裂隙红砂岩冻胀力特性试验研究
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摘要
裂隙岩体冻胀现象在富水岩层冻结工程中普遍存在,冻胀力易使得岩体裂隙尖端应力集中而产生新的微裂纹,微裂纹扩展贯通导致岩体发生不同程度破坏。为揭示裂隙岩体冻融损伤演化机制,探究以冻胀力驱动下的岩体裂隙扩展规律,利用超薄型电阻式压力传感器、温度传感器、低温恒温箱组成的冻胀力测试系统对不同冻结速率、不同裂隙尺寸、倾角以及不同边界条件下红砂岩贯通裂隙中的冻胀力进行测试,分析了贯通裂隙中冻胀力演化规律、冻胀劣化机制以及冻胀破坏模式。结果表明:含贯通裂隙试样典型冻胀力演化过程分为初始冻结阶段、迅速上升阶段、卸荷阶段、维持阶段、消散阶段;冻胀作用使得贯通裂隙端部附近出现明显裂纹扩展现象,试样整体呈竖向张拉破坏;贯通裂隙最大冻胀力随隙宽呈单指数函数增长、与温度成线性正相关;冻结过程中,试样边界条件对裂隙冻胀力影响显著,刚性约束边界条件下最大冻胀力达到1. 27 MPa,融化过程中,不同边界条件对应不同冻胀力跌落现象;低温条件下贯通裂隙红砂岩冻胀力变化特征与冻胀过程中声发射能量变化规律一致,充分验证了冻胀力对贯通裂隙岩体的损伤劣化作用。研究成果可为裂隙岩体冻胀力理论计算与数值分析、冻融损伤机制、冰-岩耦合特性以及煤矿立井冻结壁设计等提供参考。
Frost heave phenomenon of fractured rock mass is widespread in the freezing engineering of water-rich rock strata.Frost heave force tends to cause stress concentration at the crack tip of rock mass to produce new micro-cracks.The propagation and penetration of micro-cracks lead to different degrees of damage of rock mass.In order to reveal the evolution mechanism of freeze-thaw damage in fractured rock mass and explore the law of fracture propagation in rock mass driven by frost heave force the frost heaving force in the connected crack of red sandstone is tested by a frost heave force testing system which consists of ultra-thin resistance pressure sensor,temperature sensor and low temperature and constant temperature box under different freezing rates,fracture sizes,dip angles and boundary conditions.Then the evolution law of frost heaving pressure,the mechanism of frost heaving deterioration and the failure mode of frost heaving are analyzed.The results show that the evolution process of typical frost heaving pressure of fractured red sandstone includes initial freezing stage,rapid freezing stage,unloading stage,maintenance stage and disappearing stage.The frost heaving effect causes obvious crack propagation behavior near the tip of crack,and the samples are vertical tension destruction.The maximum frost heaving pressure increases single exponentially with the width of gap and increases linearly with temperature.During the freezing process,the boundary condition of the sample has a significant influence on the frost heaving pressure of fracture,the maximum frost heaving force is 1.27 MPa under rigid confined boundary conditions.During the melting process,different boundary conditions correspond to different falling phenomena of frost heaving pressure.The characteristics of frost heaving pressure in red sandstone with penetrating fracture under low temperature is consistent with the law of AE energy change during the process of frost heave,and the damage and deterioration effect of frost heaving force on the fractured rock mass is fully verified.The research results can provide a reference for the theoretical calculation and numerical analysis of frost heaving pressure in fractured rock mass,the mechanism of freezing and thawing damage,the characteristics of ice-rock coupled and the design of the frozen wall of the coal mine.
Frost heave phenomenon of fractured rock mass is widespread in the freezing engineering of water-rich rock strata.Frost heave force tends to cause stress concentration at the crack tip of rock mass to produce new micro-cracks.The propagation and penetration of micro-cracks lead to different degrees of damage of rock mass.In order to reveal the evolution mechanism of freeze-thaw damage in fractured rock mass and explore the law of fracture propagation in rock mass driven by frost heave force the frost heaving force in the connected crack of red sandstone is tested by a frost heave force testing system which consists of ultra-thin resistance pressure sensor,temperature sensor and low temperature and constant temperature box under different freezing rates,fracture sizes,dip angles and boundary conditions.Then the evolution law of frost heaving pressure,the mechanism of frost heaving deterioration and the failure mode of frost heaving are analyzed.The results show that the evolution process of typical frost heaving pressure of fractured red sandstone includes initial freezing stage,rapid freezing stage,unloading stage,maintenance stage and disappearing stage.The frost heaving effect causes obvious crack propagation behavior near the tip of crack,and the samples are vertical tension destruction.The maximum frost heaving pressure increases single exponentially with the width of gap and increases linearly with temperature.During the freezing process,the boundary condition of the sample has a significant influence on the frost heaving pressure of fracture,the maximum frost heaving force is 1.27 MPa under rigid confined boundary conditions.During the melting process,different boundary conditions correspond to different falling phenomena of frost heaving pressure.The characteristics of frost heaving pressure in red sandstone with penetrating fracture under low temperature is consistent with the law of AE energy change during the process of frost heave,and the damage and deterioration effect of frost heaving force on the fractured rock mass is fully verified.The research results can provide a reference for the theoretical calculation and numerical analysis of frost heaving pressure in fractured rock mass,the mechanism of freezing and thawing damage,the characteristics of ice-rock coupled and the design of the frozen wall of the coal mine.
