基于热-水-力-损伤耦合数值模型的高地温水工高压隧洞围岩承载特性
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摘要
针对高地温水工高压隧洞围岩的力学行为特点,在考虑岩体的渗透系数、热传导系数随岩体损伤发生变化的基础上,基于多物理场耦合理论,提出一种考虑硬岩强度力学参数劣化的含损伤演化的热-水-力-损伤耦合模型,并给出了该模型的FLAC3D数值实现方法。通过与物理模型试验结果对比,验证了模型的可靠性,进而利用该模型推演了高地温水工高压隧洞的多物理场耦合演化过程,分析了不同影响因素下的承载特性。研究结果表明:隧洞充水运行后,高地温水工高压隧洞的多场耦合效应显著,尤其高地温梯度和高内水压力联合作用下产生的迭加拉应力对围岩的承载安全具有不利影响;温度梯度、内水压力以及岩体线膨胀系数越大,隧洞围岩的损伤程度与开裂深度越大;当隧洞横断面的侧压力系数趋向于1时,洞周出现的宏观裂缝较多,且出现方位不确定;当隧洞横断面侧压力系数小于1/3时,洞周出现的宏观裂缝相对较少,且主要出现在与初始地应力的最大主应力方向相平行的方向上。常规锚喷支护对高地温水工高压隧洞的加固效果不佳。
To reveal the mechanical behavior characteristics of surrounding rock of hydraulic tunnels under high temperature and hydraulic pressure conditions, this paper proposes a coupled thermo-hydro-mechanical-damage(THMD) model which considers change of hard rock strength parameters involving damage evolution based on multi-field coupling theory with permeability coefficient and heat transfer coefficient varying with rock damage. The implementation of THMD numerical simulation is conducted by the FLAC3 D software. The model is proved to be feasible by validation of a physical modeling test, and then the THMD model is employed to deduce the evolution process of multi-field coupling of hydraulic tunnels with high temperature and hydraulic pressure. The evolution process is used to analyze the load-bearing characteristics influenced by different factors. The multi-field coupling effects are very significant in hydraulic tunnels with high temperature and hydraulic pressure after water-filling operation. The complex tensile stress generated by combined load of high temperature gradient and hydraulic pressure contributes to adverse impacts on safe performance of surrounding rock. The damage and crack depth of surrounding rock are larger if the temperature gradient, hydraulic pressure and thermal expansion coefficient are larger. If the lateral pressure coefficient is close to 1, more cracks around the tunnel with random directions tend to form. If the lateral pressure coefficient is less than 1/3, fewer cracks appear around the tunnel and the directions of the cracks are mostly parallel to the direction of the maximum initial stress. The general bolt-shotcrete support does not have good performance in reinforcement of hydraulic tunnels.
To reveal the mechanical behavior characteristics of surrounding rock of hydraulic tunnels under high temperature and hydraulic pressure conditions, this paper proposes a coupled thermo-hydro-mechanical-damage(THMD) model which considers change of hard rock strength parameters involving damage evolution based on multi-field coupling theory with permeability coefficient and heat transfer coefficient varying with rock damage. The implementation of THMD numerical simulation is conducted by the FLAC3 D software. The model is proved to be feasible by validation of a physical modeling test, and then the THMD model is employed to deduce the evolution process of multi-field coupling of hydraulic tunnels with high temperature and hydraulic pressure. The evolution process is used to analyze the load-bearing characteristics influenced by different factors. The multi-field coupling effects are very significant in hydraulic tunnels with high temperature and hydraulic pressure after water-filling operation. The complex tensile stress generated by combined load of high temperature gradient and hydraulic pressure contributes to adverse impacts on safe performance of surrounding rock. The damage and crack depth of surrounding rock are larger if the temperature gradient, hydraulic pressure and thermal expansion coefficient are larger. If the lateral pressure coefficient is close to 1, more cracks around the tunnel with random directions tend to form. If the lateral pressure coefficient is less than 1/3, fewer cracks appear around the tunnel and the directions of the cracks are mostly parallel to the direction of the maximum initial stress. The general bolt-shotcrete support does not have good performance in reinforcement of hydraulic tunnels.
