辽西花岗岩水–岩耦合力学特性试验研究
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摘要
为了研究水–岩耦合作用对辽西花岗岩力学性质的影响,采用MTS–815岩石力学试验系统,通过对花岗岩试样施加不同的围压和孔隙水压力,对其变形破坏过程进行试验研究,分析水–岩耦合作用下辽西花岗岩的有效峰值强度、扩容现象、残余强度、峰后强度及其参数的演化规律。研究结果表明,有效峰值强度折减系数随孔隙水压力增大近似呈线性增长,但变化斜率随着围压增大而逐渐减小。在围压较小时孔隙水压对有效强度折减系数有明显的影响,在围压较大而孔隙水压较小时,施加应力压缩孔隙喉道抑制了孔隙水压对试样的作用。扩容起点是致密岩体水岩耦合作用增强的特征点,围压使得试样的扩容起点发生滞后,而孔隙水压力使得扩容起点提前发生,扩容现象与水岩耦合作用相互促进。水–岩耦合作用下试样的残余强度为对应状态峰值强度的21%~35%,Hoek-Brown常数随着围压的增大呈非线性增长,其值为3.5~5.0。峰后段试样的似内摩擦角变化不大,似黏聚力随着应变软化参数的增加有逐渐减小的趋势,而相同应变软化参数对应的似黏聚力则随着孔隙水压力的增大而减小,且似黏聚力、孔隙水压和应变软化参数间的关系可用3次样条曲面进行描述。
In order to study the influence of water on the mechanical properties of granite from Western Liaoning,the deformation and fracture of the granite were investigated with the mechanical test system of rock MTS–815.The effective peak intensity, volumetric dilation, residual strength,post-peak intensity and parameters of the granite were analyzed under different confining pressures and pore water pressures. The reduction factor of the effective peak strength was found to increase linearly with the increasing of pore water pressure and the slope of the linear relationship was reduced gradually with the increasing of confining pressure. When the confining pressure was smaller, the influence of the pore water pressure to the reduction factor of the effective peak strength was clearly notable. When the confining pressure was larger and the pore water pressure was smaller,the effect of pore water pressure was suppressed because the pore throat was compressed under the condition of applied stress. The starting point of volume expansion was found to be the characteristic point of enhanced water effect in dense rock.The confining pressure delayed the occurrence of expansion, while the pore water pressure promoted the occurrence of expansion. The volumetric dilation and water effect promoted each other. The residual strengthunder water effect is about 21% to 35% of the peak strength without water effect. Hoek-Brown constant increased nonlinearly with the increasing of confining pressure, and its value was between 3.5 and 5.0. At the post-peak stage of stress-stain curve, the change of pseudo internal friction angle was found to be small. The pseudo cohesion decreased with the increasing of strain softening coefficient,and it decreased with the increasing of pore water pressure when the strain softening coefficient was the same. The cubic spline surface was used to describe the relationship among the generalized cohesion,pore water pressure and strain softening parameter.
In order to study the influence of water on the mechanical properties of granite from Western Liaoning,the deformation and fracture of the granite were investigated with the mechanical test system of rock MTS–815.The effective peak intensity, volumetric dilation, residual strength,post-peak intensity and parameters of the granite were analyzed under different confining pressures and pore water pressures. The reduction factor of the effective peak strength was found to increase linearly with the increasing of pore water pressure and the slope of the linear relationship was reduced gradually with the increasing of confining pressure. When the confining pressure was smaller, the influence of the pore water pressure to the reduction factor of the effective peak strength was clearly notable. When the confining pressure was larger and the pore water pressure was smaller,the effect of pore water pressure was suppressed because the pore throat was compressed under the condition of applied stress. The starting point of volume expansion was found to be the characteristic point of enhanced water effect in dense rock.The confining pressure delayed the occurrence of expansion, while the pore water pressure promoted the occurrence of expansion. The volumetric dilation and water effect promoted each other. The residual strengthunder water effect is about 21% to 35% of the peak strength without water effect. Hoek-Brown constant increased nonlinearly with the increasing of confining pressure, and its value was between 3.5 and 5.0. At the post-peak stage of stress-stain curve, the change of pseudo internal friction angle was found to be small. The pseudo cohesion decreased with the increasing of strain softening coefficient,and it decreased with the increasing of pore water pressure when the strain softening coefficient was the same. The cubic spline surface was used to describe the relationship among the generalized cohesion,pore water pressure and strain softening parameter.
