藏东南帕隆藏布流域冰碛物典型特征及工程效应  

Characteristics of Typical Glacial Tills in Parlung Zangbo Basin in Southeastern Tibet and Its Engineering Effect

作　　者：杨东旭[1,2,3] 游勇 王军朝[2] 杨栋 刘建康 YANG Dongxu;YOU Yong;WANG Junchao;YANG Dong;LIU Jiankang(Institute of Mountain Hazards and Environment,CAS&Ministry of Water Conservancy,Chengdu 610041,China;Institute of Exploration Technology,Chinese Academy of Geological Sciences,Chengdu 611734,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院、水利部成都山地灾害与环境研究所,山地灾害与地表过程重点实验室,四川成都610041 [2]中国地质科学院探矿工艺研究所,中国地质调查局地质灾害防治技术中心,四川成都611734 [3]中国科学院大学,北京100049

出　　处：《防灾减灾工程学报》2020年第6期841-851,共11页Journal of Disaster Prevention and Mitigation Engineering

基　　金：第二次青藏高原综合科学考察研究(2019QZKK0902);国家自然科学基金青年基金项目(41807300);中国地质调查局二级项目(DD20160279,DD20190644)资助。

摘　　要：为详细调查拟建川藏铁路沿线帕隆藏布流域冰碛物的物理力学特征,评估冰碛物作为地质灾害物源和工程地基的稳定性,选取帕隆藏布流域32处典型冰碛物为研究对象,通过开展天然密度、含水率、颗分、大型直剪、三轴剪切、膨胀性、渗透性等原位试验和室内测试,结合现场剖面测绘等调查手段,总结了冰碛物的分布与沉积特征和物理力学参数特征,统计了不同参数间的相关性。结果表明:冰碛物物理力学参数与含水率、孔隙比及粘粒含量密切相关,其中天然密度和压缩模量均与孔隙比呈线性负相关,而垂直渗透系数和自由膨胀率与粘粒含量呈二次方关系,抗剪及抗压强度与孔隙比和含水率呈二元函数关系。通过分析冰碛物在三种不同沉积部位(现代冰舌前缘、冰川谷中游、沟口主河岸坡)的起动方式,初步探讨了冰碛体的稳定性及其在川藏铁路、川藏高速公路等重大工程中的不同应用对策(桥隧绕避、工程边坡、路堑或地基等)。The southeast region of Tibet is the largest marine glacier area in China.For investigating the physical and mechanical characteristics of glacial tills along the Sichuan-Tibet railway,and evaluating their stability as a geological hazard source and engineering foundation,32 points of glacial tills in the Parlung Zangbo basin were taken as cases.A series of in-site and indoor tests on natural density,grain size analysis,large direct shear,triaxial shear,compressive strength,permeability coefficient and so on were carried out.Combining with field investigation methods such as sectional surveying and mapping,the distribution,morphological characteristics,physical and mechanical properties of glacial till and their correlation were analyzed.The result shows that physical and mechanical properties are closely related to moisture content,void ratio and clay content.The natural density and com‑pression modulus are negatively linear related to the void ratio.The vertical permeability coefficient and the free expansion ratio show a quadratic relationship with clay content.The shear strength and compressive strength are binary relationship with void ratio and moisture content.Start-up patterns in three different deposit sites(modern glacier tongue,middle reaches of the valley,and the main river bank)were summarized,and the stability of the glacial tills was preliminarily discussed.The countermeasures for dealing with the glacial tills in Sichuan-Tibet railway and highway projects were suggested,such as passing by bridges or tunnels,engineering slope,and cutting or foundation,etc.

关 键 词：藏东南 海洋性冰川 冰碛物 物理力学特征 地质灾害 

分 类 号：P642.3[天文地球—工程地质学]