雅砻江两河口水电站地下厂房围岩稳定性研究
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摘要
两河口水电站是雅砻江中下游的控制性龙头电站工程,坝址区位于四川省雅江县县城之北约25km。水电站拟装机容量3000MW,地下厂房布置于雅砻江右岸山体中,由平行布置的主厂房、主变室、尾水洞三大地下洞室组成,地下洞室高25~78m,跨度19~28m,围岩岩性主要为变质砂岩夹粉砂质板岩,断裂裂隙较发育。处于高地应力条件下的裂隙岩体在大跨度开挖下,地下洞室围岩稳定性问题是主要的工程地质问题。因此,围岩稳定性研究对厂房洞室围岩支护设计及施工方案的确定,确定厂房施工期及运行期安全具有重要的实际意义。
本文在厂房区围岩地质条件、岩体结构特性、岩体质量等研究基础上,采用数值模拟、块体分析(SASW)等手段,对地下洞室群的整体变形稳定性及块体稳定性进行了研究,取得了如下主要认识:
(1)研究了厂房区围岩的工程地质条件及岩体结构特征。厂房区地层为三叠系上统两河口组中、下段(T3lh2、T3lh1),岩性以砂岩夹粉砂质板岩为主,断裂裂隙发育,岩体结构主要以中厚层~互层状结构为主;厂房区地下水较为丰富,地应力达25MPa,属于中高地应力地区。
(2)采用定性和定量相结合的方法,对厂房区岩体质量进行了综合评价,结果表明厂房区围岩以Ⅲ1、Ⅲ2级为主,其中Ⅲ1级围岩约占80%,Ⅲ2级围岩主要分布于f12和f4断层之间和地下洞室北端墙附近。
(3)在对工程区岩体结构模型进行概化的基础上,采用Flac3D模拟了地下洞室开挖后围岩的应力、变形分布和动态变化特征。洞室开挖后,围岩向洞壁临空方向挤压,使得洞壁内鼓变形。由于受区域小断层的影响,厂房内水平方向变形、竖直方向变形均比较大,尤其是断层带与厂房相交部位产生错动挤压破坏,最大变形量值在8cm左右。
(4)利用块体稳定性分析软件SASW软件对洞室不同构造部位的潜在块体进行稳定性分析,评价了块体对地下洞室围岩局部稳定性的影响。结果表明:厂房内小断层与轴线大角度相交,对厂房整体稳定有利,但应注意其与优势裂隙组裂隙组合对厂房局部稳定的不利影响,应及时锚固。
Lianghekou Hydropower Station is a controlling hydroelectric power station of the middle and low reaches of Yalong River., the whole cascade Yalong tremendous impact on the development of power plants.
The Lianghekou Hydropower Station which is 3000MW-installed capacity, is planned to adopt the form of the underground factory, building, which is formed by three large cavities. The three main underground cavities were disposed parallelly and the axes direction is N3°E. As a whole the rock quality of the hill is well. But because of the tectonic movements and epigene-action, joints and faults, which reduce the hardness of the rock body, haveincised the rock body. Moreover, the cavities have excavated in big span and in groups, which resulted in the biggish adjust of the rock body stress and displacement,and this adjust maybe lead to destroy in rock mass. Thereby, the project can't go on or the cavities can't work normally.On basis of comprehensive analysis of plenty of in-situ investigations and former findings in Lianghekou, the author established complex rock mass model by description of rock mass conditions. Then following basic methods for evaluating the stability of underground cavern group's surrounding rock combining whole deformation with local blocks stability evaluation, the findings can be obtained as follows:
(1)According to a lot of field work with measuring data and indoor statistical analysis,this paper has studied the engineering geological characteristic and classified the type of rock structure in the dam area.
(2) After obtaining above-mentioned materials, synthetical classification has been figured out based on quantitative analysis and contrast synthesis.Also mechanics parameters for different rock types have been brought forward according to the synthetical analysis of field experiments data together with rock mass quality classification indexes.
(3) Based on the conceptual model of rock mass structure in the engineering area, Flac3D is used to simulate stress, strain and plastic zone distribution and dynamic characteristics of the Surrounding rocks of underground cavern groups and diversion generating system after excavation with fundamental theories and methods of complex rock mass modeling. And engineering effects of controlled structure planes are analyzed and summarized in order to provide basic data and theory for evaluating systematically the stability and supporting designs of underground cavern groups and diversion generating system.
(4) Based on the simplified geology structure, Stability of potential blocks at different constructional position surrounding rock mass is calculated and sensitivity to influencing factors of the blocks in surrounding rock mass is analyzed using software SASW.