引文
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[2]BIOT M A.Generalized theory of three-dimensional consolidation[J].Journal of Applied Physics,1941,12(2):155–164.
[3]卢应发,孙慧,李建林,等.水–岩石相互作用力学参数的探讨[J].岩石力学与工程学报,2009,28(10):1 995–2 005.(LU Yingfa,SUN Hui,LI Jianlin,et al.Investigation on mechanical parameters of water-rock interaction[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(10):1 995–2 005.(in Chinese))
[4]朱珍德,张爱军,徐卫亚.脆性岩石全应力–应变过程渗流特性试验研究[J].岩土力学,2002,23(5):555–559.(ZHU Zhende,ZHANG Aijun,XU Weiya.Experimental research on complete stress-strain process seepage characteristics of brittle rock[J].Rock and Soil Mechanics,2002,23(5):555–559.(in Chinese))
[5]XIAO Y X,LEE C F,WANG S J.Assessment of an equivalent porous medium for coupled stress and fluid flow in fractured rock[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(7):871–881.
[6]王连国,缪协兴.岩石渗透率与应力、应变关系的尖点突变模型[J].岩石力学与工程学报,2005,24(23):4 210–4 214.(WANG Lianguo,MIAO Xiexing.Cusp catastrophe model of relations among permeability,stress and strain of rocks[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(23):4 210–4 214.(in Chinese))
[7]陈卫忠,杨建平,杨家岭,等.裂隙岩体应力渗流耦合模型在压力隧洞工程中的应用[J].岩石力学与工程学报,2006,25(12):2 384–2 391.(CHEN Weizhong,YANG Jianping,YANG Jialing,et al.Hydromechanical coupled model of jointed rock mass and its application to pressure tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(12):2 384–2 391.(in Chinese))
[8]李佳伟,徐进,王璐,等.砂板岩岩体力学特性的水岩耦合试验研究[J].岩石力学与工程学报,2013,32(3):599–604.(LI Jiawei,XU Jin,WANG Lu,et al.Water-rock coupling tests on mechanical properties of sandy slate rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):599–604.(in Chinese))
[9]SCHULZE O,POPP T,KERN H.Development of damage and permeability in deforming rock salt[J].Engineering Geology,2001,61(2/3):163–180.
[10]刘新荣,傅晏,王永新,等.(库)水–岩作用下砂岩抗剪强度劣化规律的试验研究[J].岩土工程学报,2008,30(9):1 298–1 302.(LIU Xinrong,FU Yan,WANG Yongxin,et al.Deterioration rules of shear strength of sand rock under water-rock interaction of reservoir[J].Chinese Journal of Geotechnical Engineering,2008,30(9):1 298–1 302.(in Chinese))
[11]郤保平,赵阳升,万志军,等.热力耦合作用下花岗岩流变模型的本构关系研究[J].岩石力学与工程学报,2009,28(5):956–967.(XI Baoping,ZHAO Yangsheng,WAN Zhijun,et al.Study of constitutive equation of granite rheological model with thermo-mechanical coupling effects[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(5):956–967.(in Chinese))
[12]申林方,冯夏庭,潘鹏志,等.单裂隙花岗岩在应力–渗流–化学耦合作用下的试验研究[J].岩石力学与工程学报,2010,29(7):1 379–1 388.(SHEN Linfang,FENG Xiating,PAN Pengzhi,et al.Experimental research on mechano-hydro-chemical coupling of granite with single fracture[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(7):1 379–1 388.(in Chinese))
[13]张志镇,高峰,徐小丽.花岗岩力学特性的温度效应试验研究[J].岩土力学,2011,32(8):2 346–2 352.(ZHANG Zhizhen,GAO Feng,XU Xiaoli.Experimental study of temperature effect of mechanical properties of granite[J].Rock and Soil Mechanics,2011,32(8):2 346–2 352.(in Chinese))
[14]刘建军,刘先贵.有效压力对低渗透多孔介质孔隙度、渗透率的影响[J].地质力学学报,2001,7(1):41–44.(LIU Jianjun,LIU Xiangui.The effect of effective pressure on porosity and permeability of low permeability porous media[J].Journal of Geomechanics,2001,7(1):41–44.(in Chinese))
[15]YUAN S C,HARRISON J P.Development of a hydro-mechnical local degradation approach and its application to modelling fluid flow during progressive fracturing of heterogeneous rocks[J].International Journal of Rock Mechanics and Ming Sciences,2005,42(8):961–984.
