摘要
降雨型浅层滑坡是世界范围内最常见的地质灾害之一,坡度往往作为最重要的山坡地形特征被用于大量的滑坡易发性风险评估工作中。然而,坡顶至坡脚之间的复杂地形变化对降雨过程中的山坡水文响应过程有重要影响,但在以往的降雨型浅层滑坡研究中往往被忽视。运用一种耦合坡体稳定性模型和分布式山坡水文模型的数值模拟方法研究地形特征对降雨型浅层滑坡的影响,模拟102组不同坡度、坡型和曲率组合的山坡在降雨条件下的坡体稳定性时空演变规律。结果表明:(1)平均坡度增大总体上会增大坡体失稳的风险,在降雨过程中影响坡体安全系数骤降的时刻和位置;在降雨结束,孔隙水压力消散的过程中影响坡体安全系数回升的时刻和位置。(2)坡型控制着坡体失稳的位置分布,凹坡和凸坡的失稳往往分别发生在坡顶和坡脚;上凹下凸型(S1)山坡的失稳往往同时最先发生在坡顶和坡脚,并逐步向中部曼延;上凸下凹型(S2)山坡的失稳往往最先发生在坡中,并逐步向两侧蔓延;平坡往往容易在滑动面发生整体滑坡。(3)山坡曲率的大小一定程度上影响失稳区域、欠稳定区域、基本稳定区域和稳定区域在不同深度下的面积比例。(4)坡型和曲率主要通过控制山坡各点局部坡度的大小和变化规律来影响降雨型浅层滑坡的失稳位置、深度与时刻。通过数值模型试验阐明了在相同平均坡度的条件下坡型和曲率的差异也会导致边坡失稳状态的变化。因此在未来的降雨型浅层滑坡风险易发性评估和滑坡监测、预警及防治工作中需进一步考虑坡型、曲率等地形因素的影响。
Rainfall-induced shallow landslide is one of the most common geological hazards in the world.Slope angle is often used as the most important geomorphic characteristics in a large number of landslide susceptibility risk assessments.However,the complex terrain changes from the top to the toe of the hillslopes have important influences on the hillslope hydrological responses during rainfall,which were often ignored in the previous studies on rainfall-induced shallow landslides.A numerical simulation method coupling slope stability model and distributed hydrological model was applied to study the geomorphic impacts on rainfall-induced shallow landslides.The temporal and spatial changes of slope stability under 102 modelling scenarios with various combinations of slope angle,slope types and curvature were simulated and analyzed.Results showed that the increases of average slope generally enlarged the risk of slope instability,and affected the time and position shallow landslides,while the slope type controlled the spatial distributions of unstable area.The instability areas of concave slopes and convex slopes often occurred at the upper and lower areas of the slope,respectively.The instability areas of the up-concave and down-convex(S1)slope often initially occurred at the upper and lower parts of the slope simultaneously,and gradually extended to the middle part,while the situation of up-convex and down-concave(S2)slopes were just opposite.Besides,slope curvatures,to a certain extent mainly affected the area ratios of unstable region,less stable region,basically stable region and stable region at different depths.Moreover,those impacts of slope types and curvatures on rainfall-induced shallow landslides were mainly due to their controlling on the changes of local slopes at each point of the hillslope.It is illuminated that the differences of slope type and curvature will also lead to the changes of slope instability state under the same condition of average slope angle.Therefore,the influence of geomorphic characteristics such as slope type and curvature should be further considered in the future risk assessment,monitoring,early warning and prevention of rainfall-induced shallow landslides.
作者
赵鹏
邱平
何展昌
禹聪
赛志高
刘大鹏
王开正
唐鸿磊
ZHAO Peng;QIU Ping;HE Zhanchang;YU Cong;SAI Zhigao;LIU Dapeng;WANG Kaizheng;TANG Honglei(Zhaotong Bureau of Power Supply of Yunnan Power Grid Co.,Ltd.,Zhaotong 657000,Yunnan,China;Kunming University of Science and Technology,School of Electric Power Engineering,Kunming 650500,Yunnan,China)
出处
《水利水电技术(中英文)》
北大核心
2024年第S2期632-641,共10页
Water Resources and Hydropower Engineering
基金
云南电网有限责任公司2022年应用研究类科技项目(YNKJXM20220112)
国家自然科学基金项目(52107017)
中国水利水电科学研究院实验室开放基金(IWHR-SKL-KF202220)
云南省基础研究计划青年项目(KKSQ202204032)
云南省“兴滇英才支持计划”青年人才项目(KKRD202204022)
关键词
降雨型浅层滑坡
地形特征
坡型
山坡曲率
分布式水文模型
rainfall-induced shallow landslide
geomorphic characteristics
slope type
slope curvature
distributed hydrological model