引文
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[8]伍鹤皋,尚斌,苏凯.高压隧洞透水衬砌结构研究[J].武汉大学学报(工学版),2012,44(3):321-325.WU He-gao,SHANG Bin,SU Kai.Research of permeable lining structure for high pressure tunnel[J].Engineering Journal of Wuhan University,2012,44(3):321-325.
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[13]CHEN X H,PAO W,LI X.Coupled thermo-hydromechanical model with consideration of thermal-osmosis based on modified mixture theory[J].International Journal of Engineering Science,2013,64(1):1-13.
[14]CHO W J,LEE J O,KWON S.Analysis of thermos-hydro-mechanical process in the engineered barrier system of a high-level waste repository[J].Nuclear Engineering and Design,2010,240(6):1688-1698.
[15]KELKAR S,LEWIS K,KARRA S,et al.A simulator for modeling coupled thermo-hydro-mechanical processes in subsurface geological media[J].International Journal of Rock Mechanics and Mining Sciences,2014,70(70):569-580.
[16]赵阳升,王瑞凤,胡耀青.高温岩体地热开发的块裂介质固流热耦合三维数值模拟[J].岩石力学与工程学报,2002,21(12):1751-1755.ZHAO Yang-sheng,WANG Rui-feng,HU Yao-qing,et al.3D numerical simulation for coupled THM of rock matrix-fractured media in heat extraction in HDR[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(12):1751-1755.
[17]黄涛.裂隙岩体渗流-应力-温度耦合作用研究[J].岩石力学与工程学报,2002,21(1):77-82.HUANG Tao.Coupling study among seepage-stresstemperature in fractured rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(1):77-82.
[18]周英博,张玉军.压力溶解对颗粒聚集岩体中热-水-应力耦合作用的弹塑性有限元分析[J].岩土力学,2016,37(6):1781-1790.ZHOU Ying-bo,ZHANG Yu-jun.Elastoplastic finite element analysis for influences of pressure solution on thermo-hydro-mechanical coupling in aggregate rock[J].Rock and Soil Mechanics,2016,37(6):1781-1790.
[19]朱万成,魏晨慧,田军,等.岩石损伤过程中的热-流-力耦合模型及其应用初探[J].岩土力学,2009,30(12):3852-3857.ZHU Wan-cheng,WEI Chen-hui,TIAN Jun,et al.Coupled thermal-hydraulic-mechanical model during rock damage and its preliminary application[J].Rock and Soil Mechanics,2009,30(12):3852-3857.
[20]李连崇,唐春安,杨天鸿,等.岩石破裂过程THMD耦合数值模型研究[J].计算力学学报,2008,25(6):764-769.LI Lian-chong,TANG Chun-an,YANG Tian-hong,et al.Investigation on coupled thermo-hydro-mechanicaldamage(THMD)model for rock failure process[J].Chinese Journal of Computational Mechanics,2008,25(6):764-769.
[21]谭贤君,陈卫忠,伍国军,等.低温冻融条件下岩体温度-渗流-应力-损伤(THMD)耦合模型研究及其在寒区隧道中的应用[J].岩石力学与工程学报,2013,32(2):239-250.TAN Xian-jun,CHEN Wei-zhong,WU Guo-jun,et al.Study of the thermo-hydro-mechanical-damage(THMD)coupled model in the condition of freeze-thaw cycles and its application to cold region tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(2):239
[22]江权,冯夏庭,陈国庆.考虑高地应力下围岩劣化的硬岩本构模型研究[J].岩石力学与工程学报,2008,27(1):144-152.JIANG Quan,FENG Xia-ting,CHEN Guo-qing.Study of constitutive model of hard rock considering surrounding rock deterioration under high geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(1):144-152.
[23]邓华锋,胡安龙,李建林,等.水岩作用下砂岩劣化损伤统计本构模型[J].岩土力学,2017,38(3):631-639.DENG Hua-feng,HU An-long,LI Jian-lin,et al.Statistical damage constitutive model of sandstone under water-rock interaction[J].Rock and Soil Mechanics,2017,38(3):631-639.