[16]贺玉龙,杨立中.温度和有效应力对砂岩渗透率的影响机制研究[J].岩石力学与工程学报,2005,24(14):2 420–2 427.(HE Yulong,YANG Lizhong.Mechanism of effects of temperature and effective stress on permeability of sand rock[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(14):2 420–2 427.(in Chinese))
[17]李根,唐春安,李连崇.水岩耦合变形破坏过程及机理研究进展[J].力学进展,2012,42(5):593–619.(LI Gen,TANG Chun?an,LI Lianchong.Advance in rock deformation and failure process under water-rock coupling[J].Advances in Mechanics,2012,42(5):593–619.(in Chinese))
[18]白国良,梁冰,李树志.采动影响下等效连续介质水岩耦合数学模型及应用[J].煤炭学报,2009,34(4):461–465.(BAI Guoliang,LIANG Bing,LI Shuzhi.An equivalent porous media water-rock coupling model impacted by coal mining and its application[J].Journal of China Coal Society,2009,34(4):461–465.(in Chinese))
[19]乔丽苹,王者超,李术才.基于Tight gas致密砂岩储层渗透率的有效应力特性研究[J].岩石力学与工程学报,2011,30(3):599–604.(QIAO Liping,WANG Zhechao,LI Shucai.Effective stress law for permeability of Tight gas reservoir sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(3):599–604.(in Chinese))
[20]BERNABE Y.The effective pressure law for permeability in Chelmsford granite and Barre granite[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1986,23(3):267–275.
[21]丁艳艳,李闽,肖文联.围压对低渗砂岩渗透率有效应力系数的影响[J].地球物理学进展,2012,27(2):696–701.(DING Yanyan,LI Min,XIAO Wenlian.The effect of confining pressure on effective pressure coefficient for permeability in low-permeability sandstones[J].Progress in Geophys,2012,27(2):696–701.(in Chinese))
[22]李传亮,孔祥言,杜志敏,等.多孔介质的流变模型研究[J].力学学报,2003,35(2):230–234.(LI Chuanliang,KONG Xiangyan,DU Zhimin,et al.A study on the rheological model of porous media[J].Acta Mechanica Sinica,2003,35(2):230–234.(in Chinese))
[23]ALKAN H,CINAR Y,PUSCH G.Rock salt dilatancy boundary from combined acoustic emission and triaxial compression tests[J].International Journal of Rock Mechnacis and Mining Sciences,2007,44(1):108–119.
[24]HOEK E,BROWN E T.Underground excavations in rock[M].London:Institution of Mining and Metallurgy,1980:23–25.
[25]陈庆敏,张农,赵海云,等.岩石残余强度与变形特性的试验研究[J].中国矿业大学学报,1997,26(3):42–45.(CHEN Qingmin,ZHANG Nong,ZHAO Yunhai,et al.Experimental research on the residual strength and deformation of rock[J].Journal of China University of Mining and Technology,1997,26(3):42–45.(in Chinese))
[26]陆银龙,王连国,杨峰,等.软弱岩石峰后应变软化力学特性研究[J].岩石力学与工程学报,2010,29(3):640–648.(LU Yinlong,WANG Lianguo,YANG Feng,et al.Post-peak strain softening mechanical properties of weak rock[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(3):640–648.(in Chinese))
[2]BIOT M A.Generalized theory of three-dimensional consolidation[J].Journal of Applied Physics,1941,12(2):155–164.