引文
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[8] DAVIDSON G P,NYE J F.A photoelastic study of ice pressure in rock cracks[J]. Cold Regions Science and Technology,1985,11(2):141-153.
[9] MATSUOKA N.Mechanisms of rock breakdown by frost action:An experimental approach[J]. Cold Regions Science and Technology,1990,17(3):253-270.
[10] MATSUOKA N.A laboratory simulation on freezing expansion of a fractured rock:Preliminary data[R].Tokyo:University of Tsukuba,1995:5-8.
[11] MATSUOKA N. Microgelivation versus macrogelivation:Towards bridging the gap between laboratory and field frost weathering[J].Permafrost and Periglacial Processes,2001,12(3):299-313.
[12] MATSUOKA N.Direct observation of frost wedging in alpine bedrock[J]. Earth Surface Processes and Landforms,2001,26(6):601-614.
[13] CHEN T C,YEUNG M R,MORI N. Effect of water saturation on deterioration of welded tuff due to freeze-thaw action[J].Cold Regions Science and Technology,2004,38(2):127-136.
[14] AROSIO D,LONGONI L,MAZZA F,et al.Freeze-thaw cycle and rockfall monitoring[M]. Berlin:Landslide Science and Practice,2013:385-390.
[15] TAN X,CHEN W,LIU H,et al. A unified model for frost heave pressure in the rock with a penny-shaped fracture during freezing[J].Cold Regions Science and Technology,2018,153:1-9.
[16] XIA C,LZ,LI Q,et al.Transversely isotropic frost heave of saturated rock under unidirectional freezing condition and induced frost heaving force in cold region tunnels[J].Cold Regions Science and Technology,2018,152:48-58.
[17]阎锡东,刘红岩,邢闯锋,等.基于微裂隙变形与扩展的岩石冻融损伤本构模型研究[J].岩土力学,2015,36(12):3489-3499.YAN Xidong,LIU Hongyan,XING Chuangfeng,et al. Constitutive model research on freezing-thawing damage of rock based on deformation and propagation of microcracks[J]. Rock and Soil Mechanics,2015,36(12):3489-3499.
[18]刘泉声,黄诗冰,康永水,等.裂隙冻胀压力及对岩体造成的劣化机制初步研究[J].岩土力学,2016,37(6):1530-1542.LIU Quansheng,HUANG Shibing,KANG Yongshui,et al. Preliminary study of frost heave pressure and its influence on crack and deterioration mechanisms of rock mass[J]. Rock and Soil Mechanics,2016,37(6):1530-1542.
[19] HUANG S,LIU Q,LIU Y,et al.Frost heaving and frost cracking of elliptical cavities(fractures)in low-permeability rock[J]. Engineering Geology,2018,234:1-10.
[20]黄诗冰,刘泉声,刘艳章,等.低温热力耦合下岩体椭圆孔(裂)隙中冻胀力与冻胀开裂特征研究[J].岩土工程学报,2018,40(3):459-467.HUANG Shibing,LIU Quansheng,LIU Yanzhang,et al. Frost heaving pressure and characteristics of frost cracking in ellipticalcavity(crack)of rock mass under coupled thermal-mechanical condition at low temperature[J]. Chinese Journal of Geotechnical Engineering,2018,40(3):459-467.
[2]单仁亮,白瑶,隋顺猛,等.淡水冰三轴压缩力学特性试验研究[J].应用基础与工程科学学报,2018,26(4):901-917.SHAN Renliang,BAI Yao,SUI Shunmeng,et al. Experimental research on mechanical characteristics of freshwater ice under triaxial compression[J].Journal of Basic Science and Engineering,2018,26(4):901-917.
[3]奚家米,杨更社,庞磊,等.低温冻结作用下砂质泥岩基本力学特性试验研究[J].煤炭学报,2014,39(7):1262-1268.XI Jiami,YANG Gengshe,PANG Lei,et al. Experimental study on basic mechanical behaviors of sandy mudstone under low freezing temperature[J]. Journal of China Coal Society,2014,39(7):1262-1268.
