基于历史观测数据的泥石流突变起动模式研究——以陇南山区白龙江流域为例

泥石流的起动过程是泥石流发展成灾的首要和关键环节。以陇南山区白龙江流域多场泥石流原型观测历史数据为依托,基于突变理论,首次将液固比S_r、沟床坡度α和细粒含量C作为泥石流起动的控制参量,建立了细粒含量与泥石流起动之间的量化关系。研究结果表明:坡度一定时,细粒含量对泥石流的起动模式起到决定性作用。就陇南山区白龙江流域而言:小于1 mm细颗粒含量15%以下时,泥石流常以突然起动模式为主,细颗粒含量15%～30%之间时,多以渐变模式起动,而细颗粒含量30%以上时,逐渐表现为缓慢起动的特点。可通过改变其主要的运动控制参量,一定程度上预防并控制其发生发展方向。研究结果对进一步拓展突变理论应用范围、丰富泥石流起动非线性理论体系及野外泥石流预测预报与防治等具有重要的科学意义和实践指导价值。

Historical Field Observation Data-based Study on the Catastrophic Initiation Mode of Debris Flows:A Case of the Bailong River Basin in Longnan Mountain Areas

The starting process of debris flow is the first and important link in the development of debris flow.Based on the catastrophe theory,the liquid-solid ratio Sr,slope of gully bed and fine grain content C are taken as the control parameters for debris flow initiation for the first time,and the quantitative relationship between fine grain content and debris flow initiation is established.The results show that the fine grain content plays a decisive role in debris flow starting mode when the slope is constant.For Bailongjiang River Basin in Longnan Mountainous Area,when the content of fine particles is less than 15%,the debris flow usually starts abruptly.When the content of fine particles is between 15%and 30%,the debris flow starts gradually in a gradual mode.When the content of fine particles is more than 30%,the debris flow starts slowly.To some extent,its occurrence and development direction can be prevented and controlled by changing its main motion control parameters.The research results have important scientific significance and practical guiding value for further expanding the application scope of catastrophe theory,enriching the non-linear theory system of debris flow starting and predicting and preventing debris flow in the field.