本文在厂房区围岩地质条件、岩体结构特性、岩体质量等研究基础上,采用数值模拟、块体分析(SASW)等手段,对地下洞室群的整体变形稳定性及块体稳定性进行了研究,取得了如下主要认识:
(1)研究了厂房区围岩的工程地质条件及岩体结构特征。厂房区地层为三叠系上统两河口组中、下段(T3lh2、T3lh1),岩性以砂岩夹粉砂质板岩为主,断裂裂隙发育,岩体结构主要以中厚层~互层状结构为主;厂房区地下水较为丰富,地应力达25MPa,属于中高地应力地区。
(2)采用定性和定量相结合的方法,对厂房区岩体质量进行了综合评价,结果表明厂房区围岩以Ⅲ1、Ⅲ2级为主,其中Ⅲ1级围岩约占80%,Ⅲ2级围岩主要分布于f12和f4断层之间和地下洞室北端墙附近。
(3)在对工程区岩体结构模型进行概化的基础上,采用Flac3D模拟了地下洞室开挖后围岩的应力、变形分布和动态变化特征。洞室开挖后,围岩向洞壁临空方向挤压,使得洞壁内鼓变形。由于受区域小断层的影响,厂房内水平方向变形、竖直方向变形均比较大,尤其是断层带与厂房相交部位产生错动挤压破坏,最大变形量值在8cm左右。
(4)利用块体稳定性分析软件SASW软件对洞室不同构造部位的潜在块体进行稳定性分析,评价了块体对地下洞室围岩局部稳定性的影响。结果表明:厂房内小断层与轴线大角度相交,对厂房整体稳定有利,但应注意其与优势裂隙组裂隙组合对厂房局部稳定的不利影响,应及时锚固。
Lianghekou Hydropower Station is a controlling hydroelectric power station of the middle and low reaches of Yalong River., the whole cascade Yalong tremendous impact on the development of power plants.
The Lianghekou Hydropower Station which is 3000MW-installed capacity, is planned to adopt the form of the underground factory, building, which is formed by three large cavities. The three main underground cavities were disposed parallelly and the axes direction is N3°E. As a whole the rock quality of the hill is well. But because of the tectonic movements and epigene-action, joints and faults, which reduce the hardness of the rock body, haveincised the rock body. Moreover, the cavities have excavated in big span and in groups, which resulted in the biggish adjust of the rock body stress and displacement,and this adjust maybe lead to destroy in rock mass. Thereby, the project can't go on or the cavities can't work normally.On basis of comprehensive analysis of plenty of in-situ investigations and former findings in Lianghekou, the author established complex rock mass model by description of rock mass conditions. Then following basic methods for evaluating the stability of underground cavern group's surrounding rock combining whole deformation with local blocks stability evaluation, the findings can be obtained as follows:
(1)According to a lot of field work with measuring data and indoor statistical analysis,this paper has studied the engineering geological characteristic and classified the type of rock structure in the dam area.
(2) After obtaining above-mentioned materials, synthetical classification has been figured out based on quantitative analysis and contrast synthesis.Also mechanics parameters for different rock types have been brought forward according to the synthetical analysis of field experiments data together with rock mass quality classification indexes.
(3) Based on the conceptual model of rock mass structure in the engineering area, Flac3D is used to simulate stress, strain and plastic zone distribution and dynamic characteristics of the Surrounding rocks of underground cavern groups and diversion generating system after excavation with fundamental theories and methods of complex rock mass modeling. And engineering effects of controlled structure planes are analyzed and summarized in order to provide basic data and theory for evaluating systematically the stability and supporting designs of underground cavern groups and diversion generating system.
(4) Based on the simplified geology structure, Stability of potential blocks at different constructional position surrounding rock mass is calculated and sensitivity to influencing factors of the blocks in surrounding rock mass is analyzed using software SASW.
引文
[1]国家电力公司成都勘测设计研究院.四川省雅砻江两河口水电站预可行性研究报告(工程地质)[R],2007.6
[2]沈军辉.沈中超等,两河口水电站枢纽区工程边坡稳定性地质研究报告[R],2008.5
[3]祝怀田.两河口水电站引水进口高边坡稳定性评价及支护方案研究[D].成都理工大学硕士论文,2009.6
[4]朱容辰.雅砻江两河口水电站坝址区边坡卸荷分带与岩体质量分级研究[D].成都理工大学硕士论文,2009.6
[5]薛守义,刘汉东.岩体工程学科性质透视[M].郑州:黄河水利出版社,2002.
[6]聂德新,杨建宏,崔长武等.岩体结构、岩体质量及可利用性研究[M].北京:地质出版社,2008.
[7]孙玉科.工程地质学发展与创新思路探讨之五——岩体结构的发现及其理论意义[J].岩土工程界,2002,6(1):30.
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[11]杜时贵.岩体结构面抗剪强度经验估算[M].北京:地震出版社,2005.
[12]黄志全,李华晔,马莎等.岩石边坡块状结构岩体稳定性分析和可靠性评价[J].岩石力学与工程学报,2004,23(24):4200-4205.
[13]胡卸文,钟沛林,任志刚.岩体块度指数及其工程意义[J].水利学报,2002(3):80-83.
[14]贾洪彪等.岩体结构面三维网络模拟理论与工程应用[M].北京:科学出版社,2008.