[4]杨昊,张晋勋,单仁亮,等.冻结饱水单裂隙岩体力学特性试验研究[J].岩土力学,2018,39(4):1245-1255.YANG Hao,ZHANG Jinxun,SHAN Renliang,et al. Experimental study on mechanical properties of frozen saturated single fractured rock mass[J].Rock and Soil Mechanics,2018,39(4):1245-1255.
[5]单仁亮,张蕾,杨昊,等.饱水红砂岩冻融特性试验研究[J].中国矿业大学学报,2016,45(5):923-929.SHAN Renliang,ZHANG Lei,YANG Hao,et al. Experimental study of freeze-thaw properties of saturated red sandstone[J]. Journal of China University of Mining and Technology,2016,45(5):923-929.
[6]黄诗冰,刘泉声,程爱平,等.低温岩体裂隙冻胀力与冻胀扩展试验初探[J].岩土力学,2018,39(1):78-84.HUANG Shibing,LIU Quansheng,CHENG Aiping,et al.Preliminary experimental study of frost heaving pressure in crack and frost heaving propagation in rock mass under low temperature[J]. Rock and Soil Mechanics,2018,39(1):78-84.
[7] THARP T M. Conditions for crack propagation by frost wedging[J].Geological Society of America Bulletin,1987,99(1):94-102.
[8] DAVIDSON G P,NYE J F.A photoelastic study of ice pressure in rock cracks[J]. Cold Regions Science and Technology,1985,11(2):141-153.
[9] MATSUOKA N.Mechanisms of rock breakdown by frost action:An experimental approach[J]. Cold Regions Science and Technology,1990,17(3):253-270.
[10] MATSUOKA N.A laboratory simulation on freezing expansion of a fractured rock:Preliminary data[R].Tokyo:University of Tsukuba,1995:5-8.
[11] MATSUOKA N. Microgelivation versus macrogelivation:Towards bridging the gap between laboratory and field frost weathering[J].Permafrost and Periglacial Processes,2001,12(3):299-313.
[12] MATSUOKA N.Direct observation of frost wedging in alpine bedrock[J]. Earth Surface Processes and Landforms,2001,26(6):601-614.
[13] CHEN T C,YEUNG M R,MORI N. Effect of water saturation on deterioration of welded tuff due to freeze-thaw action[J].Cold Regions Science and Technology,2004,38(2):127-136.
[14] AROSIO D,LONGONI L,MAZZA F,et al.Freeze-thaw cycle and rockfall monitoring[M]. Berlin:Landslide Science and Practice,2013:385-390.
[15] TAN X,CHEN W,LIU H,et al. A unified model for frost heave pressure in the rock with a penny-shaped fracture during freezing[J].Cold Regions Science and Technology,2018,153:1-9.
[16] XIA C,LZ,LI Q,et al.Transversely isotropic frost heave of saturated rock under unidirectional freezing condition and induced frost heaving force in cold region tunnels[J].Cold Regions Science and Technology,2018,152:48-58.
[17]阎锡东,刘红岩,邢闯锋,等.基于微裂隙变形与扩展的岩石冻融损伤本构模型研究[J].岩土力学,2015,36(12):3489-3499.YAN Xidong,LIU Hongyan,XING Chuangfeng,et al. Constitutive model research on freezing-thawing damage of rock based on deformation and propagation of microcracks[J]. Rock and Soil Mechanics,2015,36(12):3489-3499.
[18]刘泉声,黄诗冰,康永水,等.裂隙冻胀压力及对岩体造成的劣化机制初步研究[J].岩土力学,2016,37(6):1530-1542.LIU Quansheng,HUANG Shibing,KANG Yongshui,et al. Preliminary study of frost heave pressure and its influence on crack and deterioration mechanisms of rock mass[J]. Rock and Soil Mechanics,2016,37(6):1530-1542.
[19] HUANG S,LIU Q,LIU Y,et al.Frost heaving and frost cracking of elliptical cavities(fractures)in low-permeability rock[J]. Engineering Geology,2018,234:1-10.
[20]黄诗冰,刘泉声,刘艳章,等.低温热力耦合下岩体椭圆孔(裂)隙中冻胀力与冻胀开裂特征研究[J].岩土工程学报,2018,40(3):459-467.HUANG Shibing,LIU Quansheng,LIU Yanzhang,et al. Frost heaving pressure and characteristics of frost cracking in ellipticalcavity(crack)of rock mass under coupled thermal-mechanical condition at low temperature[J]. Chinese Journal of Geotechnical Engineering,2018,40(3):459-467.