摘要
为研究含孔洞加锚岩石的力学特性和裂纹扩展规律,采用相似材料制作包含7种支护情况、0°和90°两种层理的含孔洞加锚试件,在MTS815岩石力学试验系统上进行单轴压缩试验,试验后对破裂试件进行CT扫描,分析试件不同部位裂纹分布规律。结果表明,支护结构显著提高了含孔试件的强度值,但不同支护结构的提升效果不同,以锚杆的作用最为显著,混凝土和钢拱架层效果则不太明显。层理不同,支护结构对试件的强度提升效果也不同,支护结构对90°层理试件的围岩强度提升效果要好于0°层理试件。结合试验结果和理论解析解公式发现,锚杆对岩体的锚固作用主要是通过改变锚固区域围岩应力状态和改善围岩力学参数来实现的,而混凝土和钢拱架则可以为孔洞提供支撑压力,有效防止孔洞的剥落、片帮等破坏,有利于维持孔洞的完整性。另外,对破坏后的试件CT扫描断面进行分析,发现锚杆对岩体的锚固作用使岩体一定范围内形成锚固区,锚固区对试件中的裂纹发展具有弱化、止裂和改变其传播路径等作用。
Uniaxial compression test was performed and CT scan images were obtained for the fractured specimens to study the mechanical property and fracture propagation of anchored rock with a hole under uniaxial compression. The results show that the supporting structure enhances greatly the strength of the specimens. However,different supporting structures have different effects of strength improving and the specimens with different beddings have the different effects of strength improving. Furthermore,it was found that the concrete and steel arch bridge can provide the supporting pressure for holes and prevent the damages such as stripping and spalling of holes effectively,which is necessary for maintaining the integrity of holes. Besides,from the analysis to CT scan images of the fracture surfaces of the destroyed specimens,it was found that the anchor effect of the anchor rod in the rock mass enables the rock mass to form an anchoring zone in a certain area. Thus,the anchoring zone can weaken and prevent the fracture development and change the path of fracture propagation in specimens.
引文
[1]SIREN T,KANTIA P,RINNE M.Considerations and observations of stress-induced and construction-induced excavation damage zone in crystalline rock[J].International Journal of Rock Mechanics and Mining Sciences,2015,73:165–174.
[2]MARTINO J B,CHANDLER N A.Excavation-induced damage studies at the Underground Research Laboratory[J].International Journal of Rock Mechanics and Mining Sciences,2004,41(8):1 413–1 426.
[3]ZHU W C,WEI J,ZHAO J,et al.2D numerical simulation on excavation damaged zone induced by dynamic stress redistribution[J].Tunnelling and Underground Space Technology,2014,43(7):315–326.
[4]CAI M,KAISER P K.Assessment of excavation damaged zone using a micromechanics model[J].Tunnelling and Underground Space Technology,2005,20(4):301–310.
[5]张社荣,孙博,王超,等.含孔洞硬岩破坏过程的离散元分析[J].岩石力学与工程学报2012,31(增2):3 855–3 863.(ZHANG Sherong,SUN Bo,WANG Chao,et al.Discrete element analysis of failure process of hard rock with a pre-existing circular opening[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(Supp.2):3 855–3 863.(in Chinese))
[6]谢林茂,朱万成,王述红,等.含孔洞岩石试样三维破裂过程的并行计算分析[J].岩土工程学报,2011,33(9):1 447–1 455.(XIE Linmao,ZHU Wancheng,WANG Shuhong,et al.Three-dimensional parallel computing on failure process of rock specimen with a pre-existing circular opening[J].Chinese Journal of Geotechnical Engineering,2011,33(9):1 447–1 455.(in Chinese))
[7]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(增1):2 741–2 745.(SONG Yimin,PAN Yishan,ZHANG Mengtao,et al.Experimental investigation on fracture of three types of underground caverns[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(Supp.1):2 741–2 745.(in Chinese))
[8]马少鹏,王来贵,赵永红.岩石圆孔结构破坏过程变形场演化的实验研究[J].岩土力学,2006,27(7):1 082–1 086.(MA Shaopeng,WANG Laigui,ZHAO Yonghong.Experimental study on deformation field evolution during failure procedure of a rock borehole structure[J].Rock and Soil Mechanics,2006,27(7):1 082–1 086.(in Chinese))
[9]刘招伟,李元海.含孔洞岩石单轴压缩下变形破裂规律的实验研究[J].工程力学,2010,27(8):133–139.(LIU Zhaowei,LI Yuanhai.Experimental investigation on the deformation and crack behavior of rock specimen with a hole undergoing uniaxial compression load[J].Engineering Mechanics,2010,27(8):133–139.(in Chinese))
[10]李夕兵,王磊,谢晓锋,等.动静载荷作用下含孔洞硬岩损伤演化的核磁共振特性试验研究[J].岩石力学与工程学报,2015,34(10):1 985–1 993.(LI Xibing,WENG Lei,XIE Xiaofeng,et al.Study on the degradation of hard rock with a pre-existing opening under static-dynamic loadings using nuclear magnetic resonance technique[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(10):1 985–1 993.(in Chinese))
[11]李地元,成腾蛟,周韬,等.冲击载荷作用下含孔洞大理岩动态力学破坏特性试验研究[J].岩石力学与工程学报,2015,34(2):249–260.(LI Diyuan,CHENG Tengjiao,ZHOU Tao,et al.Experimental study of the dynamic strength and fracturing characteristics of marble specimens with a single hole under impact loading[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(2):249–260.(in Chinese))
[12]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.
