高地温水工高压隧洞结构模型试验研究
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摘要
为揭示高地温梯度与高内水压力联合作用下水工隧洞围岩的承载特性,在研制完整硬岩多物理场相似材料的基础上,通过温度荷载与内水压力联合加载技术开发,结合声发射的信号监测与空间定位技术,开展大比尺高地温水工高压隧洞的水工结构模型试验,对隧洞围岩的温度场、渗压场、声发射和裂纹发育的动态演化过程进行了测试与分析。试验结果表明,与非高地温条件相比,高地温条件下水工高压隧洞围岩出现水力劈裂所需的临界内水压力明显较低;与非高地温条件下围岩出现少数几条主裂缝不同,高地温条件下围岩主裂缝之间的次生裂缝甚为发育;高地温条件下水工高压隧洞围岩的热-水-力多物理场耦合效应明显,内水压力不变条件下围岩的裂缝扩展与损伤增长呈现非连续阶跃变化特征;高地应力条件下高地温水工高压隧洞水力劈裂位置与裂缝扩展受地应力侧限系数影响较大。
To reveal the bearing characteristics of surrounding rock mass of hydraulic tunnels under the combined effects of high geotemperature and high internal water pressure, this study conducts experimental tests on a large-scale structural model of a hydraulic pressure tunnel with large geotemperature gradients in multi-physical fields through developing a similar material of complete hard rock mass. For the tests, we adopt acoustic emission techniques for signal monitoring and locating,develop a new loading technique of combined temperature loads and internal water pressure, and analyze the dynamic evolution processes of temperature field, pore pressure field, acoustic emission, and fracture propagation. Results show that compared to the condition without high geotemperature, the critical internal water pressure of the surrounding rock mass of the tunnel at the start of hydraulic fracturing is lowered obviously. In a high geotemperature environment, the induced cracks between the main fractures in the rock mass have evolved quite completely, manifesting the difference from the normal geotemperature cases where only a few main fractures are mobilized. And the rock mass has undergone an obvious coupling effect of thermo-hydro-mechanical fields, and the fracture propagation and increasing damage of the rock mass are featured with discontinued step evolution under constant water pressure. Under high in-situ stress conditions, the locations of hydraulic fractures and fracture propagation are influenced significantly by the lateral confining coefficient of in-situ stress.
To reveal the bearing characteristics of surrounding rock mass of hydraulic tunnels under the combined effects of high geotemperature and high internal water pressure, this study conducts experimental tests on a large-scale structural model of a hydraulic pressure tunnel with large geotemperature gradients in multi-physical fields through developing a similar material of complete hard rock mass. For the tests, we adopt acoustic emission techniques for signal monitoring and locating,develop a new loading technique of combined temperature loads and internal water pressure, and analyze the dynamic evolution processes of temperature field, pore pressure field, acoustic emission, and fracture propagation. Results show that compared to the condition without high geotemperature, the critical internal water pressure of the surrounding rock mass of the tunnel at the start of hydraulic fracturing is lowered obviously. In a high geotemperature environment, the induced cracks between the main fractures in the rock mass have evolved quite completely, manifesting the difference from the normal geotemperature cases where only a few main fractures are mobilized. And the rock mass has undergone an obvious coupling effect of thermo-hydro-mechanical fields, and the fracture propagation and increasing damage of the rock mass are featured with discontinued step evolution under constant water pressure. Under high in-situ stress conditions, the locations of hydraulic fractures and fracture propagation are influenced significantly by the lateral confining coefficient of in-situ stress.
引文
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[3]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 Naifei,LI Ning,YU Chunhai,et al.Analysis of mechanical characteristics for high temperature diversion tunnel of Bulunkou Hydropower Station[J].HydroScience and Engineering,2014(4):14-21.(in Chinese)
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[5]张岩,李宁,张浩博,等.温差影响下水工隧洞喷层结构的早期劈拉强度试验研究[J].水力发电学报,2014,33(2):221-229.ZHANG Yan,LI Ning,ZHANG Haobo,et al.Experimental study on early splitting strength of hydraulic tunnel shotcret layer under temperature differences[J].Journal of Hydroelectric Engineering,2014,33(2):221-229.(in Chinese)
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[9]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,2001,21(7):36-40.HOU Jing,HU Minyun.Discussion on some problems in design of high pressure tunnel for hydro projects[J].Journal of Hydraulic Engineering,2001,21(7):36-40.(in Chinese)
[10]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):2407-2412.SU Kai,WU Hegao,ZHOU Chuangbing.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):2407-2412.(in Chinese)
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[12]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 Youtian.Experiences and lessons of the hydraulic tunnel construction(First)[J].Guizhou Water Power,2001,15(4):76-84.(in Chinese)
[13]SCHLEISS A.Design of reinforced concrete linings of pressure tunnels and shafts[J].Hydropower&Dams,1997(3):88-94.
