澜沧江某水电工程大型倾倒变形体边坡成因机制  

Integrated analysis of formation mechanism for large-scale toppling rock mass of a hydropower station on Lancangjiang River

作　　者：周洪福[1] 聂德新[2] 李树武[3] 

机构地区：[1]中国地质调查局成都地质调查中心,四川成都610081 [2]成都理工大学环境与土木工程学院,四川成都610059 [3]中国水电顾问集团西北勘测设计研究院,陕西西安710065

出　　处：《水利水电科技进展》2012年第3期48-52,共5页Advances in Science and Technology of Water Resources

基　　金：国家自然科学基金(40372127)

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.

关 键 词：大型边坡 倾倒变形体 成因机制 数值分析 澜沧江 

分 类 号：TV223[水利工程—水工结构工程]