应力–渗流耦合下砂岩力学行为与渗透特性试验研究
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摘要
采用全自动三轴渗流实验系统,进行无水与排水条件下砂岩应力–渗流耦合试验,得到砂岩变形全过程应力–应变及渗透率演化曲线,较好地表征了应力–渗流耦合下砂岩力学行为与渗透率演化响应特征,同时获得了应力–渗流耦合下砂岩的变形、强度及渗透率演化规律。研究结果表明:(1)砂岩峰值强度随着围压增大而不断增大,围压效应显著;无水条件下,砂岩峰值强度对应的轴向应变变化规律与强度演化特征呈现出明显的对应关系。其轴向变形与围压的关系较好地符合指数函数非线性增长模型,而排水条件下的砂岩轴向变形与有效围压的关系较好地符合线性衰减模型;(2)砂岩峰前渗透率呈现出缓慢降低→平稳发展→急剧增加的三阶段演化规律,与砂岩峰前应力–应变曲线初始微裂纹压密、线弹性变形及新生裂纹扩展阶段三阶段变形具有对应关系;(3)不同工况下的砂岩变形全过程渗透率呈现出降低→急剧增加→稳定发展或略微增大的三阶段演化规律,与砂岩变形全过程体积压缩→体积快速膨胀→体积缓慢膨胀三阶段变形具有对应关系。研究结论可为煤矿突水事故防治及巷道围岩稳定控制提供一定的理论依据。
Stress-seepage coupling tests of sandstone under anhydrous and drainage conditions were conducted by using the automatic triaxial seepage experiment system. The stress-strain and permeability evolution curves of sandstone were obtained during the deformation process,which could better characterize the mechanical behaviors and permeability evolution response characteristics of sandstone under stress-seepage coupling,and the evolution law of deformation,strength and permeability of sandstone was investigated under stress-seepage coupling condition. The results show that the peak strength of sandstone increases with increasing the confining pressure,which shows that confining pressure effect is significant. The axial strain evolution law corresponding to the peak strength is in obvious accordance with the strength evolution characteristics under the anhydrous condition. The axial deformation of sandstone accords an exponential nonlinear growth relation with the confining pressure under the anhydrous condition,while the relationship between the axial deformation of sandstone and the effective confining pressure under drainage condition obeys a linear attenuation model. The pre-peak permeability of sandstone shows a"three-stage"evolution law of decreasing slowly firstly,then developing steadily and increasing sharply lastly,which respectively corresponds to the initial micro-crack compaction stage,linear elastic deformation stage and new crack propagation stage of the pre-peak stress-strain curve of sandstone. The permeability of sandstone also shows a three-stage evolution law including decreasing firstly and followed by increasing sharply and developing stably or increasing slightly under different working conditions,which also has a corresponding relationship with the volume compression stage,volume rapid expansion stage and volume slow expansion stage during the deformation process. The research conclusions can provide a theoretical basis for the prevention and control of water inrush accidents in coal mine and the stability controll of roadway surrounding rock.
Stress-seepage coupling tests of sandstone under anhydrous and drainage conditions were conducted by using the automatic triaxial seepage experiment system. The stress-strain and permeability evolution curves of sandstone were obtained during the deformation process,which could better characterize the mechanical behaviors and permeability evolution response characteristics of sandstone under stress-seepage coupling,and the evolution law of deformation,strength and permeability of sandstone was investigated under stress-seepage coupling condition. The results show that the peak strength of sandstone increases with increasing the confining pressure,which shows that confining pressure effect is significant. The axial strain evolution law corresponding to the peak strength is in obvious accordance with the strength evolution characteristics under the anhydrous condition. The axial deformation of sandstone accords an exponential nonlinear growth relation with the confining pressure under the anhydrous condition,while the relationship between the axial deformation of sandstone and the effective confining pressure under drainage condition obeys a linear attenuation model. The pre-peak permeability of sandstone shows a"three-stage"evolution law of decreasing slowly firstly,then developing steadily and increasing sharply lastly,which respectively corresponds to the initial micro-crack compaction stage,linear elastic deformation stage and new crack propagation stage of the pre-peak stress-strain curve of sandstone. The permeability of sandstone also shows a three-stage evolution law including decreasing firstly and followed by increasing sharply and developing stably or increasing slightly under different working conditions,which also has a corresponding relationship with the volume compression stage,volume rapid expansion stage and volume slow expansion stage during the deformation process. The research conclusions can provide a theoretical basis for the prevention and control of water inrush accidents in coal mine and the stability controll of roadway surrounding rock.
