GS水电站泄洪出口边坡工程地质特征及稳定性评价  

Engineering Geological Characteristics and Stability Evaluation of Slope at Discharge Outlet of GS Hydropower Station

作　　者：罗军尧 朱国金 冯业林 陈光明 黄青富 程伟 王玉杰[2] 杨旸 杨太强 LUO Junyao;ZHU Guojin;FENG Yelin;CHEN Guangming;HUANG Qingfu;CHENG Wei;WANG Yujie;YANG Yang;YANG Taiqiang(Power China Kunming Engineering Corporation Limited,Kunming 650051,China;China Institute of Water Resources and Hydropower Research,Beijing 100089,China)

机构地区：[1]中国电建集团昆明勘测设计研究院有限公司,昆明650051 [2]中国水利水电科学研究院,北京100089

出　　处：《材料导报》2023年第S02期275-281,共7页Materials Reports

基　　金：国家重点研发计划(2018YFC1508500);华能集团科技项目(HNKJ22-H107)。

摘　　要：岩体倾倒变形失稳是我国西部大型水电工程建设面临的主要地质灾害问题之一。以古水水电站泄洪出口边坡为例,综合采用野外精细调查、平硐勘查、理论分析以及数值模拟相结合的方法对研究区工程地质特征及边坡稳定性等问题进行了深入研究。结果表明,研究区地形陡峭,受澜沧江及支流木水河的双向下切作用影响,呈现出典型的双向临空地形地貌特征;受大型地质构造作用影响,出露岩体多呈碎裂、碎块状,破碎程度极高,风化及卸荷发育深度较大,并且还发育有多级结构面。研究区内岩体的倾倒变形最初是由澜沧江下切导致岩体卸荷拉裂及变形过程中的倾倒拉裂引起的,随后续木水河的下切及坡体变形的进一步加剧,浅层倾倒变形逐步向深层扩展,最终导致区内岩体演变为双向倾倒折断。稳定性分析结果表明,未开挖时,边坡处于基本稳定状态,但在开挖过程中,受开挖应力调整的影响,边坡可能会出现岩体倾倒变形的进一步的加剧甚至发生失稳破坏。根据边坡开挖加固方案,采用离散元模拟,论证了预应力锚索+抗剪洞支护方案的可行性。Toppling deformation and instability of rock mass is one of the main geological hazards in the construction of large⁃scale water conservancy and hydropower projects in western China.Taking the Gushui hydropower station as an example,this paper makes an in⁃depth study of the engineering geological characteristics and stability evaluation of the study area by combining field investigation,tunnel investigation,and theoretical analysis.The results show that the topography of the study area is steep.Under the influence of bidirectional downward cutting of Lancang River and its tributary Mu Shui River,the study area presents typical bidirectional open air topographic and geomorphic features.Influenced by large⁃scale geological tectonics,the exposed rock mass is mostly in the form of fragmentation and fragmentation,with a high degree of fragmentation,and a large depth of weathering and unloading development,and multi⁃level structural plane is also developed.With the downcutting of Mushui River and the further intensification of slope deformation,the shallow toppling deformation gradually expanded to the deep layer,and some rock masses were tilted to the side of Mushui River,resulting in the rock mass evolving into bidirectional toppling fracture.The stability analysis results show that the slope is basically stable when it is not excavated,but during the excavation process,the slope is affected by the adjustment of excavation stress,which may cause the further aggravation of the toppling deformation of the slope rock mass and even the destabilization failure.According to the slope excavation and reinforcement scheme,the feasibility of prestressed anchor cable+shear hole support scheme is demonstrated by using discrete element simulation.

关 键 词：GS水电站 倾倒变形 双向卸荷 工程地质特征 稳定性分析 

分 类 号：TU42[建筑科学—岩土工程]