[3]卢应发,孙慧,李建林,等.水–岩石相互作用力学参数的探讨[J].岩石力学与工程学报,2009,28(10):1 995–2 005.(LU Yingfa,SUN Hui,LI Jianlin,et al.Investigation on mechanical parameters of water-rock interaction[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(10):1 995–2 005.(in Chinese))
[4]朱珍德,张爱军,徐卫亚.脆性岩石全应力–应变过程渗流特性试验研究[J].岩土力学,2002,23(5):555–559.(ZHU Zhende,ZHANG Aijun,XU Weiya.Experimental research on complete stress-strain process seepage characteristics of brittle rock[J].Rock and Soil Mechanics,2002,23(5):555–559.(in Chinese))
[5]XIAO Y X,LEE C F,WANG S J.Assessment of an equivalent porous medium for coupled stress and fluid flow in fractured rock[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(7):871–881.
[6]王连国,缪协兴.岩石渗透率与应力、应变关系的尖点突变模型[J].岩石力学与工程学报,2005,24(23):4 210–4 214.(WANG Lianguo,MIAO Xiexing.Cusp catastrophe model of relations among permeability,stress and strain of rocks[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(23):4 210–4 214.(in Chinese))
[7]陈卫忠,杨建平,杨家岭,等.裂隙岩体应力渗流耦合模型在压力隧洞工程中的应用[J].岩石力学与工程学报,2006,25(12):2 384–2 391.(CHEN Weizhong,YANG Jianping,YANG Jialing,et al.Hydromechanical coupled model of jointed rock mass and its application to pressure tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(12):2 384–2 391.(in Chinese))
[8]李佳伟,徐进,王璐,等.砂板岩岩体力学特性的水岩耦合试验研究[J].岩石力学与工程学报,2013,32(3):599–604.(LI Jiawei,XU Jin,WANG Lu,et al.Water-rock coupling tests on mechanical properties of sandy slate rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(3):599–604.(in Chinese))
[9]SCHULZE O,POPP T,KERN H.Development of damage and permeability in deforming rock salt[J].Engineering Geology,2001,61(2/3):163–180.
[10]刘新荣,傅晏,王永新,等.(库)水–岩作用下砂岩抗剪强度劣化规律的试验研究[J].岩土工程学报,2008,30(9):1 298–1 302.(LIU Xinrong,FU Yan,WANG Yongxin,et al.Deterioration rules of shear strength of sand rock under water-rock interaction of reservoir[J].Chinese Journal of Geotechnical Engineering,2008,30(9):1 298–1 302.(in Chinese))
[11]郤保平,赵阳升,万志军,等.热力耦合作用下花岗岩流变模型的本构关系研究[J].岩石力学与工程学报,2009,28(5):956–967.(XI Baoping,ZHAO Yangsheng,WAN Zhijun,et al.Study of constitutive equation of granite rheological model with thermo-mechanical coupling effects[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(5):956–967.(in Chinese))
[12]申林方,冯夏庭,潘鹏志,等.单裂隙花岗岩在应力–渗流–化学耦合作用下的试验研究[J].岩石力学与工程学报,2010,29(7):1 379–1 388.(SHEN Linfang,FENG Xiating,PAN Pengzhi,et al.Experimental research on mechano-hydro-chemical coupling of granite with single fracture[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(7):1 379–1 388.(in Chinese))
[13]张志镇,高峰,徐小丽.花岗岩力学特性的温度效应试验研究[J].岩土力学,2011,32(8):2 346–2 352.(ZHANG Zhizhen,GAO Feng,XU Xiaoli.Experimental study of temperature effect of mechanical properties of granite[J].Rock and Soil Mechanics,2011,32(8):2 346–2 352.(in Chinese))
[14]刘建军,刘先贵.有效压力对低渗透多孔介质孔隙度、渗透率的影响[J].地质力学学报,2001,7(1):41–44.(LIU Jianjun,LIU Xiangui.The effect of effective pressure on porosity and permeability of low permeability porous media[J].Journal of Geomechanics,2001,7(1):41–44.(in Chinese))
[15]YUAN S C,HARRISON J P.Development of a hydro-mechnical local degradation approach and its application to modelling fluid flow during progressive fracturing of heterogeneous rocks[J].International Journal of Rock Mechanics and Ming Sciences,2005,42(8):961–984.
