含直墙拱形洞室坚硬流纹岩双轴压缩试验研究
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摘要
为揭示含直墙拱形洞室岩石的变形及破裂规律,本文利用现场采集的流纹岩,制取圆柱形试样和内含直墙拱形洞室的方形试样,对圆柱形试样进行单轴压缩试验检测其力学特性,对含直墙拱形洞室的方形试样进行双轴压缩试验,检测其围岩变形和破裂特征。研究结果表明:单轴压缩试验中,流纹岩表现出明显的脆性特征,产生竖向劈裂破坏;含拱形洞室岩样破坏时首先在起拱线和拱脚处出现裂纹,随着荷载增大,裂隙不断向加载端面扩展并相互连接,拱形洞室底部和直墙出现片帮现象,拱脚压剪破碎,拱顶张性裂隙贯通形成稳定楔体;随着竖向外荷载的增大,拱形洞室围岩竖向和水平应力变化规律与洞室边界形状及与洞室距离有关;起拱线和拱脚处应力集中明显,拱脚处应力集中程度较大、主应力方向变化不稳定是造成局部破碎的主要原因。试验成果可以为裂隙发育岩体中隧道围岩稳定性研究提供参考。
In order to reveal the failure and deformation characteristics of arched opening in natural cracked rock,the rhyolite that was collected on site was used to make the cylindrical specimens and the rectangular prism specimen with straight wall and arched opening.Uniaxial tests were performed on the cylindrical specimens to obtain the mechanical characteristics,while biaxial tests were performed on the rectangular prism specimen to measure the deformation and failure characteristics.The results of the study indicated that:(1)under uniaxial compression tests,the rhyolite exhibited brittleness and vertical splitting failure.(2)For the rectangular prism specimen,the cracks first initiated around the springing line and skewback,and then they propagated to the loading end and were connected each other with the increasing of vertical pressure.Spalling was observed at the bottom and straight wall of the opening,with compression and shear fracture occuring at the skewback,and tensional cracks being propagated to form the stable wedges.(3)With the increasing of vertical loading,the variation rules of horizontal and vertical stress of the rock around the opening were related to the shape of the opening and the distance to the opening.(4)The stress concentration at both the springing line and skewback was significant.The main cause of local fragmentation was the stress concentration at the skewback and the instability of the direction of the principal stress.The results can provide references to the further study on the stability of the surrounding rock of tunnels in factured rock mass.
In order to reveal the failure and deformation characteristics of arched opening in natural cracked rock,the rhyolite that was collected on site was used to make the cylindrical specimens and the rectangular prism specimen with straight wall and arched opening.Uniaxial tests were performed on the cylindrical specimens to obtain the mechanical characteristics,while biaxial tests were performed on the rectangular prism specimen to measure the deformation and failure characteristics.The results of the study indicated that:(1)under uniaxial compression tests,the rhyolite exhibited brittleness and vertical splitting failure.(2)For the rectangular prism specimen,the cracks first initiated around the springing line and skewback,and then they propagated to the loading end and were connected each other with the increasing of vertical pressure.Spalling was observed at the bottom and straight wall of the opening,with compression and shear fracture occuring at the skewback,and tensional cracks being propagated to form the stable wedges.(3)With the increasing of vertical loading,the variation rules of horizontal and vertical stress of the rock around the opening were related to the shape of the opening and the distance to the opening.(4)The stress concentration at both the springing line and skewback was significant.The main cause of local fragmentation was the stress concentration at the skewback and the instability of the direction of the principal stress.The results can provide references to the further study on the stability of the surrounding rock of tunnels in factured rock mass.
引文
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[3]李培楠,刘俊,苏锋,等.任意形状隧道围岩应力与位移的解析延拓求解[J].同济大学学报:自然科学版,2013,41(10):1 483-1 489.LI Peinan,LIU Jun,SU Feng,et al.Analytical Continuation Method for Solving Stress and Displacement of Surrounding Rock Buried Tunnel Excavation with Arbitrary Shape Section[J].Journal of Tongji University:Natural Science,2013,41(10):1 483-1 489.
[4]KARGAR A R,RAHMANNEJAD R,HAJABASI M A.A Semi-analytical Elastic Solution for Stress Field of Lined Non-circular Tunnels at Great Depth Using Complex Variable Method[J].International Journal of Solids and Structures,2014,51(6):1 475-1 482.
[5]EXADAKTYLOS G E,STAVROPOULOU M C.A Closedform Elastic Solution for Stresses and Displacements Around Tunnels[J].International Journal of Rock Mechanics and Mining Sciences,2002,39(7):905-916.
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[9]FAKHIMI A,CARVALHO F,ISHIDA T,et al.Simulation of Failure Around a Circular Opening in Rock[J].International Journal of Rock Mechanics and Mining Sciences,2002,39(4):507-515.
[10]SAGONG M,PARK D,YOO J,et al.Experimental and Numerical Analyses of an Opening in a Jointed Rock Mass under Biaxial Compression[J].International Journal of Rock Mechanics and Mining Sciences,2011,48(7):1 055-1 067.
