高地应力区大型洞室锚索时效受力特征及长期承载风险分析
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摘要
深层预应力锚索支护是大型地下洞室围岩稳定控制的主要工程措施。针对高应力区岩体开挖卸荷稳定与锚固支护系统长期承载安全问题,通过对系统锚索安全长期监测成果的深入分析,研究锦屏一级水电站地下厂房系统锚索开挖期和开挖完成后5 a时间的受力特征、时空变化规律,分析锚索预应力随时间演化的时效特征,探讨锚索结构受力影响因素和高应力下长期承载风险,同时辅以数值模拟等手段对锚固系统长期安全性进行综合评价。研究结果表明,与常规洞室表现不同,该地下洞室大部分深层锚索超过设计锁定值,锚索系统负载高,持续增长时间长,时效性十分显著,开挖全部完成后2 a内才逐步趋于收敛,2～5 a基本稳定;锚索长期承载能力影响因素主要有岩体蠕变、锚索初始张拉应力、锚索施工与应力不均匀等;锚索系统长期承载安全是有保障的。
Prestressed anchor cable is the main engineering measure for stability control of surrounding rock mass in large underground caverns. Aiming at the problem of unloading stability of rock mass excavation and long-term bearing safety of anchor support system in high-stress area, the long-term in-situ monitoring results of systematic anchor cable are deeply analysed. In this paper, we investigate the stress characteristics and space-time variation of the anchor cable, and the time-dependent characteristics of the pre-stress of anchor cable in the underground powerhouse system of Jinping I hydropower station located in Southwest of China. The factors influencing the long-term safety of high bearing anchorage cable structure are discussed, and the long-term safety of anchoring system is evaluated with the numerical simulation method. The obtained results show obviously different from them in the conventional cavern. Most of the anchor cables for supporting deep rock mass of this underground cavern exceed the designed locking value, the load of the cable system is high, the continuous growth time becomes long, and the time effect characteristics is greatly significant. The main factors affecting the long-term bearing capacity of anchor cable include the creep of rock mass, initial tension stress of anchor cable, uneven stress of anchor cable. The analysis indicates that the anchorage cable long-term bearing safety is guaranteed.
Prestressed anchor cable is the main engineering measure for stability control of surrounding rock mass in large underground caverns. Aiming at the problem of unloading stability of rock mass excavation and long-term bearing safety of anchor support system in high-stress area, the long-term in-situ monitoring results of systematic anchor cable are deeply analysed. In this paper, we investigate the stress characteristics and space-time variation of the anchor cable, and the time-dependent characteristics of the pre-stress of anchor cable in the underground powerhouse system of Jinping I hydropower station located in Southwest of China. The factors influencing the long-term safety of high bearing anchorage cable structure are discussed, and the long-term safety of anchoring system is evaluated with the numerical simulation method. The obtained results show obviously different from them in the conventional cavern. Most of the anchor cables for supporting deep rock mass of this underground cavern exceed the designed locking value, the load of the cable system is high, the continuous growth time becomes long, and the time effect characteristics is greatly significant. The main factors affecting the long-term bearing capacity of anchor cable include the creep of rock mass, initial tension stress of anchor cable, uneven stress of anchor cable. The analysis indicates that the anchorage cable long-term bearing safety is guaranteed.
引文
[1]王泰恒,许文年,陈池,等.预应力锚固技术基本理论与实践[M].北京:中国水利水电出版社,2007.WANG Tai-heng,XU Wen-nian,CHEN Chi,et al.Basic theory and practice of prestressed anchorage technology[M].Beijing:China Water Conservancy and Hydropower Press,2007.
[2]程良奎,韩军,张培文.岩土锚固工程的长期性能与安全评价[J].岩石力学与工程学报,2008,27(5):865-872.CHENG Liang-kui,HAN Jun,ZHANG Pei-wen.Longterm performance and safety evaluation of geotechnical anchorage engineering[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(5):865-872.
[3]张乐文,李术才.岩土锚固的现状与发展[J].岩石力学与工程学报,2003,22(增刊1):2214-2221.ZHANG Le-wen,LI Shu-cai.Status quo and development of rock soil anchoring[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(Supp.1):2214-2221.
