高土石坝坝坡地震稳定分析研究
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摘要
采用有限元动力时程稳定和变形分析方法,对不同高度大坝坝坡稳定进行分析,开展了最危险滑弧确定方法、地震动持时对稳定和变形的影响、滑弧位置和深度以及坝坡加固范围的研究。结果表明:拟静力法采用规范建议的加速度分布系数不能反映高土石坝实际地震反应规律,计算得到的最危险滑弧较深且滑动范围偏大,不利于确定坝坡的加固范围;坝坡在地震过程中,最小安全系数与最大滑动量对应的滑弧并不一致且是不断变化的,有限元动力法计算坝坡稳定时,应在每一时刻任意搜索最危险滑弧;地震持时对坝坡安全系数影响不大,但对滑动量有较大影响;不同滑弧深度对坝坡安全系数有较大影响,存在一个临界深度,当滑弧超过临界深度时,坝坡安全系数大于1.0;坝坡稳定安全性评价需要综合考虑安全系数与变形的计算结果。根据计算结果,建议了坝坡加固的范围。
By using the dynamic finite element stability and deformation method,the definite methods for the most dangerous sliding surface,the influences of seismic duration and depth of sliding surface on slope stability and deformation as well as the reinforcement range of dam slopes are studied.The results show that by means of the pseudo-static method,the slip circle corresponding to the minimum safety factor is deeper and the slip range is larger owing to the fact that the acceleration distribution coefficient suggested by the Chinese Code does not match the seismic response of dams.It is not helpful for determining the reinforcement range of dam slopes.During the earthquake history,the potential sliding surface varies with the time history,and it should be arbitrarily searched by using the dynamic finite element method.The potential sliding surface corresponding to the minimum safety factor is different from the maximum slippage.The estimation of the stability safety of dam slopes should combine the safety factor with the deformation.The reinforcement range of dam slopes is suggested according to the calculated results.
By using the dynamic finite element stability and deformation method,the definite methods for the most dangerous sliding surface,the influences of seismic duration and depth of sliding surface on slope stability and deformation as well as the reinforcement range of dam slopes are studied.The results show that by means of the pseudo-static method,the slip circle corresponding to the minimum safety factor is deeper and the slip range is larger owing to the fact that the acceleration distribution coefficient suggested by the Chinese Code does not match the seismic response of dams.It is not helpful for determining the reinforcement range of dam slopes.During the earthquake history,the potential sliding surface varies with the time history,and it should be arbitrarily searched by using the dynamic finite element method.The potential sliding surface corresponding to the minimum safety factor is different from the maximum slippage.The estimation of the stability safety of dam slopes should combine the safety factor with the deformation.The reinforcement range of dam slopes is suggested according to the calculated results.
引文
[1]DL5073—2000水工建筑物抗震设计规范[S].2000.(DL5073—2000 Specifications for seismic design of hydraulic structures[S].2000.(in Chinese))
[2]CHANG C J,CHEN W F,YAO James T P.Seismic displacement in slopes by limit analysis[J].Journal of Geotechnical Engineering,ASCE,1984,110(7):860–874.
[3]BAKER R,GARBER M.Theoretical analysis of the stability of slopes[J].Géotechnique,1978,28(4):395–411.
[4]LESHCHINSKY D.Slope stability analysis:Generalized approach[J].Journal of Geotechnical Engineering,ASCE,1990,116(5):851–867.
[5]LESHCHINSKY D,SAN K C.Pseudostatic seismic stability of slopes:design charts[J].Journal of Geotechnical Engineering,ASCE,1994,120(9):1514–1532.
[6]SAN K C,LESHCHINSKY D.Seismic slope stability analysis:Pseudo-static generalized method[J].Soils and Foundations,1994,34(2):73–77.
[7]栾茂田,李湛,范庆来.土石坝拟静力抗震稳定性分析与坝坡地震滑移量估算[J].岩土力学,2007,28(2):224–230.(LUAN Mao-tian,LI Zhan,FAN Qing-lai.Analysis and evaluation of pseudo-static aseismic stability and seism-induced sliding movement of earth-rock dams[J].Rock and Soil Mechanics,2007,28(2):224–230.(in Chinese))
[8]NEWMARK N M.Effects of earthquakes on dams and embankments[J].Géotechnique,1965,15(2):139–160.
