以金沙江溪洛渡水电站库区恩子坪2#滑坡为例,采用宁河地震天津记录数据作为地震动参数,运用离散元程序UDEC(Universal Distinct Element Code)对滑坡在未来地震作用下的响应特征和变形破坏机制进行数值模拟。数值模拟计算结果显示:在地震波作用下,坡体表现出明显的放大效应,其中加速度放大程度最大,位移次之,速度最小;地震波达到峰值后,坡体中的剪应力集中范围和滑带的剪应变均急剧增大,由于剪应变累积效应,变形破坏从滑带前端向尾部传递、扩展;地震结束时,滑坡的稳定性系数已经低于1.0,最大累积位移达到了1.58 m。通过分析数值模拟计算结果可知:运动放大效应、剪应力集中和剪应变累积效应是导致滑坡变形破坏的主要机制,滑坡的失稳模式依然为顺层滑移;滑坡已经失稳破坏,建议采取适当的锚固工程,以降低滑坡在地震作用下失稳堵江的风险,从而保证溪洛渡水库的正常运营。
Abstract
In this research, we simulate the dynamic response characters and failure mechanism of landslide by using the universal distinct element code(UDEC). Enziping landslide No. 2 in the Xiluodu reservoir area of Jinsha river is taken as example, and Ninghe-Tianjin earthquake record as the dynamic parameter. Simulated results show that: 1) under earthquake action, slope shows obvious amplification effect, and amplification effect of acceleration is the biggest, followed by displacement, velocity; 2) area of shear stress concentration and the shear strain of the slip zone dramatically increase after the peak value of the seismic wave, and the deformation and failure extended from the front to the rear of the slip zone due to the accumulation effect of shear strain; 3) safety factor of landslide stability is less than 1.0 and the maximum accumulated displacement is up to 1.58 m when the earthquake stops. Through analyzing calculated data, we conclude that failure mechanism of the landslide results from the combination effect of motion amplification and shear stress concentration and the accumulation of shear strain, and the failure mode remains bedding slide. In light of failure state of the landslide, we give suitable anchoring treatment suggestions for reducing the risk of river closure by earthquake-induced landslide so as to ensure the operation of Xiluodu hydropower project.
关键词
顺层滑坡 /
地震 /
动力响应 /
变形破坏机制 /
离散元法
Key words
bedding landslide /
earthquake /
dynamic response /
deformation and failure mechanism /
discrete element method
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参考文献
[1] 毛彦龙,胡广韬,毛新虎,等.地震滑坡启程剧动的机理研究及离散元模拟[J].工程地质学报,2001,9(1):74-80.
[2] 许 强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探[J].工程地质学报,2008,16(6):721-729.
[3] 殷跃平. 汶川八级地震滑坡高速远程特征分析[J]. 工程地质学报, 2009, 17(2): 153-166.
[4] DAI F C, XU C, YAO X, et al. Spatial Distribution of Landslides Triggered by the 2008 Ms 8.0 Wenchuan Earthquake, China[J]. Journal of Asian Earth Sciences, 2011, 40(4): 883-895.
[5] BOMMER J J, RODRIIGUEZ C E. Earthquake-induced Landslides in Central America[J]. Engineering Geology, 2002, 63: 189-220.
[6] 李维光, 张继春. 地震作用下顺层岩质边坡稳定性的拟静力分析[J]. 山地学报, 2007, 25(2): 184-189.
[7] NEWMARK N M. Effects of Earthquakes on Dams and Embankments[J]. Geotechnique, 1965, 15(2): 139-160.
[8] 刘汉龙, 费 康, 高玉峰. 边坡地震稳定性时程分析方法[J]. 岩土力学, 2003, 24(4): 553-556.
[9] LIN M L,WANG K L.Seismic Slope Behavior in A Large-scale Shaking Table Model Test[J]. Engineering Geology, 2006, 86: 118-133.
[10]洪海春, 徐卫亚. 地震作用下岩质边坡稳定性分析综述[J]. 岩石力学与工程学报, 2005, 24(1): 4827-4836.