[4]CARRANZA-TORRES C.Analytical and numerical study of the mechanics of rock bolt reinforcement around tunnels in rock masses[J].Rock Mechanics Rock Engineering,2009(42):175-228.
[5]LI DANQI,HOSSEIN MASOUMI,SERKAN SAYDAM.A constitutive model for load-displacement performance of modified cable bolts[J].Tunnelling and Underground Space Technology,2017,(68):95-105.
[6]LI Shu-cai,WANG Hong-tao,WANG Qi.Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress[J].Journal of Central South University,2016,(23):440-448.
[7]邓建,肖明,谢冰冰.预应力锚索受力特性与初始张拉吨位优化分析[J].岩土力学,2016,37(8):2359-2365.DENG Jian,XIAO Ming,XIE Bing-bing.Analysis of stress characteristics and initial tension optimization of prestressed anchor cable[J].Rock and Soil Mechanics,2016,37(8):2359-2365.
[8]李正刚.二滩水电站地下厂房系统洞室围岩变形研究[J].四川水力发电,2004,23(1):43-47.LI Zheng-gang.Deformation of surrounding rock in Eetan’s underground powerhouse unit[J].Sichuan Water Power,2004,23(1):43-47.
[9]党林才,侯靖,吴世勇.中国水电地下工程建设与关键技术[M].北京:中国水利水电出版社,2012.DANG Lin-cai,HOU Jing,WU Shi-yong.Chinese hydropower underground engineering construction and key technologies[M].Beijing:China Water and Hydropower Press,2012.
[10]江权,陈建林,冯夏庭.大型地下洞室对穿预应力锚索失效形式与耦合模型[J].岩土力学,2013,34(8):2271-2279.JIANG Quan,CHEN Jian-lin,FENG Xia-ting.The failure form and coupling model of prestressed anchorage cable for large underground caverns and coupling model[J].Rock and Soil Mechanics,2013,34(8):2271-2279.
[11]刘泉声,雷广峰,彭星新.深部裂隙岩体锚固机制研究进展与思考[J].岩石力学与工程学报,2016,35(2):312-332.LIU Quan-sheng,LEI Guang-feng,PENG Xing-xin.Research progress and thinking on anchorage mechanism of deep fractured rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(2):312-332.
[12]周钟,廖成刚,汤雪峰,等.雅砻江锦屏一级水电站地下厂房洞室群施工期围岩稳定与支护复核设计报告[R].成都:中国水电顾问集团成都勘测设计研究院,2009.ZHOU Zhong,LIAO Cheng-gang,TANG Xue-feng,et al.The Yalong river hydropower station of JinpingⅠunderground caverns during construction of surrounding rock stability and support design review report[R].Chengdu:China Hydropower Consulting Group Chengdu Survey and Design Institute,2009.
[13]李仲奎,周钟,汤雪峰.锦屏一级水电站地下厂房洞室群稳定性分析与思考[J].岩石力学与工程学报,2009,28(11):2167-2175.LI Zhong-kui,ZHOU Zhong,TANG Xue-feng.Analysis and reflection on stability of underground powerhouse caverns in Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(11):2167-2175.
[14]黄润秋,黄达,段绍辉.锦屏Ⅰ级水电站地下厂房施工期围岩变形开裂特征及地质力学机制研究[J].岩石力学与工程学报,2011,30(1):23-35.HUANG Run-qiu,HUANG Da,DUAN Shao-hui.Deformation and cracking characteristics and geomechanical mechanism of surrounding rock during construction period of underground powerhouse of Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(1):23-35.
[15]魏进兵,邓建辉,王悌剀,等.锦屏一级水电站地下厂房围岩变形与破坏特征分析[J].岩石力学与工程学报,2010,29(6):1198-1205.WEI Jin-bing,DENG Jian-hui,WANG Ti-kai,et al.Analysis of the deformation and failure characteristics of surrounding rock of underground powerhouse of Jinping Ihydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(6):1198-1205.
[16]黄书岭,王继敏,丁秀丽,等.基于层状岩体卸荷演化的锦屏Ⅰ级地下厂房洞室群稳定性与调控[J].岩石力学与工程学报,2011,30(11):2203-2216.HUANG Shu-ling,WANG Ji-min,DING Xiu-li,et al.Based on the unloading evolution of layered rock mass,the stability and regulation of the first class underground powerhouse caverns in Jinping[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(11):2203-2216.
