岩溶区地下厂房洞室群围岩渗流效应分析
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摘要
岩溶渗流效应包括渗流场的力学效应和岩体软化效应。针对富水岩溶区地下工程的特殊赋存环境,提出了岩溶地下厂房3维渗流场力学效应耦合计算方法和基于强度折减原理的渗流软化效应分析方法。计算分析了不同工况、围岩不同软化程度下洞周变形破坏规律。提出地下洞群整体软化安全系数的确定方法,定量评价不同工况下地下厂房洞群围岩整体相对稳定状态,分析岩溶渗流软化效应对围岩稳定的影响。工程实例表明:考虑渗流场力学效应时,开挖完毕围岩变形都明显增大,变化规律与监测相符;对比无渗流场、考虑施工期渗流场和考虑运行期渗流场各工况的整体软化安全系数变化规律发现,渗流场软化效应显著;运行期正常蓄水后,地下水位的提高引致厂区渗流场调整,对围岩整体稳定存在明显影响。整体软化安全系数能够有效地反映渗流软化效应对岩溶地下厂房围岩稳定的影响,为岩溶区地下厂房工程优化设计、施工监测及安全运行评价提供有益参考。
Mechanical effect and softening effect are two typical effects on underground structures subjected to seepage flow at Karst region.For underground engineering at Karst region with rich groundwater,a finite element method coupling mechanical effect of seepage to simulate excavation and support construction was proposed.And a strength reduction methodology for softening effect analysis of seepage was also put forward based on the identification of the general softening safety factor of underground caverns.The distribution of deformation and damage around openings was calculated and analyzed subjected to different seepage conditions and different softening degrees of rockmass strength.The softening safety factors were identified to quantificationally assess the stability of the caverns related to different calculation conditions and to analyze the impact of softening effect of seepage on the stability of the surrounding rock.The calculation results illustrated with a practical excavation project at Karst region showed that the displacements around the openings evidently increase when the mechanical effect of seepage is coupled to excavation simulation.It was indicated that the softening effect is of significance on the surrounding rock by comparison of softening safety factors under different seepage conditions.For the underground caverns,the growing of groundwater level would lead to unsteady seepage flow,which has significant impact on the stability of the rockmass.The softening safety factor is able to characterize the effect of seepage on the surrounding rock stability of underground caverns that would be helpful to well design,construction monitoring and safety assessment of underground engineering at Karst region.
Mechanical effect and softening effect are two typical effects on underground structures subjected to seepage flow at Karst region.For underground engineering at Karst region with rich groundwater,a finite element method coupling mechanical effect of seepage to simulate excavation and support construction was proposed.And a strength reduction methodology for softening effect analysis of seepage was also put forward based on the identification of the general softening safety factor of underground caverns.The distribution of deformation and damage around openings was calculated and analyzed subjected to different seepage conditions and different softening degrees of rockmass strength.The softening safety factors were identified to quantificationally assess the stability of the caverns related to different calculation conditions and to analyze the impact of softening effect of seepage on the stability of the surrounding rock.The calculation results illustrated with a practical excavation project at Karst region showed that the displacements around the openings evidently increase when the mechanical effect of seepage is coupled to excavation simulation.It was indicated that the softening effect is of significance on the surrounding rock by comparison of softening safety factors under different seepage conditions.For the underground caverns,the growing of groundwater level would lead to unsteady seepage flow,which has significant impact on the stability of the rockmass.The softening safety factor is able to characterize the effect of seepage on the surrounding rock stability of underground caverns that would be helpful to well design,construction monitoring and safety assessment of underground engineering at Karst region.
引文
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[8]Fu Jing,Ding Xiuli,Zhang Lian.Numerical analysis on im-provement of stability of underground grotto group surround-ing rock mass with filling in karst regions[J].Journal ofYangtze River Scientific Research Institute,2006,23(4):47-49.[付敬,丁秀丽,张练.岩溶回填改善地下洞室群围岩稳定性的数值分析[J].长江科学院院报,2006,23(4):47-49.]
[9]Wei Lide,Chen Congxin,Xu Jian,et al.Study on strengthreduction fem considering seepage and bolt[J].ChineseJournal of Rock Mechanics and Engineering,2008,27(supp2):3471-3476.[韦立德,陈从新,徐建,等.考虑渗流和锚固作用的强度折减有限元法研究[J].岩石力学与工程学报,2008,27(增2):3471-3476.]
[10]Xiao Ming.Three-dimensional numerical model of construc-tion process for underground opening[J].Chinese Journal ofGeotechnical Engineering,2000,22(4):421-425.[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.]
[11]Zhao Jian,Lai Miao,Shen Zhenzhong.Improved convertingpermeability coefficient method and variable permeability co-efficient method for seepage calculation in karst region[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(8):1341-1347.[赵坚,赖苗,沈振中.适于岩溶地区渗流场计算的改进折算渗透系数法和变渗透系数法[J].岩土力学与工程学报,2005,24(8):1341-1347.]
[12]Jiang Quan,Feng Xiating,Xiang Tianbing.Discussion onmethod for calculating general safety factor of undergroundcaverns based on strength reduction theory[J].Rock and soilMechanics,2009,30(8):2483-2488.[江权,冯夏庭,向天兵.基于强度折减原理的地下洞室群整体安全系数计算方法探讨[J].岩土力学,2009,30(8):2483-2488.]