[13]ZHU W C,BRUHNS O T.Simulating excavation damaged zone around a circular opening under hydromechanical conditions[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(5):815–830.
[14]YANG H Q,ZENG Y Y,LAN Y F,et al.Analysis of the excavation damaged zone around a tunnel accounting for geostress and unloading[J].International Journal of Rock Mechanics and Mining Sciences,2014,69:59–66.
[15]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(1):8–16.
[16]WANG S H,LEE C I,RANJITH P G,et al.Modeling the Effects of Heterogeneity and Anisotropy on the excavation damaged/disturbed zone(EDZ)[J].Rock Mechanics and Rock Engineering,2009,42(2):229–258.
[17]TANG C A,WONG R H C,CHAU K T,et al.Modeling of compression-induced splitting failure in heterogeneous brittle porous solids[J].Engineering Fracture Mechanics,2005,72(4):597–615.
[18]MARTIN C D.Seventeenth Canadian geotechnical colloquium:the effect of cohesion loss and stress path on brittle rock strength[J].Canadian Geotechnical Journal,1997,34(5):698–725.
[19]JIA P,ZHU W C.Mechanism of zonal disintegration around deep underground excavations under triaxial stress-Insight from numerical test[J].Tunnelling and Underground Space Technology,2015,48:1–10.
[20]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.
[21]DZIK E J,LAJTAI E Z.Primary fracture propagation from circular cavities loaded in compression[J].International Journal of Fracture,1996,79(1):49–64.
[22]朱谭谭,靖洪文,苏海健,等.含双圆形孔洞砂岩单轴压缩力学特性试验研究[J].岩土工程学报,2015,37(6):1 047–1 056.(ZHU Tantan,JING Hongwen,SHU Haijian,et al.Mechanical behavior of sandstone containing double circular cavities under uniaxial compression[J].Chinese Journal of Geotechnical Engineering,2015,37(6):1 047–1 056.(in Chinese))
[23]朱谭谭,靖洪文,苏海健,等.孔洞–裂隙组合型缺陷砂岩力学特性试验研究[J].煤炭学报,2015,40(7):1 518–1 525.(ZHU Tantan,JING Hongwen,SU Haijian,et al.Experimental investigation on mechanical behavior of sandstone with coupling effects under uniaxial compression[J].Journal of China Coal Society,2015,40(7):1 518–1 525.(in Chinese))
[24]杨圣奇,吕朝辉,渠涛.含单个孔洞大理岩裂纹扩展细观试验和模拟[J].中国矿业大学学报,2009,38(6):774–781.(YANG Shengqi,LU Chaohui,QU Tao.Investigations of crack expansion in marble having a single pre-existing hole:experiment and simulations[J].Journal of China University of Mining and Technology,2009,38(6):774–781.(in Chinese))
[25]杨圣奇,刘相如,李玉寿.单轴压缩下含孔洞裂隙砂岩力学特性试验分析[J].岩石力学与工程学报,2012,31(增2):3 539–3 546.(YANG Shengqi,LIU Xiangru,LI Yushou.Experimental analysis of mechanical behavior of sandstone containing hole and fissure under uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(Supp.2):3 539–3 546.(in Chinese))
[26]李地元,李夕兵,李春林,等.单轴压缩下含预制孔洞板状花岗岩试样力学响应的试验和数值研究[J].岩石力学与工程学报,2011,30(6):1 198–1 206.(LI Diyuan,LI Xibing,LI Chunlin,et al.Experimental and numerical studies of mechanical response of plate-shape granite samples containing prefabricated holes under uniaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(6):1 198–1 206.(in Chinese))
