基于试验模拟的滑坡泥石流灾害链风险监测预警

Monitoring and Early Warning of Landslide and Debris Flow Disaster Chain Risk Based on Experimental Simulation

[目的]开展以元阳梯田滑坡泥石流地质灾害链为基础的风险监测预警研究,为改善降雨诱发型滑坡泥石流灾害链的预警精度,提高防灾减灾工作针对性提供科学依据。[方法]采用降雨模型模拟试验来探讨元阳梯田滑坡—泥石流灾害链破坏过程,通过对降雨量、体积含水率和坡体变形破坏过程进行实时监测,分析不同降雨条件下灾害链风险预警阈值。试验设置长时间中雨(50 mm/h)、长时间暴雨(120 mm/h)、循环间歇暴雨和干旱突发型暴雨4种降雨工况。[结果]在降雨持续作用下,灾害链发展过程为:地表冲刷、蠕滑、快速滑动、泥石流运移及运移结束。坡体破坏最先从左侧坡脚开始,右侧坡脚稍后。不同降雨工况下坡体破坏形式不同:暴雨工况下坡体中部会产生一条横向裂缝,而形成上下两个滑块;中雨工况下坡体则陆续形成多个滑块;干旱突发暴雨工况下泥石流形成时间最短,运移距离最远,流通和堆积范围相比其他降雨工况更广。[结论]滑坡泥石流灾害链预警监测指标主要为累积降雨量、降雨持续时间、含水率变化和坡体变形发展现场监测。这些监测参数受降雨条件、土体性质、坡角和外部动力条件等诸多因素影响,因此在实际应用中需要综合考虑这些因素。

[Objective]Risk monitoring and early warning were studied based on the geological disaster chain of landslides and debris flows in Yuanyang terraced fields in order to improve the accuracy of warnings related to rainfall-induced landslides and debris flow disaster chains and to provide a scientific basis for improving the pertinence of work related to reducing and preventing such disasters.[Methods]This investigation delved into the failure process of disaster chains related to landslides and debris flows in the Yuanyang terraced area through rainfall model simulation experiments.Real-time monitoring of rainfall,volumetric moisture content,and slope deformation coupled with an analysis of the early-warning thresholds for disaster chain risks under various rainfall conditions formed a crucial part of the study.Four specific rainfall conditions〔i.e.,long-term moderate rain(50 mm/h),long-term heavy rain(120 mm/h),cyclic intermittent heavy rain,and drought-sudden heavy rain〕were established.[Results]The continuous impact of rainfall revealed the development stages of the disaster chain,progressing through surface scouring,creeping,rapid sliding,and debris flow migration until the culmination of the movement process.Slope damage initiated from the foot of the left slope,subsequently affecting the foot of the right slope.Various forms of slope damage manifested themselves under distinct rainfall conditions:transverse cracks appeared in the middle of the slope during heavy rain,resulting in the formation of two landslides(one above and one below);multiple landslides occurred consecutively under moderate rain conditions;and mudslides formed rapidly under drought-sudden heavy rain,covering the longest distances and accumulating over a broader area than observed for other rainfall scenarios.[Conclusion]The main monitoring indicators for disaster chain early warning of landslide and debris flow include cumulative rainfall,duration of rainfall,changes in moisture content,and on-site monitoring of slope deformation development.These monitoring parameters are influenced by various factors such as rainfall conditions,soil properties,slope angle,and external dynamic conditions.Therefore,in practical applications,it is necessary to comprehensively consider these factors.