引文
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[9]王环玲,徐卫亚,杨圣奇.岩石变形破坏过程中渗透率演化规律的试验研究[J].岩土力学,2006,27(10):1 703-1 708.(WANGHuanling,XU Weiya,YANG Shengqi.Experimental investigation on permeability evolution law during course of deformation and failure of rock specimen[J].Rock and Soil Mechanics,2006,27(10):1 703-1 708.(in Chinese))
[10]JIANG T,SHAO J F,XU W Y,et al.Experimental investigation and micromechanical analysis of damage and permeability variation in brittle rocks[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(5):703-713.
[11]孔茜,王环玲,徐卫亚.循环加卸载作用下砂岩孔隙度与渗透率演化规律试验研究[J].岩土工程学报,2015,37(10):1 893-1 900.(KONG Qian,WANG Huanling,XU Weiya.Experimental study on permeability and porosity evolution of sandstone under cyclic loading and unloading[J].Chinese Journal of Geotechnical Engineering,2015,37(10):1 893-1 900.(in Chinese))
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[14]孙强,姜振泉,朱术云.北皂海域煤矿顶板软岩试样渗透性实验研究[J].岩土工程学报,2012,34(3):540-545.(SUN Qiang,JIANGZhenquan,ZHU Shuyun.Experimental study on permeability of soft rock of Beizao coal mine[J].Chinese Journal of Geotechnical Engineering,2012,34(3):540-545.(in Chinese))
[15]俞缙,李宏,陈旭,等.渗透压-应力耦合作用下砂岩渗透率与变形关联性三轴试验研究[J].岩石力学与工程学报,2013,32(6):1 203-1 213.(YU Jin,LI Hong,CHEN Xu,et al.Triaxial experimental study of associated permeability-deformation of sandstone under hydro-mechanical coupling[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(6):1 203-1 213.(in Chinese))
[16]范鹏贤,李颖,赵跃堂,等.红砂岩卸载破坏强度特征试验研究[J].岩石力学与工程学报,2018,37(4):852-861.(FAN Pengxian,LIYing,ZHAO Yuetang,et al.Experimental study on unloading failure strength of red sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(4):852-861.(in Chinese))
[17]尤明庆.常规三轴压缩的端部效应及花岗岩强度的研究[J].岩石力学与工程学报,2018,37(增1):3 160-3 168.(YOU Mingqing.Study on ends effect in conventional triaxial compression test and the strengths property of granites[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(Supp.1):3 160-3 168.(in Chinese))
[18]李宏国,朱大勇,姚华彦,等.温度作用后大理岩加-卸荷破裂特性试验研究[J].合肥工业大学学报:自然科学版,2016,39(1):109-114.(LI Hongguo,ZHU Dayong,YAO Huayan,et al.Loading and unloading test on fracture characteristics of marble after heating[J].Journal of Hefei University of Technology:Natural Science,2016,39(1):109-114.(in Chinese))
[19]侯鹏,高峰,张志镇,等.黑色页岩力学特性及气体压裂层理效应研究[J].岩石力学与工程学报,2016,35(4):670-681.(HOUPeng,GAO Feng,ZHANG Zhizhen,et al.Mechanical property and bedding inclination effect on gas fracturing of black shale[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(4):670-681.(in Chinese))
[20]WANG H L,XU W Y,SHAO J F.Experimental researches on hydro-mechanical properties of altered rock under confining pressures[J].Rock Mechanics and Rock Engineering,2014,47(2):485-493.