[11]毕忠伟, 张 明, 金 峰, 等. 地震作用下边坡的动态响应规律研究[J]. 岩土力学, 2009, 30(增1): 180-183.
[12]王环玲, 徐卫亚. 高烈度区水电工程岩石高边坡三维地震动力响应分析[J]. 岩石力学与工程学报, 2005, 24(增2): 5890-5895.
[13]郑颖人, 叶海林, 黄润秋. 地震边坡破坏机制及其破裂面的分析探讨[J]. 岩石力学与工程学报, 2009, 28(8): 1714-1723.
[14]CUNDALL P A. A Computer Model for Simulating Progressive Large Scale Movements in Blocky Rock System[C]∥ International Society for Rock Mechanics .Proceedings of the International Symposium on Rock Mechanics(Vol. I),Nancy, France, October 4-6 ,1971:128-132.
[15]BHASIN R, KAYNIA A M. Static and Dynamic Simulation of A 700-m High Rock Slope in Western Norway[J]. Engineering Geology, 2004, 71: 213-226.
[16] KVELDSVIK V, KAYNIA A M, NADIM F, et al. Dynamic Distinct-Element Analysis of the 800 m High knes Rock Slope[J]. International Journal of Rock Mechanics and Mining Science, 2009, 46: 686-698.
[17]ZHANG C H, PEKAU O A, JIN F, et al. Application of Distinct Element Method in Dynamic Analysis of High Rock Slopes and Blocky Structures[J]. Soil Dynamics and Earthquake Engineering, 1997, 16: 385-394.
[18]李海波, 肖克强, 刘亚群. 地震荷载作用下顺层岩质边坡安全系数分析[J]. 岩石力学与工程学报, 2007, 26(12): 2385-2394.
[19]谭儒蛟, 李明生, 徐鹏逍, 等. 地震作用下边坡岩体动力稳定性数值模拟[J]. 岩石力学与工程学报, 2009, 28(增2): 3986-3992.
[20]崔芳鹏, 胡瑞林, 殷跃平, 等. 纵横波时差耦合作用的斜坡崩滑效应离散元分析——以北川唐家山滑坡为例[J]. 岩石力学与工程学报, 2010, 29(2): 319-327.
[21]曹琰波, 戴福初, 许 冲, 等. 唐家山滑坡变形运动机制的离散元模拟[J]. 岩石力学与工程学报, 2011,30(增1): 2878-2887.
[22]肖克强, 李海波, 刘亚群, 等. 地震荷载作用下顺层岩体边坡变形特征分析[J]. 岩土力学, 2007, 28(8): 1557-1564.
[23]AL-HOMOUDA A S, TAHTAMONI W. Comparison Between Predictions Using Different Simplified Newmarks’ Block-On-Plane Models and Field Values of Earthquake Induced Displacements[J]. Soil Dynamics and Earthquake Engineering, 2000, 19(2): 73-90.
[24]鲍立新, 冯文凯, 洪望兵, 等. 恩子坪2#滑坡稳定性工程地质研究报告[R]. 成都: 成都理工大学, 2008.
[25]冯文凯, 石豫川, 何 川, 等. 恩子坪2#滑坡特征及稳定性三维数值模拟分析[J]. 水文地质工程地质, 2008, (5): 13-18.
[26]KUHLEMEYER R L, LYSMER J. Finite Element Method Accuracy for Wave Propagation Problems[J]. Journal of the Soil Mechanics and Foundations Division, ASCE, 1973, 99(5): 421-417.
[27]中国地震局分析预报中心. 金沙江白鹤滩水电站坝址设计地震动参数确定报告[R]. 北京: 中国地震局分析预报中心, 2004.
[28]Itasca Consulting Group, Inc.. Universal Distinct Element Code(Version 4.0), User’s Guide[R]. Minneapolis: Itasca Consulting Group, Inc., 2004.
[29]何 铮, 徐卫亚, 石 崇, 等. 顺层岩质高边坡地震变形破坏机制三维数值反演研究[J]. 岩土力学, 2009, 30(11): 3512-3518.
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