粘土防渗尾矿库地震永久位移数值模拟
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摘要
我国目前的防渗尾矿库数量越来越多,但对其动力分析相对较少。结合工程实际,使用FLAC2D软件建立了有限差分数值模型,对采用粘土垫层防渗的尾矿库进行二维地震动力响应分析,并将计算得到的坝顶最大水平位移与传统简化方法的计算结果进行了对比分析。计算结果表明,由于数值分析考虑了尾矿坝对地震波的放大效应,通过有限差分数值模型计算的水平位移比简化方法的计算结果大60%。参数分析表明:防渗垫层的抗剪强度对于尾矿库动力响应影响较大,其虽有一定隔震作用,使得防渗层上部的最大水平加速度低于其下部的最大水平加速度约5%~30%,但随着防渗垫层抗剪强度的降低,尾矿库的失稳模式由经过尾矿内部的圆弧形滑动向经过防渗层的楔形滑动转变,尾矿库的屈服加速度显著降低,永久水平位移从小于5cm增加到近70cm,可能造成震陷等灾害。该分析方法和结果对于地震区防渗尾矿库工程的设计有一定的参考价值。
The quantity of anti-seepage tailing ponds is increasing in China,but the corresponding dynamic analysis is relatively less. Combined with engineering practice,a finite difference numerical model was established by FLAC2 D software. Two-dimensional seismic dynamic response analysis was conducted on clay-lined anti-seepage tailing pond,and the calculation result of maximum horizontal displacement in dam crest was comparatively analyzed with that of traditional simplified method. It showed that because the numerical analysis considered the magnification effect of tailing dam to seismic wave,the horizontal displacement calculated by the finite difference numerical model was approximately 60% larger than that by simplified method. The parameters analysis showed that the shear strength of bottom clay anti-seepage liner had a significant impact on the dynamic responses of tailing pond. Although the clay anti-seepage liner had a certain isolation effect,which made the maximum horizontal acceleration above the clay anti-seepage liner being 5%-30% smaller that under the liner,but with the decreasein shear strength of bottom clay anti-seepage liner,the instability mode of tailing pond transferred from the circular arc sliding through the inside of tailing to the wedge sliding through the clay anti-seepage liner. The yield acceleration of tailing pond decreased obviously,and the permanent horizontal displacement increased from less than 5cm to nearly 70 cm,which might cause earthquake subsidence hazard. The analysis methods and results has a certain reference value for the design of anti-seepage tailing pond in earthquake zones.
The quantity of anti-seepage tailing ponds is increasing in China,but the corresponding dynamic analysis is relatively less. Combined with engineering practice,a finite difference numerical model was established by FLAC2 D software. Two-dimensional seismic dynamic response analysis was conducted on clay-lined anti-seepage tailing pond,and the calculation result of maximum horizontal displacement in dam crest was comparatively analyzed with that of traditional simplified method. It showed that because the numerical analysis considered the magnification effect of tailing dam to seismic wave,the horizontal displacement calculated by the finite difference numerical model was approximately 60% larger than that by simplified method. The parameters analysis showed that the shear strength of bottom clay anti-seepage liner had a significant impact on the dynamic responses of tailing pond. Although the clay anti-seepage liner had a certain isolation effect,which made the maximum horizontal acceleration above the clay anti-seepage liner being 5%-30% smaller that under the liner,but with the decreasein shear strength of bottom clay anti-seepage liner,the instability mode of tailing pond transferred from the circular arc sliding through the inside of tailing to the wedge sliding through the clay anti-seepage liner. The yield acceleration of tailing pond decreased obviously,and the permanent horizontal displacement increased from less than 5cm to nearly 70 cm,which might cause earthquake subsidence hazard. The analysis methods and results has a certain reference value for the design of anti-seepage tailing pond in earthquake zones.
