兰州市地质灾害发育分布特征与典型滑坡群致灾机制

    Development and distribution characteristics of geological hazards and disaster-causing mechanism of typical landslide groups in Lanzhou

    • 摘要: 兰州市地质环境复杂,地质灾害频发,防灾形势严峻。基于甘肃省1∶50000地质灾害风险调查,系统分析总结了兰州市地质灾害发育特征与分布规律;采用合成孔径雷达干涉测量(InSAR)技术,阐明了徐家湾滑坡群的时空演化特征,并结合现场地质调查,揭示了徐家湾滑坡群破坏模式与致灾机制。研究表明:①兰州市地质灾害以潜在不稳定斜坡、泥石流和滑坡为主导,合计占灾害总数的86.0%;②兰州市主城区灾害点主要分布于黄河及其支流两岸、地质构造密集发育部位及工程扰动强烈地区,尤其在黄河两岸高阶地前缘的市民居住区、工业密集区;③徐家湾滑坡群最大年形变速率为15.85 mm/a,其发育受新构造运动与岩体结构控制,地震和集中降雨进一步降低岩土体强度,人类工程活动是触发灾变的关键因素;④针对兰州市地质灾害特点,提出了构建“空-天-地”一体化监测预警体系、加强工程活动全周期管控、推行“分区-分类-分级”差异化防治策略、深化灾害链生效应研究、提升公众防灾意识等综合防灾减灾对策。研究成果可为黄河上游地区的地质灾害风险防控、国土空间安全规划与高质量发展提供科学支撑。

       

      Abstract: Lanzhou City is characterized by a complex geological environment and frequent geohazards, posing severe challenges to disaster prevention and mitigation. Based on the 1∶50000 geological hazard risk survey of Gansu province, this study systematically analyzes and summarizes the development characteristics and distribution patterns of geological hazards in the area. Using Interferometric Synthetic Aperture Radar (InSAR) technology, the spatiotemporal evolution of the Xujiawan landslide group is clarified, and combined with field geological surveys, its failure modes and disaster-causing mechanisms are revealed. The results indicate that: (1) Geological hazards in Lanzhou are dominated by potentially unstable slopes, debris flows, and landslides, collectively accounting for 86.0% of the total hazards; (2) Hazard sites in the main urban area are primarily distributed along both banks of the Yellow River and its tributaries, in zones with intensive geological structures, and in areas subject to strong engineering disturbance, especially in residential and industrial zones located at the front edges of high terraces along the Yellow River; (3) The Xujiawan landslide group exhibits a maximum annual deformation rate of 15.85 mm/year. Its development is controlled by intense neotectonic activity, with jointed and fractured rock masses providing a structural basis for slip surface formation. High-intensity earthquakes and concentrated rainfall further reduce the shear strength of the rock and soil mass; (4) Human engineering activities are key triggering factors for landslide disasters. Large-scale excavation at slope toes creates steep free surfaces, directly disrupting the original stress equilibrium, whereas irrigation and urban construction loading significantly increase pore water pressure and slope load. The research results of this study provide empirical evidence and scientific support for geohazard risk prevention and sustainable development in Lanzhou City.

       

    /

    返回文章
    返回