[24]朱合华,闫治国,邓涛,等.3种岩石高温后力学性质的试验研究[J].岩石力学与工程学报,2006,25(10):1945-1950.ZHU He-hua,YAN Zhi-guo,DENG Tao,et al.Testing study on mechanical properties of tuff,granite and breccias after high temperatures[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(10):1945
[25]Itasca Consulting Group,Inc.FLAC3D.Fast Lagrangian analysis of continua in 3 dimensions(Version 3.0)user’s manual[M].Minneapolis:Itasca Consulting Group,Inc.,2005.
[2]王文革.乌东德水电站地热异常研究[J].西北水电,2006,(4):18-22.WANG Wen-ge.Study on geothermal anomaly of Wudongde hydropower project[J].Northwest Hydropower,2006,(4):18-22.
[3]谢仕群.帕米尔高原高地温地质条件下的洞室开挖施工技术[J].西北水电,2010,(5):42-44.XIE Shi-qun.Technology of tunneling under the geological conditions of high ground temperature on the Pamirs Plateau[J].Northwest Hydropower,2010,(5):42-44.
[4]刘乃飞,李宁,余春海,等.布仑口水电站高温引水发电隧洞受力特性研究[J].水利水运工程学报,2014,(4):14-21.LIU Nai-fei,LI Ning,YU Chun-hai,et al.Analysis of mechanical characteristics for high-temperature diversion tunnel of Bulunkou Hydropower Station[J].Hydro-Science and Engineering,2014,(4):14-21.
[5]林睦曾.岩石热物理学及其工程应用[M].重庆:重庆大学出版社,1991.LIN Mu-zeng.Thermal physics of rock and its application[M].Chongqing:Chongqing University Press,1991.
[6]张有天.水工隧洞建设的经验和教训(上)[J].贵州水力发电,2001,15(4):76-84.ZHANG You-tian.Experiences and lessons of the hydraulic tunnel construction(First)[J].Guizhou Water Power,2001,15(4):76-84.
[7]陈卫忠,伍国军,戴永浩,等.锦屏二级水电站深埋引水隧洞稳定性研究[J].岩土力学,2008,30(8):1185-1190.CHEN Wei-zhong,WU Guo-jun,DAI Yong-hao,et al.Stability analysis of diversion tunnel for Jinping Hydropower Station[J].Rock and Soil Mechanics,2008,30(8):1184-1190.
[8]伍鹤皋,尚斌,苏凯.高压隧洞透水衬砌结构研究[J].武汉大学学报(工学版),2012,44(3):321-325.WU He-gao,SHANG Bin,SU Kai.Research of permeable lining structure for high pressure tunnel[J].Engineering Journal of Wuhan University,2012,44(3):321-325.
[9]苏凯,伍鹤皋,周创兵.内水压力下水工隧洞衬砌与围岩承载特性研究[J].岩土力学,2010,31(8):2408-2411.SU Kai,WU He-gao,ZHOU Chuang-bing.Study of combined bearing characteristics of lining and surrounding rock for hydraulic tunnel under internal water pressure[J].Rock and Soil Mechanics,2010,31(8):2408-2411.
[10]侯靖,胡敏云.水工高压隧洞结构设计中若干问题的讨论[J].水利学报,2001,32(7):36-40.HOU Jing,HU Min-yun.Discussion on some problems in design of high pressure tunnel for hydro projects[J].Journal of Hydraulic Engineering,2001,32(7):36-40.
[11]肖明.地下高压钢筋混凝土岔管渗水开裂三维数值分析计算[J].岩石力学与工程学报,2002,21(7):1022-1026.XIAO Ming.Three-dimensional numerical analysis of lining seepage crack of underground concrete bifurcated pipe with high pressure water[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(7):1022-1026.
[12]杜小凯,任青文,夏宁.高压引水隧洞若干问题的研究现状和存在的问题[J].水力发电,2007,33(6):65-68.DU Xiao-kai,REN Qing-wen,XIA Ning.Status quo of the study on the several problems of high pressure diversion tunnel and its existing problems[J].Water Power,2007,33(6):65-68.
[13]CHEN X H,PAO W,LI X.Coupled thermo-hydromechanical model with consideration of thermal-osmosis based on modified mixture theory[J].International Journal of Engineering Science,2013,64(1):1-13.