[17]朱维申,齐银萍,郭运华.锦屏I级水电站地下厂房围岩变形破裂的三维损伤流变分析[J].岩石力学与工程学报,2012,31(5):865-872.ZHU Wei-shen,QI Yin-ping,GUO Yun-hua.Three dimensional damage and rheological analysis of surrounding rock deformation and failure of underground powerhouse of Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(5):865-872.
[18]侯东奇,冯梅,廖成刚,等.大型地下洞室锚索系统支护工程实践[J].岩石力学与工程学报,2012,31(5):963-972.HOU Dong-qi,FENG Mei,LIAO Cheng-gang,et al.Support engineering practice of large underground cavern anchorage system[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(5):963-972.
[19]中国国家经济贸易委员会.DL/T 5176-2003水电工程预应力锚固设计规范[S].北京:中国计划出版社,2003.State Economic and Trade Commission of the People’s Republic of China.DL/T 5176-2003 Code for prestressed anchorage design of hydropower projects[S].Beijing:China Planning Publishing House,2003.
[20]中华人民共和国水利部.SL212-2012水工预应力锚固设计规范[S].北京:中国水利水电出版社,2012.Ministry of Water Resources of the People’s Republic of China.Design code for prestressed anchorage of hydraulic engineering SL212-2012[S].Beijing:China Water Resources and Hydropower Publishing House,2012.
[21]The British Standard Institution.BS EN 1537:2013Execution of special geotechnical works-Ground anchors[S].[S.l.]:BSI Standard Publication,2013.
[2]程良奎,韩军,张培文.岩土锚固工程的长期性能与安全评价[J].岩石力学与工程学报,2008,27(5):865-872.CHENG Liang-kui,HAN Jun,ZHANG Pei-wen.Longterm performance and safety evaluation of geotechnical anchorage engineering[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(5):865-872.
[3]张乐文,李术才.岩土锚固的现状与发展[J].岩石力学与工程学报,2003,22(增刊1):2214-2221.ZHANG Le-wen,LI Shu-cai.Status quo and development of rock soil anchoring[J].Chinese Journal of Rock Mechanics and Engineering,2003,22(Supp.1):2214-2221.
[4]CARRANZA-TORRES C.Analytical and numerical study of the mechanics of rock bolt reinforcement around tunnels in rock masses[J].Rock Mechanics Rock Engineering,2009(42):175-228.
[5]LI DANQI,HOSSEIN MASOUMI,SERKAN SAYDAM.A constitutive model for load-displacement performance of modified cable bolts[J].Tunnelling and Underground Space Technology,2017,(68):95-105.
[6]LI Shu-cai,WANG Hong-tao,WANG Qi.Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress[J].Journal of Central South University,2016,(23):440-448.
[7]邓建,肖明,谢冰冰.预应力锚索受力特性与初始张拉吨位优化分析[J].岩土力学,2016,37(8):2359-2365.DENG Jian,XIAO Ming,XIE Bing-bing.Analysis of stress characteristics and initial tension optimization of prestressed anchor cable[J].Rock and Soil Mechanics,2016,37(8):2359-2365.
[8]李正刚.二滩水电站地下厂房系统洞室围岩变形研究[J].四川水力发电,2004,23(1):43-47.LI Zheng-gang.Deformation of surrounding rock in Eetan’s underground powerhouse unit[J].Sichuan Water Power,2004,23(1):43-47.
[9]党林才,侯靖,吴世勇.中国水电地下工程建设与关键技术[M].北京:中国水利水电出版社,2012.DANG Lin-cai,HOU Jing,WU Shi-yong.Chinese hydropower underground engineering construction and key technologies[M].Beijing:China Water and Hydropower Press,2012.
[10]江权,陈建林,冯夏庭.大型地下洞室对穿预应力锚索失效形式与耦合模型[J].岩土力学,2013,34(8):2271-2279.JIANG Quan,CHEN Jian-lin,FENG Xia-ting.The failure form and coupling model of prestressed anchorage cable for large underground caverns and coupling model[J].Rock and Soil Mechanics,2013,34(8):2271-2279.