[11]陈陆望,白世伟.坚硬脆性岩体中圆形洞室岩爆破坏的平面应变模型试验研究[J].岩石力学与工程学报,2007,26(12):2 504-2 509.CHEN Luwang,BAI Shiwei.Research on Plane Strain Model Test of Rockburst of Circular Cavern in Hard Brittle Rockmass[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(12):2 504-2 509.
[12]陈陆望,白世伟,殷晓曦,等.坚硬岩体中马蹄形洞室岩爆破坏平面应变模型试验[J].岩土工程学报,2008,30(10):1 520-1 526.CHEN Luwang,BAI Shiwei,YIN Xiaoxi,et al.Planestrain Model Tests on Rock-burst of Horseshoe Section Caverns in Hard and Brittle Rockmass[J].Chinese Journal of Geotechnical Engineering,2008,30(10):1 520-1 526.
[13]宋义敏,潘一山,章梦涛,等.洞室围岩三种破坏形式的试验研究[J].岩石力学与工程学报,2010,29(S1):2 741-2 745.SONG Yimin,PAN Yishan,ZHANG Mengtao,et al.Exprimental Investigation on Fracture of Three Types of Underground Caverns[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(S1):2 741-2 745.
[14]DENG R G,ZHONG Z B,FU X M,et al.Experimental Study on Deformation and Strength Properties of Microfissured Rock[M].Florida:CRC Press,2013:231-234.
[15]钟志彬,邓荣贵,李佳,等.天然裂隙性流纹岩三轴力学特性试验研究[J].岩石力学与工程学报,2014,33(6):1 233-1 240.ZHONG Zhibin,DENG Ronggui,LI Jia,et al.Experimental Study of Triaxial Mechanical Properties of Naturally Fissured Rhyolite[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(6):1 233-1 240.
[16]ZHAO X D,ZHANG H X,ZHU W C.Fracture Evolution Around Pre-existing Cylindrical Cavities in Brittle Rocks under Uniaxial Compression[J].Transactions of Nonferrous Metals Society of China,2014,24(3):806-815.
[17]LAJTAI E Z,CARTER B G,DUNCAN E J S.En Echelon Crack-arrays in Potash Salt Rock[J].Rock Mechanics&Rock Engineering,1994;27(2):89-111.
[18]EWY R T,COOK N G W.Deformation and Fracture Around Cylindrical Openings in Rock—Ⅱ.Initiation,Growth and Interaction of Fractures[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1990,27(5):409-427.
[19]MARTINI C D,READ R S,MARTINO J B.Observations of Brittle Failure Around a Circular Test Tunnel[J].International Journal of Rock Mechanics and Mining Sciences,1997,34(7):1 065-1 073.
[20]房倩,张顶立,王毅远,等.圆形洞室围岩破坏模式模型试验研究[J].岩石力学与工程学报,2011,30(3):564-571.FANG Qian,ZHANG Dingli,WONG Louis Ngai Yuen,et al.Model Test Study of Failure Modes of Surrounding Rock for Circular Caverns[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(3):564-571.
[21]EBERHARDT E.Numerical Modelling of Three-dimension Stress Rotation ahead of an Advancing Tunnel Face[J].International Journal of Rock Mechanics and Mining Sciences,2001,38(4):499-518.
[22]MARTIN C D.Seventeenth Canadian Geotechnical Colloquium:The Effect of Cohesion Loss and Stress Path on Brittle Rock Strength[J].Canadian Geotednical Journal,1997,34(5):698-725.
[23]CARTER B J.Size and Stress Gradient Effects on Fracture Around Cavities[J].Rock Mechanics&Rock Engineering,1992,25(3):167-186.
[24]GERMANOVICH L N,DYSKIN A V.Fracture Mechanisms and Instability of Openings in Compression[J].Internation Journal of Rock Mechanics and Mining Sciences,2000,37(1-2):263-284.
[2]朱大勇,钱七虎,周早生,等.复杂形状洞室围岩应力弹性解析分析[J].岩石力学与工程学报,1999,18(4):34-36.ZHU Dayong,QIAN Qihu,ZHOU Zaosheng,et al.Elastic Solution to Stresses of Rock Masses Around Round Openings with Complex Shape[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(4):34-36.
[3]李培楠,刘俊,苏锋,等.任意形状隧道围岩应力与位移的解析延拓求解[J].同济大学学报:自然科学版,2013,41(10):1 483-1 489.LI Peinan,LIU Jun,SU Feng,et al.Analytical Continuation Method for Solving Stress and Displacement of Surrounding Rock Buried Tunnel Excavation with Arbitrary Shape Section[J].Journal of Tongji University:Natural Science,2013,41(10):1 483-1 489.
[4]KARGAR A R,RAHMANNEJAD R,HAJABASI M A.A Semi-analytical Elastic Solution for Stress Field of Lined Non-circular Tunnels at Great Depth Using Complex Variable Method[J].International Journal of Solids and Structures,2014,51(6):1 475-1 482.
[5]EXADAKTYLOS G E,STAVROPOULOU M C.A Closedform Elastic Solution for Stresses and Displacements Around Tunnels[J].International Journal of Rock Mechanics and Mining Sciences,2002,39(7):905-916.