[13]Zhang Yuting,Xiao ming,Chen Juntao.The assessment ofpost-earthquake reinforcement measures and the calculationof safety factor for general stability of underground cavernsunder earthquake effect[J].Journal of Sichuan University:Engineering Science Edition,2010,42(5):217-223.[张雨霆,肖明,陈俊涛.地震作用下地下洞室群整体安全系数计算与震后加固效果评价[J].四川大学学报:工程科学版,2010,42(5):217-223.]
[14]云南省牛栏江—滇池补水工程干河泵站主厂房安全监测分析专题报告(南科院泵测[2011]监测17号)[R].南京:南京水利科学研究院,2011.
[2]Wang Jianxiu,Feng Bo,Zhang Xingsheng,et al.Hydraulicfailure mechanism of karst tunnel surrounding rock[J].Chi-nese Journal of Rock Mechanics and Engineering,2010,29(7):1363-1370.[王建秀,冯波,张兴胜,等.岩溶隧道围岩水力破坏机制研究[J].岩石力学与工程学报,2010,29(7):1363-1370.]
[3]Zhao Mingjie,Xu Rong,Xu Xibin.Deformation analysis andmonitoring of surrounding rock during full-face excavation oftunnel in karst regions[J].Journal of Tongji University:Natural Science,2004,32(7):866-871.[赵明阶,徐容,许锡宾.岩溶区全断面开挖隧道围岩变形规律及其监测[J].同济大学学报:自然科学版,2004,32(7):866-871.]
[4]Zhang Wei,Xiao Ming,Fan Guobang.Stress-damage-seepagecoupling analysis of surrounding rock of large-scale under-ground caverns[J].Rock and Soil Mechanics,2008,29(7):1813-1818.[张巍,肖明,范国邦.大型地下洞室群围岩应力-损伤-渗流耦合分析[J].岩土力学,2008,29(7):1813-1818.]
[5]Chen Yifeng,Zhou Chuangbing,Hu Ran,et al.Key issues onseepage flow analysis in large scale hydropower projects[J].Chinese Journal of Geotechnical Engineering,2010,32(9):1448-1454.[陈益峰,周创兵,胡冉,等.大型水电工程渗流分析的若干关键问题研究[J].岩土工程学报,2010,32(9):1448-1454.]
[6]Xu R,Yan F.Karst geology and engineering treatment in theGeheyan Project on the Qingjiang River,China[J].Engi-neering Geology,2004,76(1/2):155-164.
[7]Zhao Mingjie,Xu Rong,Xu Xibin.Deformation modeling ofsurrounding-rock during full-face excavation of tunnel inkarst regions[J].Journal of Tongji University:Natural Sci-ence,2004,32(6):710-715.[赵明阶,徐容,许锡宾.岩溶区全断面开挖隧道围岩变形特性模拟[J].同济大学学报:自然科学版,2004,32(6):710-715.]
[8]Fu Jing,Ding Xiuli,Zhang Lian.Numerical analysis on im-provement of stability of underground grotto group surround-ing rock mass with filling in karst regions[J].Journal ofYangtze River Scientific Research Institute,2006,23(4):47-49.[付敬,丁秀丽,张练.岩溶回填改善地下洞室群围岩稳定性的数值分析[J].长江科学院院报,2006,23(4):47-49.]
[9]Wei Lide,Chen Congxin,Xu Jian,et al.Study on strengthreduction fem considering seepage and bolt[J].ChineseJournal of Rock Mechanics and Engineering,2008,27(supp2):3471-3476.[韦立德,陈从新,徐建,等.考虑渗流和锚固作用的强度折减有限元法研究[J].岩石力学与工程学报,2008,27(增2):3471-3476.]
[10]Xiao Ming.Three-dimensional numerical model of construc-tion process for underground opening[J].Chinese Journal ofGeotechnical Engineering,2000,22(4):421-425.[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.]
[11]Zhao Jian,Lai Miao,Shen Zhenzhong.Improved convertingpermeability coefficient method and variable permeability co-efficient method for seepage calculation in karst region[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(8):1341-1347.[赵坚,赖苗,沈振中.适于岩溶地区渗流场计算的改进折算渗透系数法和变渗透系数法[J].岩土力学与工程学报,2005,24(8):1341-1347.]
[12]Jiang Quan,Feng Xiating,Xiang Tianbing.Discussion onmethod for calculating general safety factor of undergroundcaverns based on strength reduction theory[J].Rock and soilMechanics,2009,30(8):2483-2488.[江权,冯夏庭,向天兵.基于强度折减原理的地下洞室群整体安全系数计算方法探讨[J].岩土力学,2009,30(8):2483-2488.]
[13]Zhang Yuting,Xiao ming,Chen Juntao.The assessment ofpost-earthquake reinforcement measures and the calculationof safety factor for general stability of underground cavernsunder earthquake effect[J].Journal of Sichuan University:Engineering Science Edition,2010,42(5):217-223.[张雨霆,肖明,陈俊涛.地震作用下地下洞室群整体安全系数计算与震后加固效果评价[J].四川大学学报:工程科学版,2010,42(5):217-223.]
[14]云南省牛栏江—滇池补水工程干河泵站主厂房安全监测分析专题报告(南科院泵测[2011]监测17号)[R].南京:南京水利科学研究院,2011.
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