[27]段进超,唐春安,常旭,等.单轴压缩下含孔脆性材料的力学行为研究[J].岩土力学,2006,27(8):1 416–1 420.(DUAN Jinchao,TANG Chun?an,CHANG Xu,et al.Study on mechanics behavior of containing holes in brittle material subjected to uniaxial compression[J].Rock and Soil Mechanics,2006,27(8):1 416–1 420.(in Chinese))
[28]杜明瑞,靖洪文,苏海健,等.孔洞形状对砂岩强度及破坏特征的影响[J].工程力学,2016,33(7):190–196.(DU Mingrui,JING Hongwen,SU Haijian,et al.Effects of holes?geometrical shape on strength and failure characteristics of sandstone sample containing a single hole[J].Engineering Mechanics,2016,33(7):190–196.(in Chinese))
[29]杜明瑞,靖洪文,苏海健,等.含预制椭圆形孔洞砂岩强度及破坏特征试验研究[J].中国矿业大学学报,2016,45(6):1 164–1 171.(DU Mingrui,JING Hongwen,SU Haijian,et al.Experimental study of strength and failure characteristics of sandstone containing prefabricated elliptical hole[J].Journal of China University of Mining and Technology,2016,45(6):1 164–1 171.(in Chinese))
[30]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.
[31]YANG S Q,JING H W,XU T.Mechanical behavior and failure analysis of brittle sandstone specimens containing combined flaws under uniaxial compression[J].Journal of Central South University,2014,21(5):2 059–2 073.
[32]WONG R H C,LIN P,TANG C A.Experimental and numerical study on splitting failure of brittle solids containing single pore under uniaxial compression[J].Mechanics of Materials,2006,38(1):142–159.
[33]WANG S Y,SLOAN S W,TANG C A.Three-dimensional numerical investigations of the failure mechanism of a rock disc with a central or eccentric hole[J].Rock Mechanics and Rock Engineering,2014,47(6):2 117–2 137.
[34]CAO W G,ZHAO H,LI X,et al.Statistical damage model with strain softening and hardening for rocks under the influence of voids and volume changes[J].Canadian Geotechnical Journal,2010,47(8):857–871.
[35]CARTER B J,YUA E Z L Y.Tensile fracture from circular cavities loaded in compression[J].International Journal of Fracture,1992,57(3):221–236.
[36]张哲,唐春安,于庆磊,等.侧压系数对圆孔周边松动区破坏模式影响的数值试验研究[J].岩土力学,2009,30(2):413–418.(ZHANG Zhe,TANG Chun?an,YU Qinglei,et al.Numerical simulation on influence coefficient of lateral pressure on broken zone of circular aperture[J].Rock and Soil Mechanics,2009,30(2):413–418.(in Chinese))
[37]HAAS C J.Shear resistance of rock bolts[M].Rolla:University of Missouri,1976:260.
[38]YOSHINAKA R,S S,T S.Experimental study of the bolt reinforcement in discontinuous rock[C]//Proceedings of the 6th IRSM Congress.Montreal:International Society for Rock Mechanics,1987:1 329–1 332.
[39]SPANG K,EGGER P.Action of fully-grouted bolt in jointed rock and factors of influence[J].Rock Mechanics and Rock Engineerin,1990,23(3):201–229.
[40]KIM H J,HU J W,HWANG W S.Cyclic testing for structural detail improvement of CFT column-foundation connections[J].Sustainability,2015,7(5):5 260–5 281.
[41]FERRERO A M.The shear strength of reinforced rock joints[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics,1995,32(6):595–605.
[42]PELLET F,EGGER P.Analytical model for the mechanical behaviour of bolted rock joints subjected to shearing[J].Rock Mechanics and Rock Engineering,1996,29(2):73–97.