[14]CHO W J,LEE J O,KWON S.Analysis of thermos-hydro-mechanical process in the engineered barrier system of a high-level waste repository[J].Nuclear Engineering and Design,2010,240(6):1688-1698.
[15]KELKAR S,LEWIS K,KARRA S,et al.A simulator for modeling coupled thermo-hydro-mechanical processes in subsurface geological media[J].International Journal of Rock Mechanics and Mining Sciences,2014,70(70):569-580.
[16]赵阳升,王瑞凤,胡耀青.高温岩体地热开发的块裂介质固流热耦合三维数值模拟[J].岩石力学与工程学报,2002,21(12):1751-1755.ZHAO Yang-sheng,WANG Rui-feng,HU Yao-qing,et al.3D numerical simulation for coupled THM of rock matrix-fractured media in heat extraction in HDR[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(12):1751-1755.
[17]黄涛.裂隙岩体渗流-应力-温度耦合作用研究[J].岩石力学与工程学报,2002,21(1):77-82.HUANG Tao.Coupling study among seepage-stresstemperature in fractured rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2002,21(1):77-82.
[18]周英博,张玉军.压力溶解对颗粒聚集岩体中热-水-应力耦合作用的弹塑性有限元分析[J].岩土力学,2016,37(6):1781-1790.ZHOU Ying-bo,ZHANG Yu-jun.Elastoplastic finite element analysis for influences of pressure solution on thermo-hydro-mechanical coupling in aggregate rock[J].Rock and Soil Mechanics,2016,37(6):1781-1790.
[19]朱万成,魏晨慧,田军,等.岩石损伤过程中的热-流-力耦合模型及其应用初探[J].岩土力学,2009,30(12):3852-3857.ZHU Wan-cheng,WEI Chen-hui,TIAN Jun,et al.Coupled thermal-hydraulic-mechanical model during rock damage and its preliminary application[J].Rock and Soil Mechanics,2009,30(12):3852-3857.
[20]李连崇,唐春安,杨天鸿,等.岩石破裂过程THMD耦合数值模型研究[J].计算力学学报,2008,25(6):764-769.LI Lian-chong,TANG Chun-an,YANG Tian-hong,et al.Investigation on coupled thermo-hydro-mechanicaldamage(THMD)model for rock failure process[J].Chinese Journal of Computational Mechanics,2008,25(6):764-769.
[21]谭贤君,陈卫忠,伍国军,等.低温冻融条件下岩体温度-渗流-应力-损伤(THMD)耦合模型研究及其在寒区隧道中的应用[J].岩石力学与工程学报,2013,32(2):239-250.TAN Xian-jun,CHEN Wei-zhong,WU Guo-jun,et al.Study of the thermo-hydro-mechanical-damage(THMD)coupled model in the condition of freeze-thaw cycles and its application to cold region tunnels[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(2):239
[22]江权,冯夏庭,陈国庆.考虑高地应力下围岩劣化的硬岩本构模型研究[J].岩石力学与工程学报,2008,27(1):144-152.JIANG Quan,FENG Xia-ting,CHEN Guo-qing.Study of constitutive model of hard rock considering surrounding rock deterioration under high geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(1):144-152.
[23]邓华锋,胡安龙,李建林,等.水岩作用下砂岩劣化损伤统计本构模型[J].岩土力学,2017,38(3):631-639.DENG Hua-feng,HU An-long,LI Jian-lin,et al.Statistical damage constitutive model of sandstone under water-rock interaction[J].Rock and Soil Mechanics,2017,38(3):631-639.
[24]朱合华,闫治国,邓涛,等.3种岩石高温后力学性质的试验研究[J].岩石力学与工程学报,2006,25(10):1945-1950.ZHU He-hua,YAN Zhi-guo,DENG Tao,et al.Testing study on mechanical properties of tuff,granite and breccias after high temperatures[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(10):1945
[25]Itasca Consulting Group,Inc.FLAC3D.Fast Lagrangian analysis of continua in 3 dimensions(Version 3.0)user’s manual[M].Minneapolis:Itasca Consulting Group,Inc.,2005.