引文
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[2]Seed H B and Martin G R.The seismic coefficient in earth dam design[J].Journal of the Soil Mechanical and Foundation Division,1966,92(3):25-58
[3]Makdisi F I and Seed H B.Simplified procedure for estimating dam and embankment earthquake-induced deformation[J].Journal 0f the Geo technical Engineering Division,1978,104(7):849-867
[4]Chakraborty D,Choudhury D.Investigation of the behavior of tailings earthen dam under seismic conditions[J].American Journal of Engineering and Applied Sciences,2009,2(3):559
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[6]陈云敏,柯瀚,凌道盛.城市垃圾填埋体的动力特性及地震响应[J]土木工程学报,2002,35(3):66-71CHEN Yun-min,KE Han,LING Dao-sheng.Dynamic properties and seismic response of municipal solid waste[J].China Civil Engineering Journal,2002,35(3):66-71
[7]刘君,孔宪京.卫牛填埋场复合边坡地震稳定性和永久变形分析[J]岩土力学,2005,25(5):778-782LIU Jun,KONG Xian-jing.Seismic stability and permanent displacement analysis of a solid waste landfill slope containing geomembrane[J].Rock and Soil Mechanics,2005,25(5):778-782
[8]邓学晶,邹德高,孔宪京.城市垃圾填埋场振动台试验的数值模拟研究[J].岩土力学,2012,33(2):623-627DENG Xue-jing,ZOU Gao-de,KONG Xian-jing.Numerical simulation for shaking-table test of municipal waste landfills[J].Rock and Soil Mechanics,2012,33(2):623-627
[9]GB 50863-2013,尾矿设施设计规范[S].2013
[10]李亚俊,张志军,刘玄钊,等.某尾矿坝稳定性的FLAC模拟分析[J].南华大学学报:自然科学版,2013,27(4):23-27LI Ya-jun,ZHANG Zhi-jun,LIU Xuan-zhao,et al.The simulation and stability analysis on a certain tailings dam by FLAC software[J].Journal of University of South China(Science and Technology),2013,27(4):23-27
[11]Sun J I,Golesorkhi R,Seed H B.Dynamic modulus and damping ratios for cohesive soils[R].Earthquake Engineering Research Center,University of California,1988.
[12]Kuhlemeyer R L.Lysmer J.Finite element method accuracy for wave propagation problems[J].Journal of Soil Mechanics&Foundations Div,1973,99
[13]FLAC-Fast Lagrangian Analysis of Continua,Version.7.0,User's Manual[M].Itasca Consulting Group,Inc.,2011.Dynamic Analysis:161-170
[2]Seed H B and Martin G R.The seismic coefficient in earth dam design[J].Journal of the Soil Mechanical and Foundation Division,1966,92(3):25-58
[3]Makdisi F I and Seed H B.Simplified procedure for estimating dam and embankment earthquake-induced deformation[J].Journal 0f the Geo technical Engineering Division,1978,104(7):849-867
[4]Chakraborty D,Choudhury D.Investigation of the behavior of tailings earthen dam under seismic conditions[J].American Journal of Engineering and Applied Sciences,2009,2(3):559
[5]张栋,吴宗之,蔡嗣经.尾矿库地震液化机理及抗震评估指标体系研究[J].中国安全生产科学技术,2010,6(6):17-22ZHANG Dong,WU Zong-zhi,CAI Shi-jing.Discussion on tailings reservoir dam failure risk assessment index system under seismic conditions[J].Journal of Safety Science and Technology,2010,6(6):17-22
[6]陈云敏,柯瀚,凌道盛.城市垃圾填埋体的动力特性及地震响应[J]土木工程学报,2002,35(3):66-71CHEN Yun-min,KE Han,LING Dao-sheng.Dynamic properties and seismic response of municipal solid waste[J].China Civil Engineering Journal,2002,35(3):66-71
[7]刘君,孔宪京.卫牛填埋场复合边坡地震稳定性和永久变形分析[J]岩土力学,2005,25(5):778-782LIU Jun,KONG Xian-jing.Seismic stability and permanent displacement analysis of a solid waste landfill slope containing geomembrane[J].Rock and Soil Mechanics,2005,25(5):778-782
[8]邓学晶,邹德高,孔宪京.城市垃圾填埋场振动台试验的数值模拟研究[J].岩土力学,2012,33(2):623-627DENG Xue-jing,ZOU Gao-de,KONG Xian-jing.Numerical simulation for shaking-table test of municipal waste landfills[J].Rock and Soil Mechanics,2012,33(2):623-627
[9]GB 50863-2013,尾矿设施设计规范[S].2013
[10]李亚俊,张志军,刘玄钊,等.某尾矿坝稳定性的FLAC模拟分析[J].南华大学学报:自然科学版,2013,27(4):23-27LI Ya-jun,ZHANG Zhi-jun,LIU Xuan-zhao,et al.The simulation and stability analysis on a certain tailings dam by FLAC software[J].Journal of University of South China(Science and Technology),2013,27(4):23-27
[11]Sun J I,Golesorkhi R,Seed H B.Dynamic modulus and damping ratios for cohesive soils[R].Earthquake Engineering Research Center,University of California,1988.
[12]Kuhlemeyer R L.Lysmer J.Finite element method accuracy for wave propagation problems[J].Journal of Soil Mechanics&Foundations Div,1973,99
[13]FLAC-Fast Lagrangian Analysis of Continua,Version.7.0,User's Manual[M].Itasca Consulting Group,Inc.,2011.Dynamic Analysis:161-170
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