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[15]何英杰,张述琴,吕国梁.穿黄隧道内外衬联合受力结构模型试验研究[J].长江科学院院报,2002,19(S1):64-67.HE Yingjie,ZHANG Shuqin,LU Guoliang.Experiment research on united action of inside and outside liner of Yellow River-crossing tunnel of Water Transfer Project from South to North[J].Journal of Yangtze River Scientific Research Institute,2002,19(S1):64-67.(in Chinese)
[16]王克忠,李仲奎.深埋长大引水隧洞三维物理模型渗透性试验研究[J].岩石力学与工程学报,2009,28(4):725-731.WANG Kezhong,LI Zhongkui.Study on 3D physical model test of seepage of deep-buried long and large diversion tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(4):725-731.(in Chinese)
[17]沈威.圆形水工压力隧洞衬砌变形特性与限裂设计研究[D].大连:大连理工大学,2012.SHEN Wei.Investigation on the deformation feature and crack restricting design of circular lining of hydraulic pressure tunnel[D].Dalian:Dalian University of Technology,2012.(in Chinese)
[18]FUMAGALLI E.Statical and geomechanical models[M].Springer,1973.
[19]陈兴华.脆性材料结构模型试验[M].北京:水利电力出版社,1984.CHEN Xinghua.Structure model test for brittle material[M].Beijing:Water Resources and Electric Power Press,1984.(in Chinese)
[20]FEI W,ZHANG L,ZHANG R.Experimental study on a geo-mechanical model of a high arch dam[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(2):299-306.
[21]工程岩体分级标准:GB 50218-2014[S].北京:中国计划出版社,2014.Standard for engineering classification of rock masses:GB 50218-2014[S].Beijing:China Planning Press,2014.(in Chinese)
[22]GROSSE C U,OHTSU M.Acoustic emission testing[M].Springer,2008.
[23]CHEN L H,CHEN W C,CHEN Y-C,et al.Investigation of hydraulic fracture propagation using a post-peak control system coupled with acoustic emission[J].Rock Mechanics and Rock Engineering,2015,48(3):1233-1248.
[24]ZHU W C,TANG C A.Micromechanical model for simulating the fracture process of rock[J].Rock Mechanics&Rock Engineering,2004,37(1):25-56.
[2]周菊兰,郑道明.地下工程施工中高地温、高温热水治理技术研究[J].四川水力发电,2011,30(5):81-84.ZHOU Julan,ZHENG Daoming.Treatment technology research on high geotemperature and high temperature hot water in underground engineering constructions[J].Sichuan Water Power,2011,30(5):81-84.(in Chinese)
[3]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 Naifei,LI Ning,YU Chunhai,et al.Analysis of mechanical characteristics for high temperature diversion tunnel of Bulunkou Hydropower Station[J].HydroScience and Engineering,2014(4):14-21.(in Chinese)
[4]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 Muzeng.Rock thermophysics and its application in engineering[M].Chongqing:Chongqing University Press,1991.(in Chinese)
[5]张岩,李宁,张浩博,等.温差影响下水工隧洞喷层结构的早期劈拉强度试验研究[J].水力发电学报,2014,33(2):221-229.ZHANG Yan,LI Ning,ZHANG Haobo,et al.Experimental study on early splitting strength of hydraulic tunnel shotcret layer under temperature differences[J].Journal of Hydroelectric Engineering,2014,33(2):221-229.(in Chinese)
[6]刘春龙,张永生,袁继国,等.高温引水隧洞应力场分布的研究[J].水利与建筑工程学报,2015,13(4):66-71.LIU Chunlong,ZHANG Yongsheng,YUAN Jiguo,et al.Study on the distribution of stress field in hightemperature diversion tunnels[J].Journal of Water Resources and Architectural Engineering,2015,13(4):66-71.(in Chinese)
[7]FERNáNDEZ G.Behavior of pressure tunnels and guidelines for liner design[J].Journal of Geotechnical Engineering,1994,120(10):1768-1791.
