弱胶结宽级配卵漂石工程地质特性及边坡稳定性研究  

Study on engineering geological characteristics and slope stability of weakly cemented widely graded pebble and boulders

作　　者：雷世兵 黄振伟 蒲进 张涛 孙韬 熊宇康 LEI Shibing;HUANG Zhenwei;PU Jin;ZHANG Tao;SUN Tao;XIONG Yukang(Changjiang Geotechnical Engineering Co.,Ltd.,Wuhan 430010,China;Changjiang Survey,Planning,Design and Research Co.,Ltd.,Wuhan 430010,China;Xizang Datang Zhala Hydropower Development Co.,Ltd.,Changdu 854000,China)

机构地区：[1]长江岩土工程有限公司,湖北武汉430010 [2]长江勘测规划设计研究有限责任公司,湖北武汉430010 [3]西藏大唐扎拉水电开发有限公司,西藏昌都854000

出　　处：《水利水电快报》2024年第6期27-32,42,共7页Express Water Resources & Hydropower Information

基　　金：中国大唐集团有限公司科研项目“西藏扎拉水电站工程区弱胶结卵漂石混合土工程特性及边坡稳定性研究”(CWEME-2404XZ-F002)。

摘　　要：青藏高原山区河流阶地发育,区域内卵漂石具有弱胶结、宽级配、超大粒径颗粒含量较多等特点,工程地质特性及边坡稳定性研究难度大。采用现场原位试验、室内试验和地质调查测绘等方法,初步查明西藏扎拉水电站工程区卵漂石颗粒级配及抗剪强度。通过近景测量摄影、图像处理技术与常规颗粒分析试验相结合可确定颗粒级配,基于实测边坡地形和调查稳定坡角,结合稳定性反演计算可获得抗剪强度参数。结果表明:天然和饱水条件下卵漂石的内摩擦角差别不大,但饱水条件黏聚力仅为天然条件的25%~40%,由此对正常蓄水位以下、以上的库坝区边坡分别采取不同的支护措施,确保了处理方案的安全性与经济性。研究结果可为库坝区卵漂石边坡稳定性计算评价及处理方案设计提供地质依据。Rivers and terraces are developed in the Qinghai-Xizang Plateau areas.The boulders in this area have the characteristics of weak cementation,wide gradation,and high content of super-large particles,so it is difficult to study their engineering geological characteristics and slope stability.By field test,indoor test and geological investigation,the grain composition and shear strength of boulder and cobble in Xizang Zhala Hydropower Station were investigated,and the grain composition of boulder and cobble can be accurately determined by combining close-range measurement photography,image processing technology with conventional grain analysis test.The shear strength parameters of boulders can be accurately obtained based on the measured slope topography and the investigated stable slope angle combined with the stability inversion calculation.The results showed that under natural and saturated conditions,the internal friction angle of boulder pebble had little difference,but the cohesion of boulder pebble under saturated condition was only 25%~40% of that under natural condition.Therefore,different supporting measures were taken for the slopes below and above the normal water level to ensure the safety and economy of the treatment scheme.The research results can provide a geological basis for the calculation and evaluation of the weakly-cemented wide-graded boulder slope stability in the reservoir and dam area and the design of the treatment scheme.

关 键 词：弱胶结 宽级配 卵漂石 地质特性 边坡稳定性 扎拉水电站 

分 类 号：O319.56[理学—一般力学与力学基础]