[16]贺玉龙,杨立中.温度和有效应力对砂岩渗透率的影响机制研究[J].岩石力学与工程学报,2005,24(14):2 420–2 427.(HE Yulong,YANG Lizhong.Mechanism of effects of temperature and effective stress on permeability of sand rock[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(14):2 420–2 427.(in Chinese))
[17]李根,唐春安,李连崇.水岩耦合变形破坏过程及机理研究进展[J].力学进展,2012,42(5):593–619.(LI Gen,TANG Chun?an,LI Lianchong.Advance in rock deformation and failure process under water-rock coupling[J].Advances in Mechanics,2012,42(5):593–619.(in Chinese))
[18]白国良,梁冰,李树志.采动影响下等效连续介质水岩耦合数学模型及应用[J].煤炭学报,2009,34(4):461–465.(BAI Guoliang,LIANG Bing,LI Shuzhi.An equivalent porous media water-rock coupling model impacted by coal mining and its application[J].Journal of China Coal Society,2009,34(4):461–465.(in Chinese))
[19]乔丽苹,王者超,李术才.基于Tight gas致密砂岩储层渗透率的有效应力特性研究[J].岩石力学与工程学报,2011,30(3):599–604.(QIAO Liping,WANG Zhechao,LI Shucai.Effective stress law for permeability of Tight gas reservoir sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(3):599–604.(in Chinese))
[20]BERNABE Y.The effective pressure law for permeability in Chelmsford granite and Barre granite[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1986,23(3):267–275.
[21]丁艳艳,李闽,肖文联.围压对低渗砂岩渗透率有效应力系数的影响[J].地球物理学进展,2012,27(2):696–701.(DING Yanyan,LI Min,XIAO Wenlian.The effect of confining pressure on effective pressure coefficient for permeability in low-permeability sandstones[J].Progress in Geophys,2012,27(2):696–701.(in Chinese))
[22]李传亮,孔祥言,杜志敏,等.多孔介质的流变模型研究[J].力学学报,2003,35(2):230–234.(LI Chuanliang,KONG Xiangyan,DU Zhimin,et al.A study on the rheological model of porous media[J].Acta Mechanica Sinica,2003,35(2):230–234.(in Chinese))
[23]ALKAN H,CINAR Y,PUSCH G.Rock salt dilatancy boundary from combined acoustic emission and triaxial compression tests[J].International Journal of Rock Mechnacis and Mining Sciences,2007,44(1):108–119.
[24]HOEK E,BROWN E T.Underground excavations in rock[M].London:Institution of Mining and Metallurgy,1980:23–25.
[25]陈庆敏,张农,赵海云,等.岩石残余强度与变形特性的试验研究[J].中国矿业大学学报,1997,26(3):42–45.(CHEN Qingmin,ZHANG Nong,ZHAO Yunhai,et al.Experimental research on the residual strength and deformation of rock[J].Journal of China University of Mining and Technology,1997,26(3):42–45.(in Chinese))
[26]陆银龙,王连国,杨峰,等.软弱岩石峰后应变软化力学特性研究[J].岩石力学与工程学报,2010,29(3):640–648.(LU Yinlong,WANG Lianguo,YANG Feng,et al.Post-peak strain softening mechanical properties of weak rock[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(3):640–648.(in Chinese))