藏东南地区冰碛土强度特性对温度响应试验研究  

Experimental Study on Response of Strength Characteristics of Glacier Tills to Temperature in Southeast Tibet

作　　者：刘振兴 王姣 崔鹏 江耀[2,3] 王睿 刘子明 Liu Zhenxing;Wang Jiao;Cui Peng;Jiang Yao;Wang Rui;Liu Ziming(Key Laboratory of Land Surface Pattern and Simulation,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;Key Laboratory of Mountain Hazards and Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences&Ministry of Water Conservancy,Chengdu 610041,China;China-Pakistan Joint Research Center on Earth Sciences,CAS-HEC(Chinese Academy of Sciences-Higher Education Commission of Pakistan),Islamabad 45320,Pakistan;University of Chinese Academy of Sciences,Beijing 100049,China;Faculty of Engineering,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国科学院地理科学与资源研究所陆地表层格局与模拟中科院重点实验室,北京100101 [2]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重点实验室,四川成都610041 [3]中国‒巴基斯坦地球科学研究中心,中国科学院‒巴基斯坦高等教育委员会,巴基斯坦伊斯兰堡453204 [4]中国科学院大学,北京100049 [5]中国地质大学工程学院,湖北武汉430074

出　　处：《地球科学》2025年第1期322-335,共14页Earth Science

基　　金：第二次青藏高原科学考察研究(No.2019QZKK0906);国家自然科学基金委员会区域创新发展联合基金(No.U20A20112);国家自然科学基金青年科学基金项目(No.42101088)。

摘　　要：为研究气候暖湿化条件下小冰期以来所形成的冰碛土内埋藏冰消融导致强度劣化机理,深入认识高寒区冰川泥石流起动过程,选取帕隆藏布流域天魔沟泥石流源区所采集的冰碛土作为研究对象;采用高精度温控三轴耦合试验系统进行剪切试验,研究冰碛土在不同温度条件下的剪切变形特征,分析温度对冰碛土变形破坏的影响机制,构建冰碛土多相介质强度破坏判据.试验结果表明,冰碛土变形破坏受温度影响显著,-20℃时,冰碛土应变软化和剪切带破坏特征显著;随着温度升高,冰碛土逐渐表现出应变硬化和鼓胀破坏特征.冰碛土的模量、峰值抗剪强度、内摩擦角和黏聚力均随温度升高而降低,且在-3~-5℃下降速率最快,而脆性指数随温度升高而增大.引入Boltzmann函数对冰碛土抗剪强度参数与温度间的关系进行刻画,发现抗剪强度参数变化的特征温度在-4℃附近,并基于摩尔库伦强度准则构建了含有温度参数的冰碛土强度破坏准则.与传统含有构造冰的冻土相比,内部赋存埋藏冰的冰碛土强度主要由颗粒间接触提供,其更易受外界温度变化影响,土体强度对温度响应更为复杂.The mechanism of soil strength deterioration caused by the melting of buried ice in glacier tills formed since the Little Ice Age under the climate warming and humidification is of great significance for deeply comprehending the initiation process of glacier debris flow.Taking the soil from the source of Tianmo gully debris flow in Parlung Tsangpo Basin as the research object,the high-precision temperature control triaxial coupling experimental system was used to study the shear deformation characteristics of glacier tills under different temperature conditions,analyze the influence mechanism of temperature on deformation and failure,and construct the strength failure criterion of this multiphase medium.The results show that the deformation and failure of glacier tills were significantly affected by temperature.At-20℃,the glacier tills showed strain softening and shear band failure characteristics,and the glacier tills gradually exhibited strain hardening and bulging failure characteristics with the increasing temperature.The modulus,peak shear strength,internal friction angle and cohesion decreased with the increase of temperature,and the rate was fastest at-3 to-5℃,while the brittleness index increased with temperature increasing.Boltzmann function was introduced to describe the relationship between shear strength parameters and temperature.Analyses show that the critical temperature of shear strength parameter variation was around-4℃.The strength failure criterion of glacier tills containing temperature parameters was constructed based on Mohr-Coulomb theory.Compared with frozen soil containing pore ice,the strength of glacier tills which contain buried ice is mainly provided by the contact between particles,which is easier to be affected by the change of external temperature,and the response of strength to temperature is more complex.

关 键 词：冰碛土 强度劣化 温度作用 温控三轴试验 工程地质学 

分 类 号：P642.23[天文地球—工程地质学]