基于降雨诱发的地质灾害链动态演进与风险传递机制研究——以湖北省恩施市沐抚镇余家沟为例

Study on Dynamic Evolution and Risk Transmission Mechanism of Geological Hazards Chain Induced by Rainfall——Taking Yujiagou in Mufu Town in Enshi City in Hubei Province as an Example

摘要:

针对降雨诱发地质灾害链的级联效应与风险传递机制，本研究以湖北省恩施市沐抚镇余家沟为典型研究区，基于资料收集分析与地面调查，识别出9处滑坡体作为灾害链的初始物源。通过极限平衡法采用FLAC3D模型，量化不同降雨强度下滑坡稳定性系数（Fs），揭示滑坡失稳触发泥石流的传递机制。进一步采用RAMMS软件模拟泥石流运动轨迹与堆积特征，结合沟谷地形与物质通量分析，构建滑坡—泥石流—堰塞湖三级链生灾害的风险传递模型。通过地质灾害链风险分析实践，基本模拟了地质灾害链的致灾过程，可为西南山区地质灾害链的早期预警与风险管理提供科学依据。

Abstract:

In response to cascading effects and risk transmission mechanism of rainfall induced geological hazards, taking Yujiagou in Mufu town in Enshi city in Hubei province as a typical research area, based on data collection, analysis and ground investigation, 9 landslide bodies have been identified as the initial sources of hazard chain. By using the limit equilibrium method and FLAC 3D model, the stability coefficient (Fs) of landslides under different rainfall intensities has been quantified. Transmission mechanism of landslide instability triggering debris flows has been revealled. By using RAMMS software, the trajectory and accumulation characteristics of debris flows have been simulated. Combining with analysis of valley terrain and material flux, a risk transfer model for three level chain of landslide debris flow barrier lake disasters has been constructed. Through practice of geological hazard chain risk analysis, the disaster process of geological hazard chain has been basically simulated. It can provide scientific basis for early warning and risk management of geological hazard chain in southwestern mountainous areas.