[8]江权,冯夏庭,周辉.锦屏二级水电站深埋引水隧洞群允许最小间距研究[J].岩土力学,2008,29(3):656-662.JIANG Quan,FENG Xiating,ZHOU Hui.Study on acceptable minimum interval of long deeply burial hydropower tunnels in Jinping II Hydropower Station[J].Rock and Soil Mechanics,2008,29(3):656-662.(in Chinese)
[9]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,2001,21(7):36-40.HOU Jing,HU Minyun.Discussion on some problems in design of high pressure tunnel for hydro projects[J].Journal of Hydraulic Engineering,2001,21(7):36-40.(in Chinese)
[10]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):2407-2412.SU Kai,WU Hegao,ZHOU Chuangbing.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):2407-2412.(in Chinese)
[11]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),2011,44(3):321-325.WU Hegao,SHANG Bin,SU Kai.Research of permeable lining structure for high pressure tunnel[J].Engineering Journal of Wuhan University,2011,44(3):321-325.(in Chinese)
[12]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 Youtian.Experiences and lessons of the hydraulic tunnel construction(First)[J].Guizhou Water Power,2001,15(4):76-84.(in Chinese)
[13]SCHLEISS A.Design of reinforced concrete linings of pressure tunnels and shafts[J].Hydropower&Dams,1997(3):88-94.
[14]刘幸,王天稳.柘溪水电站引水隧洞钢筋混凝土衬砌仿真模型试验研究[J].水电站设计,1997,13(4):61-65.LIU Xing,WANG Tianwen.Simulated model test of reinforced concreted lining of diversion tunnel of Zhexi Hydropower Station[J].Design of Hydroelectric Power Station,1997,13(4):61-65.(in Chinese)
[15]何英杰,张述琴,吕国梁.穿黄隧道内外衬联合受力结构模型试验研究[J].长江科学院院报,2002,19(S1):64-67.HE Yingjie,ZHANG Shuqin,LU Guoliang.Experiment research on united action of inside and outside liner of Yellow River-crossing tunnel of Water Transfer Project from South to North[J].Journal of Yangtze River Scientific Research Institute,2002,19(S1):64-67.(in Chinese)
[16]王克忠,李仲奎.深埋长大引水隧洞三维物理模型渗透性试验研究[J].岩石力学与工程学报,2009,28(4):725-731.WANG Kezhong,LI Zhongkui.Study on 3D physical model test of seepage of deep-buried long and large diversion tunnel[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(4):725-731.(in Chinese)
[17]沈威.圆形水工压力隧洞衬砌变形特性与限裂设计研究[D].大连:大连理工大学,2012.SHEN Wei.Investigation on the deformation feature and crack restricting design of circular lining of hydraulic pressure tunnel[D].Dalian:Dalian University of Technology,2012.(in Chinese)
[18]FUMAGALLI E.Statical and geomechanical models[M].Springer,1973.
[19]陈兴华.脆性材料结构模型试验[M].北京:水利电力出版社,1984.CHEN Xinghua.Structure model test for brittle material[M].Beijing:Water Resources and Electric Power Press,1984.(in Chinese)
[20]FEI W,ZHANG L,ZHANG R.Experimental study on a geo-mechanical model of a high arch dam[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(2):299-306.
[21]工程岩体分级标准:GB 50218-2014[S].北京:中国计划出版社,2014.Standard for engineering classification of rock masses:GB 50218-2014[S].Beijing:China Planning Press,2014.(in Chinese)
[22]GROSSE C U,OHTSU M.Acoustic emission testing[M].Springer,2008.
[23]CHEN L H,CHEN W C,CHEN Y-C,et al.Investigation of hydraulic fracture propagation using a post-peak control system coupled with acoustic emission[J].Rock Mechanics and Rock Engineering,2015,48(3):1233-1248.
[24]ZHU W C,TANG C A.Micromechanical model for simulating the fracture process of rock[J].Rock Mechanics&Rock Engineering,2004,37(1):25-56.