[11]刘泉声,雷广峰,彭星新.深部裂隙岩体锚固机制研究进展与思考[J].岩石力学与工程学报,2016,35(2):312-332.LIU Quan-sheng,LEI Guang-feng,PENG Xing-xin.Research progress and thinking on anchorage mechanism of deep fractured rock mass[J].Chinese Journal of Rock Mechanics and Engineering,2016,35(2):312-332.
[12]周钟,廖成刚,汤雪峰,等.雅砻江锦屏一级水电站地下厂房洞室群施工期围岩稳定与支护复核设计报告[R].成都:中国水电顾问集团成都勘测设计研究院,2009.ZHOU Zhong,LIAO Cheng-gang,TANG Xue-feng,et al.The Yalong river hydropower station of JinpingⅠunderground caverns during construction of surrounding rock stability and support design review report[R].Chengdu:China Hydropower Consulting Group Chengdu Survey and Design Institute,2009.
[13]李仲奎,周钟,汤雪峰.锦屏一级水电站地下厂房洞室群稳定性分析与思考[J].岩石力学与工程学报,2009,28(11):2167-2175.LI Zhong-kui,ZHOU Zhong,TANG Xue-feng.Analysis and reflection on stability of underground powerhouse caverns in Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(11):2167-2175.
[14]黄润秋,黄达,段绍辉.锦屏Ⅰ级水电站地下厂房施工期围岩变形开裂特征及地质力学机制研究[J].岩石力学与工程学报,2011,30(1):23-35.HUANG Run-qiu,HUANG Da,DUAN Shao-hui.Deformation and cracking characteristics and geomechanical mechanism of surrounding rock during construction period of underground powerhouse of Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(1):23-35.
[15]魏进兵,邓建辉,王悌剀,等.锦屏一级水电站地下厂房围岩变形与破坏特征分析[J].岩石力学与工程学报,2010,29(6):1198-1205.WEI Jin-bing,DENG Jian-hui,WANG Ti-kai,et al.Analysis of the deformation and failure characteristics of surrounding rock of underground powerhouse of Jinping Ihydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(6):1198-1205.
[16]黄书岭,王继敏,丁秀丽,等.基于层状岩体卸荷演化的锦屏Ⅰ级地下厂房洞室群稳定性与调控[J].岩石力学与工程学报,2011,30(11):2203-2216.HUANG Shu-ling,WANG Ji-min,DING Xiu-li,et al.Based on the unloading evolution of layered rock mass,the stability and regulation of the first class underground powerhouse caverns in Jinping[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(11):2203-2216.
[17]朱维申,齐银萍,郭运华.锦屏I级水电站地下厂房围岩变形破裂的三维损伤流变分析[J].岩石力学与工程学报,2012,31(5):865-872.ZHU Wei-shen,QI Yin-ping,GUO Yun-hua.Three dimensional damage and rheological analysis of surrounding rock deformation and failure of underground powerhouse of Jinping I hydropower station[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(5):865-872.
[18]侯东奇,冯梅,廖成刚,等.大型地下洞室锚索系统支护工程实践[J].岩石力学与工程学报,2012,31(5):963-972.HOU Dong-qi,FENG Mei,LIAO Cheng-gang,et al.Support engineering practice of large underground cavern anchorage system[J].Chinese Journal of Rock Mechanics and Engineering,2012,31(5):963-972.
[19]中国国家经济贸易委员会.DL/T 5176-2003水电工程预应力锚固设计规范[S].北京:中国计划出版社,2003.State Economic and Trade Commission of the People’s Republic of China.DL/T 5176-2003 Code for prestressed anchorage design of hydropower projects[S].Beijing:China Planning Publishing House,2003.
[20]中华人民共和国水利部.SL212-2012水工预应力锚固设计规范[S].北京:中国水利水电出版社,2012.Ministry of Water Resources of the People’s Republic of China.Design code for prestressed anchorage of hydraulic engineering SL212-2012[S].Beijing:China Water Resources and Hydropower Publishing House,2012.
[21]The British Standard Institution.BS EN 1537:2013Execution of special geotechnical works-Ground anchors[S].[S.l.]:BSI Standard Publication,2013.