[43]陈璐,谭云亮,臧传伟,等.加锚岩石力学性质及破坏特征试验研究[J].岩土力学,2014,35(2):413–422.(CHEN Lu,TAN Yunliang,ZANG Chuanwei,et al.Test study of mechanical properties and failure characteristics of anchored rock[J].Rock and Soil Mechanics,2014,35(2):413–422.(in Chinese))
[44]陈璐,臧传伟,于凤海,等.加锚岩石抗弯特性试验研究[J].岩土力学,2014,35(12):3 451–3 459.(CHEN Lu,ZANG Chuanwei,YU Fenghai,et al.Experimental study of flexural behavior of anchored rock[J].Rock and Soil Mechanics,2014,35(12):3 451–3 459.(in Chinese))
[45]汪小刚,周纪军,贾志欣,等.加锚节理面的抗剪试验研究[J].岩土力学,2016,37(增2):250–256.(WANG Xiaogang,ZHOU Jijun,JIA Zhixin,et al.Shear tests on bolted joint planes[J].Rock and Soil Mechanics,2016,37(Supp.2):250–256.(in Chinese))
[46]王平,冯涛,朱永建,等.加锚预制裂隙类岩体锚固机制试验研究及其数值模拟[J].岩土力学,2016,37(3):793–801.(WANG Ping,FENG Tao,ZHU Yongjian,et al.Experimental study and numerical simulation of anchoring mechanism of anchored rocklike material with prefabricated fracture[J].Rock and Soil Mechanics,2016,37(3):793–801.(in Chinese))
[47]RYBACKI E,MEIER T,DRESEN G.What controls the mechanical properties of shale rocks?—Part II:Brittleness[J].Journal of Petroleum Science and Engineering,2016,144(1):39–58.
[48]衡帅,杨春和,张保平,等.页岩各向异性特征的试验研究[J].岩土力学,2015,36(3):609–616.(HENG Shuai,YANG Chunhe,ZHANG Baoping,et al.Experimental research on anisotropic properties of shale[J].Rock and Soil Mechanics,2015,26(3):609–616.(in Chinese))
[49]RYBACKI E,REINICKE A,MEIER T,et al.What controls the mechanical properties of shale rocks?—Part I:Strength and Young?s modulus[J].Journal of Petroleum Science and Engineering,2015,135(1):702–722.
[50]CHO J W,KIM H,JEON S,et al.Deformation and strength anisotropy of Asan gneiss,Boryeong shale,and Yeoncheon schist[J].International Journal of Rock Mechanics and Mining Sciences,2012,50:158–169.
[51]LI D,ZHU Q,ZHOU Z,et al.Fracture analysis of marble specimens with a hole under uniaxial compression by digital image correlation[J].Engineering Fracture Mechanics,2017,183(1):109–124.
[52]RAYNAUD S,FABRE D,MAZEROLLE F,et al.Analysis of the internal structure of rocks and characterization of mechanical deformation by a non-destructive method:X-ray tomodensitometry[J].Tectonophysics,1989,159(1):149–159.
[53]KAWAKATA H,CHO A,YANAGIDANI T,et al.The observations of faulting in westerly granite under triaxial compression by X-ray CT scan[J].International Journal of Rock Mechanics and Mining Sciences,1997,34(3):151–162.
[54]FENG X T,CHEN S,ZHOU H.Real-time computerized tomography(CT)experiments on sandstone damage evolution during triaxial compression with chemical corrosion[J].International Journal of Rock Mechanics and Mining Sciences,2004,41(2):181–192.
[55]RAYNAUD S,NGAN-TILLARD D,DESRUES J,et al.Brittleto-ductile transition in Beaucaire marl from triaxial tests under the CT-scanner[J].International Journal of Rock Mechanics and Mining Sciences,2008,45(5):653–671.
[56]朱浮声,郑雨天.全长粘结式锚杆的加固作用分析[J].岩石力学与工程学报,1996,15(4):333–337.(ZHU Fusheng,ZHENG Yutian.Support action analysis of tensioned and grouted bolts[J].Chinese Journal of Rock Mechanics and Engineering,1996,15(4):333–337.(in Chinese))
[57]王刚,蒋宇静,李为腾,等.弱胶结软岩大变形破坏控制理论与技术[M].北京:科学出版社,2016:82–90.(WANG Gang,JIANG Yujing,LI Weiteng,et al.Control theory and technology of large deformation failure of weak cementation soft rock[M].Beijing:Science Press,2016:82–90.(in Chinese))请补充引用的页码
[58]侯朝炯,勾攀峰.巷道锚杆支护围岩强度强化机理研究[J].岩石力学与工程学报,2000,19(3):342–345.(HOU Chaojiong,GOU Panfeng.Mechanism study on strength enhancement for the rocks surrounding roadway supported by bolt[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(3):342–345.(in Chinese))
[59]CAI Y,JIANG Y,DJAMALUDDIN I,et al.An analytical model considering interaction behavior of grouted rock bolts for convergence-confinement method in tunneling design[J].International Journal of Rock Mechanics and Mining Sciences,2015,76:112–126.