[15]黄润秋等.复杂岩体结构精细描述及其工程应用[M].北京:科学出版社,2004.
[16]肖明.地下洞室施工开挖三维动态过程数值模拟分析[J].岩土工程学报.2000.22(4):421-425
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[19]高谦.地下大跨度采场围岩突变失稳风险预测[J].岩土工程学报.2000.22 (5):523-527
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[22]陈精一等.电脑辅助工程分析ANSYS使用指南[M].中国铁道出版社.2001.1-10
[23]陶立娜等.楔形块体的动力稳定分析[J].四川大学学报(工程科学版).第34卷.第3期,2002.5.
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[25]曾静,盛谦,廖红建等.佛子岭水水电站地下厂房施工开挖过程的F'LAC3D数值模拟[J].岩土力学,2006 27(4):637642.
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[29]董小卓.抽水蓄能电站地下厂房洞室群围岩稳定性分析,河海大学硕士论文,2007.5
[30]林宗元.岩土工程勘察设计手册[S].辽宁科学技术出版社,1996
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[2]沈军辉.沈中超等,两河口水电站枢纽区工程边坡稳定性地质研究报告[R],2008.5
[3]祝怀田.两河口水电站引水进口高边坡稳定性评价及支护方案研究[D].成都理工大学硕士论文,2009.6
[4]朱容辰.雅砻江两河口水电站坝址区边坡卸荷分带与岩体质量分级研究[D].成都理工大学硕士论文,2009.6
[5]薛守义,刘汉东.岩体工程学科性质透视[M].郑州:黄河水利出版社,2002.
[6]聂德新,杨建宏,崔长武等.岩体结构、岩体质量及可利用性研究[M].北京:地质出版社,2008.
[7]孙玉科.工程地质学发展与创新思路探讨之五——岩体结构的发现及其理论意义[J].岩土工程界,2002,6(1):30.
[8]孙玉科,古迅.赤平极射投影在岩体工程地质力学的应用[M].北京:科学出版社,1980.
[9]孙广忠.岩体结构力学[M].北京:科学出版社,1988.
[10]杜时贵.岩体结构面的工程性质[M].北京:地震出版社,1999.
[11]杜时贵.岩体结构面抗剪强度经验估算[M].北京:地震出版社,2005.
[12]黄志全,李华晔,马莎等.岩石边坡块状结构岩体稳定性分析和可靠性评价[J].岩石力学与工程学报,2004,23(24):4200-4205.
[13]胡卸文,钟沛林,任志刚.岩体块度指数及其工程意义[J].水利学报,2002(3):80-83.
[14]贾洪彪等.岩体结构面三维网络模拟理论与工程应用[M].北京:科学出版社,2008.
[15]黄润秋等.复杂岩体结构精细描述及其工程应用[M].北京:科学出版社,2004.
[16]肖明.地下洞室施工开挖三维动态过程数值模拟分析[J].岩土工程学报.2000.22(4):421-425
[17]于学馥,郑颖人.地下工程围岩稳定分析[M].北京.煤炭工业出版社.1983
[18]凌贤长.岩体力学研究的若干问题[J].哈尔滨建筑大学学报.1998.31(4):118-123
[19]高谦.地下大跨度采场围岩突变失稳风险预测[J].岩土工程学报.2000.22 (5):523-527
[20]卡曹罗夫著.聂孟荀译.岩石力学[M].北京煤炭工业出版社.1985
[21]陈剑平.岩体随机不连续面三维网络数值模拟技术[J].岩土工程学报.2001.23(4)
[22]陈精一等.电脑辅助工程分析ANSYS使用指南[M].中国铁道出版社.2001.1-10
[23]陶立娜等.楔形块体的动力稳定分析[J].四川大学学报(工程科学版).第34卷.第3期,2002.5.
[24] Barton N.,Lien R.&Lunde J. Engineering classification tunnel support of rock masses for design of the tunnel support. Rock Mechanics.1974. 6(4).
[25]曾静,盛谦,廖红建等.佛子岭水水电站地下厂房施工开挖过程的F'LAC3D数值模拟[J].岩土力学,2006 27(4):637642.
[26] Chen Z Y,et al A three-dimensional slope stability analysis method using the upper bound theorem. PartⅡNumerical Approaches,Applications and extensions[J]. International Journal of Rock Mechnics and Mining Sciences,2001,38:379-397.
[27]潘别桐,黄润秋.工程地质数值法[M].北京:地质出版社,1994.
[28] FLAC3D,Fast Lagrangian Analysis of Continua in 3 Dimensions,Version 2.0,User’sManual, Itasca Consulting Group, Inc. USA.
[29]董小卓.抽水蓄能电站地下厂房洞室群围岩稳定性分析,河海大学硕士论文,2007.5
[30]林宗元.岩土工程勘察设计手册[S].辽宁科学技术出版社,1996
[31]巨能攀.高边墙大跨度地下洞室群围岩稳定性评价及支护研究—以糯扎渡水电站为例[D],成都理工大学博士学位论文, 2006.
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