气候变化环境下青藏高原含冰冰碛土斜坡水热力耦合特性与长期稳定性  

Coupling characteristics and stability evolution of ice-rich moraine soil slopes on the Tibetan Plateau under climate change

作　　者：李奇龙 周佳庆[2] 李长冬[1] 刘洪斌 王雪萦 吕豪 LI Qilong;ZHOU Jiaqing;LI Changdong;LIU Hongbin;WANG Xueying;LYU Hao(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China;State Key Laboratory of Water Resources Engineering and Management,Wuhan University,Wuhan 430072,China)

机构地区：[1]中国地质大学(武汉)工程学院,武汉430074 [2]武汉大学水资源工程与调度全国重点实验室,武汉430072

出　　处：《地质科技通报》2025年第1期112-125,共14页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42277177);国家重大自然科学基金川藏铁路重大基础科学问题专项(41941017)。

摘　　要：全球气候变暖形势严峻,温度的升高将直接导致广泛分布于青藏高原的各类含冰堆积体与冻结堆积体出现冻结区退化、热融沉降、失稳破坏等一系列工程地质问题。随着青藏地区人类生产实践与工程活动的日益频繁,这些工程地质问题将严重威胁着该地区的人民生命财产安全和重大工程建设进程。本研究建立了考虑冰水相变作用的岩土体渗流-传热-变形耦合数值模型,并通过与已有试验研究以及数值模拟研究的结果进行对比,充分验证了所搭建耦合模拟方法的有效性。基于所搭建的耦合模拟方法,聚焦帕隆藏布流域广泛分布的含冰冰碛土斜坡,结合历史气象数据和气候预测数据(SSP1-2.6与SSP5-8.5两种情景下),开展了自2020-2100年,时长80 a的斜坡多场耦合模拟与长期稳定性计算研究。结果表明,坡体内部各深度土体在长期变暖进程中均呈现不同程度的升温,并进一步导致坡体内部冻结区出现不可逆转的退化,从而导致相应的不可逆转的热融沉降与稳定性下降现象。冻结区的退化与其相应导致的不良工程地质现象受未来不同气候演化模式影响巨大。在SSP5-8.5情景下,持续升温至2080年前后,年均大气温度共抬升了3.84℃,坡体内部开始出现冻结区不可逆的退化与随之出现的不可逆沉降现象。在2080年坡体表层出现冻结区永久退化之后,坡体的热融沉降进程与稳定性的下降过程开始出现显著的加速现象,直至2100年,坡体热融沉降可达0.06 m,坡体稳定性较2020年下降了6.3%,这一非线性演化特征深刻反映了含冰土体这一特殊岩土材料在温度升高作用下由量变向质变转变的演化过程。而在SSP1-2.6情景下,冰碛土斜坡并未出现显著的冻结区退化与稳定性劣化的现象。本文构建的嵌入气候模型、考虑了冰水相变的岩土体温度-渗流-应力多场耦合模拟平台,量化评估了不同未来气候情�[Objective]The climate warming is severe on a global scale,and the increase in temperature directly leads to a series of engineering geological problems,such as the degradation of frozen regions,thermal thawing-induced subsidence,and the failure of various types of ice-rich and frozen geological structures widely distributed in the Qinghai–Tibetan Plateau.With the increasing frequency of human production practices and engineering construction in the Qinghai–Tibet region,these problems seriously threaten the safety of people's lives and property as well as the construction process of major projects in the region.[Methods]A coupled numerical model of seepage,heat transfer,and deformation considering the water–ice phase transition was established in this study,and its efficiency and accuracy were validated by comparisons with previous experimental and simulated studies.Focusing on the widely distributed moraine slopes containing ice in the Parlung Tsangpo Basin,combined with.historical meteorological data and climate prediction data(under the scenarios of SSP1-2.6 and SSP5-8.5),the multi field simulation and long-term stability calculation of slopes were carried out for 80 years from 2020 to 2100.[Results]The results revealed that the soil at different depths inside the slope body was warmed to different degrees under the effect of long-term warming process,which further leads to irreversible degradation of the frozen area inside the slope,resulting in irreversible melt-induced settlement and stability degradation.The degradation of frozen area and accompanying unfavorable geological problems are strongly affected by climate evolution patterns.As the temperature continues to rise until around 2080,the mean annual atmospheric temperature increased by 3.84℃under SSP5-8.5,and irreversible degradation of the frozen zone and the consequent irreversible subsidence began to occur inside the slope.After the permanent degradation of the frozen zone in the surface layer of the slope in 2080,there was a significant acc

关 键 词：气候变化 青藏高原 含冰冰碛土 水热力耦合 斜坡稳定性 

分 类 号：P642.22[天文地球—工程地质学]