ISSN 1003-8035 CN 11-2852/P

    花岗岩地区群发性降雨滑坡孕灾条件敏感性研究以桂东南北流市为例

    Study on the sensitivity of disaster-breeding conditions for rainfall-induced cluster landslides in granite areas: Case study of Beiliu City in southeast Guangxi

    • 摘要: 近年来,极端强降雨在我国南方全强风化花岗岩地区诱发了多起群发性滑坡事件,造成了严重的损失。由于区域性的极端气候、厚层风化花岗岩与不规范切坡等因素,群发滑坡频频发生。但滑坡发育特征及孕灾条件尚不明确,给地质灾害监测和防治带来挑战。文章以广西北流市花岗岩地区为研究区,采用现场调查、遥感解译与XG-boost模型,探讨了降雨型群发滑坡的发育特征、时空分布规律、破坏模式和孕灾条件敏感性。结果表明,区内两起暴雨事件共引发滑坡1670处,以中小规模为主,占总数量的72.57%。群发滑坡集中发育于高程<300 m、坡度>75°的切坡地形下,表现出分布范围广、规模小、数量多、即雨即滑、爆发性强的特点,主要形成剪切滑移型、滑塌型及流滑型(碎屑流)三类破坏模式。距居民点距离(概率贡献为22.22%)、坡度(15.25%)、高程(14.47%)及植被覆盖度(12.01%)是诱发花岗岩地区降雨型群发滑坡的主要孕灾条件。本研究可为花岗岩地区降雨型群发滑坡的研究提供依据,在防控减灾方面具有重要意义。

       

      Abstract: In recent years, extreme heavy rainfall has triggered numerous cluster landslide events in the fully weathered granite areas of southern China, causing severe losses. Factors such as regional extreme weather, thick weathered granite layers, and non-standard slope cutting practices have led to frequent occurences of cluster landslides. However, the developmental characteristics and conditions conductive to these landslides are not well-understood, posing challenges to geological disaster monitoring and prevention. This paper focuses on the granite area of Beiliu City in Guangxi as the study area. The study discuss the developmental characteristics, spatiotemporal distribution patterns, failure modes, and sensitivity of disaster-breeding conditions of rainfall-induced cluster landslides through an integrated approach combining field investigations, remote sensing interpretation, and XG-boost modeling. The results show that two rainstorm events in the area triggered 1,670 landslides, mainly of small to medium scale, accounting for 72.57% of the total occurrences. The cluster landslides primarily developed in cut slopes with elevations less than 300 meters and slope angles greater than 75°, exhibiting characteristics of wide spatial distribution, small individual scale, high frequency, immediate response to rainfall, and strong explosiveness. Three main types of failure modes were identified: shear-sliding, toppling-sliding, and flow-sliding (debris flow). The primary disaster-breeding conditions were identified as distance to residential areas (proportion contribution of 22.22%), slope (15.25%), elevation (14.47%), and normalized difference vegetation index (12.01%) in the granite areas. This study provides a basis for the research of rainfall-induced cluster landslides in granite areas and is of great significance in disaster prevention and mitigation.

       

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