[9]GB50267—97核电厂抗震设计规范[S].1997.(GB50267—97 Code for seismic design of nuclear power plants[S].1997.(in Chinese))
[10]李红军,迟世春,钟红,等.考虑时程竖向加速度的Newmark滑块位移法[J].岩土力学,2007,28(11):2385–2390.(LI Hong-jun,CHI Shi-chun,ZHONG Hong,et al.Effects of vertical acceleration time-histories on Newmark sliding block analyses[J].Rock and Soil Mechanics,2007,28(11):2385–2390.(in Chinese))
[11]李红军,迟世春,林皋.高心墙堆石坝坝坡加筋抗震稳定分析[J].岩土工程学报,2007,29(12):1881–1887.(LI Hong-jun,CHI Shi-chun,LIN Gao.Aseismic stability analysis for reinforced slopes of high core rock-fill dams[J].Chinese Journal of Geotechnical Engineering,2007,29(12):1881–1887.(in Chinese))
[12]陈生水,霍家平,章为民.汶川“5.12”地震对紫坪铺混凝土面板堆石坝的影响及原因分析[J].岩土工程学报,2008,30(6):795–801.(CHEN Sheng-shui,HUO Jia-ping,ZHANG Wei-ming.Analysis of effects of“5.12”Wenchuan Earthquake on Zipingpu Concrete Face Rock-fill Dam[J].Chinese Journal of Geotechnical Engineering,2008,30(6):795–801.(in Chinese))
[13]孔宪京,娄树莲,邹德高,等.筑坝堆石料的等效动剪切模量与等效阻尼比[J].水利学报,2001(8):20–25.(KONG Xian-jing,LOU Shu-lian,ZOU De-gao,et al.The equivalent dynamic shear modulus and equivalent damping ratio of the rockfill for dam[J].Journal of Hydraulic Engineering.2001(8):20–25.(in Chinese))
[14]邹德高,孔宪京,徐斌.Geotechnical Dynamic NonlinearAnalysis-GEODYNA使用说明[R].大连:大连理工大学土木水利学院工程抗震研究所,2003.(ZOU De-gao,KONG Xian-jing.Geotechnical Dynamic NonlinearAnalysis-GEODYNA user manual[R].DaLian:The Earthquake Engineering Research Institute,Dalian University of Technology,2003.(in Chinese))
[15]孔宪京,邹德高,邓学晶,等.高土石坝综合抗震措施及其效果的验算[J].水利学报,2006,37(12):1489–1495.(KONG Xian-jing,ZOU De-gao,DENG Xue-jing,et al.Comprehensive earthquake resistant measure of high earth-rockfill dams and effectiveness verification[J].Journal of Hydraulic Engineering,2006,37(12):1489–1495.(in Chinese))
[2]CHANG C J,CHEN W F,YAO James T P.Seismic displacement in slopes by limit analysis[J].Journal of Geotechnical Engineering,ASCE,1984,110(7):860–874.
[3]BAKER R,GARBER M.Theoretical analysis of the stability of slopes[J].Géotechnique,1978,28(4):395–411.
[4]LESHCHINSKY D.Slope stability analysis:Generalized approach[J].Journal of Geotechnical Engineering,ASCE,1990,116(5):851–867.
[5]LESHCHINSKY D,SAN K C.Pseudostatic seismic stability of slopes:design charts[J].Journal of Geotechnical Engineering,ASCE,1994,120(9):1514–1532.
[6]SAN K C,LESHCHINSKY D.Seismic slope stability analysis:Pseudo-static generalized method[J].Soils and Foundations,1994,34(2):73–77.
[7]栾茂田,李湛,范庆来.土石坝拟静力抗震稳定性分析与坝坡地震滑移量估算[J].岩土力学,2007,28(2):224–230.(LUAN Mao-tian,LI Zhan,FAN Qing-lai.Analysis and evaluation of pseudo-static aseismic stability and seism-induced sliding movement of earth-rock dams[J].Rock and Soil Mechanics,2007,28(2):224–230.(in Chinese))
[8]NEWMARK N M.Effects of earthquakes on dams and embankments[J].Géotechnique,1965,15(2):139–160.
[9]GB50267—97核电厂抗震设计规范[S].1997.(GB50267—97 Code for seismic design of nuclear power plants[S].1997.(in Chinese))
[10]李红军,迟世春,钟红,等.考虑时程竖向加速度的Newmark滑块位移法[J].岩土力学,2007,28(11):2385–2390.(LI Hong-jun,CHI Shi-chun,ZHONG Hong,et al.Effects of vertical acceleration time-histories on Newmark sliding block analyses[J].Rock and Soil Mechanics,2007,28(11):2385–2390.(in Chinese))
[11]李红军,迟世春,林皋.高心墙堆石坝坝坡加筋抗震稳定分析[J].岩土工程学报,2007,29(12):1881–1887.(LI Hong-jun,CHI Shi-chun,LIN Gao.Aseismic stability analysis for reinforced slopes of high core rock-fill dams[J].Chinese Journal of Geotechnical Engineering,2007,29(12):1881–1887.(in Chinese))
[12]陈生水,霍家平,章为民.汶川“5.12”地震对紫坪铺混凝土面板堆石坝的影响及原因分析[J].岩土工程学报,2008,30(6):795–801.(CHEN Sheng-shui,HUO Jia-ping,ZHANG Wei-ming.Analysis of effects of“5.12”Wenchuan Earthquake on Zipingpu Concrete Face Rock-fill Dam[J].Chinese Journal of Geotechnical Engineering,2008,30(6):795–801.(in Chinese))
[13]孔宪京,娄树莲,邹德高,等.筑坝堆石料的等效动剪切模量与等效阻尼比[J].水利学报,2001(8):20–25.(KONG Xian-jing,LOU Shu-lian,ZOU De-gao,et al.The equivalent dynamic shear modulus and equivalent damping ratio of the rockfill for dam[J].Journal of Hydraulic Engineering.2001(8):20–25.(in Chinese))
[14]邹德高,孔宪京,徐斌.Geotechnical Dynamic NonlinearAnalysis-GEODYNA使用说明[R].大连:大连理工大学土木水利学院工程抗震研究所,2003.(ZOU De-gao,KONG Xian-jing.Geotechnical Dynamic NonlinearAnalysis-GEODYNA user manual[R].DaLian:The Earthquake Engineering Research Institute,Dalian University of Technology,2003.(in Chinese))
[15]孔宪京,邹德高,邓学晶,等.高土石坝综合抗震措施及其效果的验算[J].水利学报,2006,37(12):1489–1495.(KONG Xian-jing,ZOU De-gao,DENG Xue-jing,et al.Comprehensive earthquake resistant measure of high earth-rockfill dams and effectiveness verification[J].Journal of Hydraulic Engineering,2006,37(12):1489–1495.(in Chinese))
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