澜沧江某水电工程大型倾倒变形体边坡成因机制
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摘要
在现场调查资料的基础上,结合倾倒变形体边坡地形地貌特征、地层岩性特征、结构面发育特征、河谷地应力以及岩体力学性能的差异等方面对澜沧江某水电工程大型倾倒变形体边坡的成因机制进行了综合分析。结果表明:该大型倾倒变形体边坡地形上呈单薄、突出、三面临空的山梁;地层以薄层陡倾状岩体为主,并且在河谷下切过程中,砂岩和板岩将会出现差异卸荷回弹;边坡岩体中发育与倾倒变形体变形方向一致或相反的裂隙,有利于倾倒变形体的初始变形;河谷下切之前现今地面线附近岩体原始积累的地应力较高,当河谷下切至现今地面线时岩体卸荷强烈;在上述原因的共同作用下,倾倒变形体边坡向临空面发生大规模的倾倒变形。
Based on field investigation of a hydropower project on the Lancangjiang River,this study analyzed the formation mechanism for a large-scale toppling rock mass in terms of the topographical features,lithological characteristics, crack orientation,in situ stress of the slope,and different mechanic capabilities.The results indicate that: the rock slope of the right dam shoulder is isolated and protruding;the stratum thickness is less than 10 cm and the unloading rebound displacements between the sandstones and the slates are different during the valley cutting;the cracks with the same or contrary orientation as the distortion orientation of distortion rock mass are beneficial to initiatory distortion of the toppling rock mass;and the computational results of the finite element method(FEM) also suggest that the in situ stress is much higher underground before the valley cutting and the rock mass unloading is intensively released after the valley cutting.Due to the aforementioned reasons,a significant toppling of the side slope rock mass may occur.
Based on field investigation of a hydropower project on the Lancangjiang River,this study analyzed the formation mechanism for a large-scale toppling rock mass in terms of the topographical features,lithological characteristics, crack orientation,in situ stress of the slope,and different mechanic capabilities.The results indicate that: the rock slope of the right dam shoulder is isolated and protruding;the stratum thickness is less than 10 cm and the unloading rebound displacements between the sandstones and the slates are different during the valley cutting;the cracks with the same or contrary orientation as the distortion orientation of distortion rock mass are beneficial to initiatory distortion of the toppling rock mass;and the computational results of the finite element method(FEM) also suggest that the in situ stress is much higher underground before the valley cutting and the rock mass unloading is intensively released after the valley cutting.Due to the aforementioned reasons,a significant toppling of the side slope rock mass may occur.
引文
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[9]徐佩华,陈剑平,黄润秋,等.锦屏Ⅰ级水电站解放沟左岸边坡倾倒变形机制的3D数值模拟[J].煤田地质与勘探,2004(4):40-43.
[10]李德亮,石崇,聂卫平,等.基于土性相关蒙特卡罗法的争岗滑坡堆积体可靠性分析[J].河海大学学报:自然科学版,2011,39(3):317-322.
[2]姚爱军,苏伯苓.公伯峡坝前倾倒体地震敏感性数值模拟分析[J].河北地质学院学报,1995(2):150-154.
[3]邹正明.富溪连拱隧道出口变形倾倒体仰坡治理工程[J].合肥工业大学学报:自然科学版,2006,29(12):1556-1559.
[4]周克发,王昭升,张士辰,等.克孜尔水库主坝右坝肩倾倒体结构稳定安全评价[J].大坝与安全,2007(6):21-24.
[5]苟富民.麒麟寺水电站坝前左岸倾倒体稳定性分析研究[J].西北水电,2008(4):8-14.
[6]宋彦辉,黄民奇,陈新建.班多水电站左岸Ⅰ号倾倒体破坏机制分析[J].水利水电科技进展,2007,27(5):50-52.
[7]谢莉,李渝生,曹建军,等.澜沧江某水电站右坝肩岩体倾倒变形的数值模拟[J].中国地质,2009,36(4):907-914.
[8]张国新,赵妍,石根华,等.模拟岩石边坡倾倒破坏的数值流形法[J].岩土工程学报,2007,29(6):800-805.
[9]徐佩华,陈剑平,黄润秋,等.锦屏Ⅰ级水电站解放沟左岸边坡倾倒变形机制的3D数值模拟[J].煤田地质与勘探,2004(4):40-43.
[10]李德亮,石崇,聂卫平,等.基于土性相关蒙特卡罗法的争岗滑坡堆积体可靠性分析[J].河海大学学报:自然科学版,2011,39(3):317-322.
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