[21]夏英杰,李连崇,唐春安,等.储层砂岩破坏特征与脆性指数相关性影响的试验及数值研究[J].岩石力学与工程学报,2017,36(1):10-28.(XIA Yingjie,LI Lianchong,TANG Chun?an,et al.Experiment and numerical research on failure characteristic and brittleness index for reservoir sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(1):10-28.(in Chinese))
[22]王伟,陈曦,田振元,等.不同排水条件下砂岩应力渗流耦合试验研究[J].岩石力学与工程学报,2016,35(增2):3 540-3 551.(WANG Wei,CHEN Xi,TIAN Zhenyuan,et al.Experimental study on stress-seepage coupling properties of sandstone under different drainage conditions[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(Supp.2):3 540-3 551.(in Chinese))
[23]许江,杨红伟,彭守建,等.孔隙水压力-围压作用下砂岩力学特性的试验研究[J].岩石力学与工程学报,2010,29(8):1 618-1 623.(XU Jiang,YANG Hongwei,PENG Shoujian,et al.Experimental study of mechanical property of sandstone under pore water pressure and confining pressure[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(8):1 618-1 623.(in Chinese))
[2]杨天鸿,唐春安,谭志宏,等.岩体破坏突水模型研究现状及突水预测预报研究发展趋势[J].岩石力学与工程学报,2007,26(2):268-277.(YANG Tianhong,TANG Chun?an,TAN Zhihong,et al.State of the art of inrush models in rock mass failure[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(2):268-277.(in Chinese))
[3]WANG H L,XU W Y,ZUO J.Compact rock material gas permeability properties[J].Physica B,2014,449(6):10-18.
[4]XU P,YANG S Q.Permeability evolution of sandstone under short-term and long-term triaxial compression[J].International Journal of Rock Mechanics and Mining Sciences,2016,85(5):152-164.
[5]HU D W,ZHOU H,ZHANG F,et al.Evolution of poroelastic properties and permeability in damaged sandstone[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(6):962-973.
[6]WANG H L,XU W Y,JIA C J,et al.Experimental research on permeability evolution with microcrack development in sandstone under different fluid pressures[J].Journal of Geotechnical and Geoenvironmental Engineering,2016,142(6):1-9.
[7]李俊平,余志雄,周创兵,等.水力耦合下岩石的声发射特征试验研究[J].岩石力学与工程学报,2006,25(3):492-498.(LI Junping,YU Zhixiong,ZHOU Chuangbing,et al.Experimental study on acoustic emission charaistics of rock concerning hydromechanical coupling[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(3):492-498.(in Chinese))
[8]王小江,荣冠,周创兵.粗砂岩变形破坏过程中渗透性试验研究[J].岩石力学与工程学报,2012,31(增1):2 940-2 947.(WANGXiaojiang,RONG Guan,ZHOU Chuangbing.Permeability experimental study of gritstone in deformation and failure processes[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(Supp.1):2 940-2 947.(in Chinese))
[9]王环玲,徐卫亚,杨圣奇.岩石变形破坏过程中渗透率演化规律的试验研究[J].岩土力学,2006,27(10):1 703-1 708.(WANGHuanling,XU Weiya,YANG Shengqi.Experimental investigation on permeability evolution law during course of deformation and failure of rock specimen[J].Rock and Soil Mechanics,2006,27(10):1 703-1 708.(in Chinese))
[10]JIANG T,SHAO J F,XU W Y,et al.Experimental investigation and micromechanical analysis of damage and permeability variation in brittle rocks[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(5):703-713.
[11]孔茜,王环玲,徐卫亚.循环加卸载作用下砂岩孔隙度与渗透率演化规律试验研究[J].岩土工程学报,2015,37(10):1 893-1 900.(KONG Qian,WANG Huanling,XU Weiya.Experimental study on permeability and porosity evolution of sandstone under cyclic loading and unloading[J].Chinese Journal of Geotechnical Engineering,2015,37(10):1 893-1 900.(in Chinese))
[12]ZHANG J C,BAI M,ROEGIERS J C,et al.Experimental determination of stress-permeability relationship[C]//Proceedings of the 4th North American Rock Mechanics Symposium(NARMS 2000).Seattle,WA:[s.n.],2000:817-822.