[6]EXADAKTYLOS G E,LIOLIOS PA,STAVROPOULOU M C.A Semi-analytical Elastic Stress-displacement Solution for Notched Circular Openings in Rocks[J].International Journal of Solids and Structures,2003,40(5):1 165-1 187.
[7]ZHU W C,LIU J,TANG C A,et al.Simulation of Progressive Fracturing Processes Around Underground Excavations under Biaxial Compression[J].Tunnelling and Underground Space Technology,2005,20(3):231-247.
[8]WANG S Y,SLOAN S W,SHENG D C,et al.Numerical Analysis of the Failure Process Around a Circular Opening in Rock[J].Computers and Geotechnics,2012,39:8-16.
[9]FAKHIMI A,CARVALHO F,ISHIDA T,et al.Simulation of Failure Around a Circular Opening in Rock[J].International Journal of Rock Mechanics and Mining Sciences,2002,39(4):507-515.
[10]SAGONG M,PARK D,YOO J,et al.Experimental and Numerical Analyses of an Opening in a Jointed Rock Mass under Biaxial Compression[J].International Journal of Rock Mechanics and Mining Sciences,2011,48(7):1 055-1 067.
[11]陈陆望,白世伟.坚硬脆性岩体中圆形洞室岩爆破坏的平面应变模型试验研究[J].岩石力学与工程学报,2007,26(12):2 504-2 509.CHEN Luwang,BAI Shiwei.Research on Plane Strain Model Test of Rockburst of Circular Cavern in Hard Brittle Rockmass[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(12):2 504-2 509.
[12]陈陆望,白世伟,殷晓曦,等.坚硬岩体中马蹄形洞室岩爆破坏平面应变模型试验[J].岩土工程学报,2008,30(10):1 520-1 526.CHEN Luwang,BAI Shiwei,YIN Xiaoxi,et al.Planestrain Model Tests on Rock-burst of Horseshoe Section Caverns in Hard and Brittle Rockmass[J].Chinese Journal of Geotechnical Engineering,2008,30(10):1 520-1 526.
[13]宋义敏,潘一山,章梦涛,等.洞室围岩三种破坏形式的试验研究[J].岩石力学与工程学报,2010,29(S1):2 741-2 745.SONG Yimin,PAN Yishan,ZHANG Mengtao,et al.Exprimental Investigation on Fracture of Three Types of Underground Caverns[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(S1):2 741-2 745.
[14]DENG R G,ZHONG Z B,FU X M,et al.Experimental Study on Deformation and Strength Properties of Microfissured Rock[M].Florida:CRC Press,2013:231-234.
[15]钟志彬,邓荣贵,李佳,等.天然裂隙性流纹岩三轴力学特性试验研究[J].岩石力学与工程学报,2014,33(6):1 233-1 240.ZHONG Zhibin,DENG Ronggui,LI Jia,et al.Experimental Study of Triaxial Mechanical Properties of Naturally Fissured Rhyolite[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(6):1 233-1 240.
[16]ZHAO X D,ZHANG H X,ZHU W C.Fracture Evolution Around Pre-existing Cylindrical Cavities in Brittle Rocks under Uniaxial Compression[J].Transactions of Nonferrous Metals Society of China,2014,24(3):806-815.
[17]LAJTAI E Z,CARTER B G,DUNCAN E J S.En Echelon Crack-arrays in Potash Salt Rock[J].Rock Mechanics&Rock Engineering,1994;27(2):89-111.
[18]EWY R T,COOK N G W.Deformation and Fracture Around Cylindrical Openings in Rock—Ⅱ.Initiation,Growth and Interaction of Fractures[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1990,27(5):409-427.
[19]MARTINI C D,READ R S,MARTINO J B.Observations of Brittle Failure Around a Circular Test Tunnel[J].International Journal of Rock Mechanics and Mining Sciences,1997,34(7):1 065-1 073.
[20]房倩,张顶立,王毅远,等.圆形洞室围岩破坏模式模型试验研究[J].岩石力学与工程学报,2011,30(3):564-571.FANG Qian,ZHANG Dingli,WONG Louis Ngai Yuen,et al.Model Test Study of Failure Modes of Surrounding Rock for Circular Caverns[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(3):564-571.
[21]EBERHARDT E.Numerical Modelling of Three-dimension Stress Rotation ahead of an Advancing Tunnel Face[J].International Journal of Rock Mechanics and Mining Sciences,2001,38(4):499-518.
[22]MARTIN C D.Seventeenth Canadian Geotechnical Colloquium:The Effect of Cohesion Loss and Stress Path on Brittle Rock Strength[J].Canadian Geotednical Journal,1997,34(5):698-725.
[23]CARTER B J.Size and Stress Gradient Effects on Fracture Around Cavities[J].Rock Mechanics&Rock Engineering,1992,25(3):167-186.
[24]GERMANOVICH L N,DYSKIN A V.Fracture Mechanisms and Instability of Openings in Compression[J].Internation Journal of Rock Mechanics and Mining Sciences,2000,37(1-2):263-284.