling process of intact rock mass at large cavern excavation[J].Engineering Geology,2017,226:52-69.
[9]孙卓恒,侯哲生,张爱萍.锦屏二级水电站大理岩拉张型板裂化破坏研究[J].水利与建筑工程学报,2012,10(2):24-27.SUN Zhuo-heng,HOU Zhe-sheng,ZHANG Ai-ping.Research on tensile slabbing failure of marble at JinpingⅡHydropower Station[J].Journal of Water Resources and Architectural Engineering,2012,10(2):24-27.
[10]王学滨,伍小林,潘一山.圆形巷道围岩层裂或板裂化的等效连续介质模型及侧压系数的影响[J].岩土力学,2012,33(8):2395-2402.WANG Xue-bin,WU Xiao-lin,PAN Yi-shan.An equivalent continuum model for exfoliation or slabbing phenomenon of surrounding rock of circular tunnel and effects of lateral pressure coefficients[J].Rock and Soil Mechanics,2012,33(8):2395-2402.
[11]侯哲生,龚秋明,矫伟刚,等.深埋圆形隧洞板裂化弧形岩板凹曲变形的论证[J].岩土工程学报,2013,35(3):551-558.HOU Zhe-sheng,GONG Qiu-ming,JIAO Wei-gang,et al.Demonstration of concave deformation of arc-shaped rock slabs in deep circular tunnels[J].Chinese Journal of Geotechnical Engineering,2013,35(3):551-558.
[12]周辉,徐荣超,卢景景,等.板裂化模型试样失稳破坏及其裂隙扩展特征的试验研究[J].岩土力学,2015,36(增刊2):1-11.ZHOU Hui,XU Rong-chao,LU Jing-jing,et al.Experimental study of instability destruction and crack propagation characteristics of slab failure model specimen[J].Rock and Soil Mechanics,2015,36(Suppl.2):1-11.
[13]周辉,徐荣超,卢景景,等.深埋隧洞板裂屈曲岩爆机制及物理模拟试验研究[J].岩石力学与工程学报,2015,34(增刊2):3658-3666.ZHOU Hui,XU Rong-chao,LU Jing-jing,et al.Study on mechanisms and physical simulation experiment of slab buckling rockburst in deep tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(Suppl.2):3658-3666.
[14]周辉,卢景景,胡善超,等.开挖断面曲率半径对高应力下硬脆性围岩板裂化的影响[J].岩土力学,2016,37(1):140-146.ZHOU Hui,LU Jing-jing,HU Shan-chao,et al.Influence of curvature radius of tunnels excavation section on slabbing of hard brittle rockmass under high stress[J].Rock and Soil Mechanics,2016,37(1):140-146.
[15]宫凤强,罗勇,司雪峰,等.深部圆形隧洞板裂屈曲岩爆的模拟试验研究[J].岩石力学与工程学报,2017,36(7):1634-1648.GONG Feng-qiang,LUO Yong,SI Xue-feng,et al.Experimental modelling on rockburst in deep hard rock circular tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(7):1634-1648.
[16]司雪峰,宫凤强,罗勇,等.深部三维圆形洞室岩爆过程的模拟试验[J].岩土力学,2018,39(2):621-634.SI Xue-feng,GONG Feng-qiang,LUO Yong,et al.SExperimental simulation on rockburst process of deep three-dimensional circular cavern[J].Rock and Soil Mechanics,2018,39(2):621-634.
[17]施高萍,祝江鸿,李保海,等.矩形巷道孔边应力的弹性分析[J].岩土力学,2014,35(9):2587-2593.SHI Gao-ping,ZHU Jiang-hong,LI Bao-hai,et al.Elastic analysis of hole-edge stress of rectangular roadway[J].Rock and Soil Mechanics,2014,35(9):2587-2593.
[18]王爱辉.矩形巷道围岩受力与变形破坏特性试验研究[D].西安:西安科技大学,2014.WANG Ai-hui.Experimental study on the force and deformation damage characteristics of the surrounding rock in rectangular roadway[D].Xi'an:Xi'an University of Science and Technology,2014.
[19]李小军,袁瑞甫,赵兴东.矩形巷道围岩破坏规律数值模拟[J].矿业工程,2008,6(2):18-20.LI Xiao-jun,YUAN Rui-fu,ZHAO Xing-dong.Numerical simulation of failure law of rectangular road[J].Mining Engineering,2008,6(2):18-20.
[20]侯化强,王连国,陆银龙,等.矩形巷道围岩应力分布及其破坏机理研究[J].地下空间与工程学报,2011,7(增刊2):1625-1629.HOU Hua-qiang,WANG Lian-guo,LU Yin-long,et al.Study on stress distribution and failure mechanism of surrounding rock in rectangular roadway[J].Chinese Journal of Underground Space and Engineering,2011,7(Suppl.2):1625-1629.
[21]STEPHANSSON O,SARKKA P,MYRVANG A A.State of stress in Fennoscandia[C]//Proceedings of Rock Stress and Rock Stress Measurements.Stockholm:[s.n.],1986:21-32.
[22]张传庆,冯夏庭,周辉,等.深部试验隧洞围岩脆性破坏及数值模拟[J].岩石力学与工程学报,2010,29(10):2063-2068.ZHANG Chuan-qing,FENG Xia-ting,ZHOU Hui,et al.Brittle failure of surrounding rock mass in deep test tunnels and its numerical simulation[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):2063-2068.
[23]HOEK E,KAISER P K,BAWDEN W F.Support of underground excavations in hard rock[M].Rotterdam:A.A.Balkema,1995.
[24]CAI M,KAISER P K.Rockburst support reference book-Volume I:rockburst phenomenon and support characteristics[M].Sudbury,Ontario:Mining Innovation,Laurentian University,2018.