[13]姜振泉,季梁军,左如松,等.岩石在伺服条件下的渗透性与应变、应力的关联性特征[J].岩石力学与工程学报,2002,21(10):1 442-1 446.(JIANG Zhenquan,JI Liangjun,ZUO Rusong,et al.Correlativity among rock permeability and strain,stress under servo-control condition[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(10):1 442-1 446.(in Chinese))
[14]孙强,姜振泉,朱术云.北皂海域煤矿顶板软岩试样渗透性实验研究[J].岩土工程学报,2012,34(3):540-545.(SUN Qiang,JIANGZhenquan,ZHU Shuyun.Experimental study on permeability of soft rock of Beizao coal mine[J].Chinese Journal of Geotechnical Engineering,2012,34(3):540-545.(in Chinese))
[15]俞缙,李宏,陈旭,等.渗透压-应力耦合作用下砂岩渗透率与变形关联性三轴试验研究[J].岩石力学与工程学报,2013,32(6):1 203-1 213.(YU Jin,LI Hong,CHEN Xu,et al.Triaxial experimental study of associated permeability-deformation of sandstone under hydro-mechanical coupling[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(6):1 203-1 213.(in Chinese))
[16]范鹏贤,李颖,赵跃堂,等.红砂岩卸载破坏强度特征试验研究[J].岩石力学与工程学报,2018,37(4):852-861.(FAN Pengxian,LIYing,ZHAO Yuetang,et al.Experimental study on unloading failure strength of red sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(4):852-861.(in Chinese))
[17]尤明庆.常规三轴压缩的端部效应及花岗岩强度的研究[J].岩石力学与工程学报,2018,37(增1):3 160-3 168.(YOU Mingqing.Study on ends effect in conventional triaxial compression test and the strengths property of granites[J].Chinese Journal of Rock Mechanics and Engineering,2018,37(Supp.1):3 160-3 168.(in Chinese))
[18]李宏国,朱大勇,姚华彦,等.温度作用后大理岩加-卸荷破裂特性试验研究[J].合肥工业大学学报:自然科学版,2016,39(1):109-114.(LI Hongguo,ZHU Dayong,YAO Huayan,et al.Loading and unloading test on fracture characteristics of marble after heating[J].Journal of Hefei University of Technology:Natural Science,2016,39(1):109-114.(in Chinese))
[19]侯鹏,高峰,张志镇,等.黑色页岩力学特性及气体压裂层理效应研究[J].岩石力学与工程学报,2016,35(4):670-681.(HOUPeng,GAO Feng,ZHANG Zhizhen,et al.Mechanical property and bedding inclination effect on gas fracturing of black shale[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(4):670-681.(in Chinese))
[20]WANG H L,XU W Y,SHAO J F.Experimental researches on hydro-mechanical properties of altered rock under confining pressures[J].Rock Mechanics and Rock Engineering,2014,47(2):485-493.
[21]夏英杰,李连崇,唐春安,等.储层砂岩破坏特征与脆性指数相关性影响的试验及数值研究[J].岩石力学与工程学报,2017,36(1):10-28.(XIA Yingjie,LI Lianchong,TANG Chun?an,et al.Experiment and numerical research on failure characteristic and brittleness index for reservoir sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(1):10-28.(in Chinese))
[22]王伟,陈曦,田振元,等.不同排水条件下砂岩应力渗流耦合试验研究[J].岩石力学与工程学报,2016,35(增2):3 540-3 551.(WANG Wei,CHEN Xi,TIAN Zhenyuan,et al.Experimental study on stress-seepage coupling properties of sandstone under different drainage conditions[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(Supp.2):3 540-3 551.(in Chinese))
[23]许江,杨红伟,彭守建,等.孔隙水压力-围压作用下砂岩力学特性的试验研究[J].岩石力学与工程学报,2010,29(8):1 618-1 623.(XU Jiang,YANG Hongwei,PENG Shoujian,et al.Experimental study of mechanical property of sandstone under pore water pressure and confining pressure[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(8):1 618-1 623.(in Chinese))