弯道特征对泥石流堵塞系数的影响研究

The coefficient of amplification is an important parameter to predict the discharge of debris flow. It depends on many characteristic indexes, one of which is the meandering channel. Without an established method for determining its values, the accuracy of calculation results of debris-flow discharge is affected. In order to make a reasonable design of debris flow control measurements, the prerequisite is to establish a division standard of debris flow amplification coefficient by these characteristic indexes. Focused on the influence of meandering channels, taking Longmen Fault Zone in the upper reaches of Minjiang River (From Dujiangyan to Wenchuan) as a study area, by the way of field exploration and model experiment indoor, this research is to study scouring and silting characteristics of debris flow under different meandering conditions, and analyze the correlation between meandering characteristics and debris-flow discharge. Also, this research is aimed to reveal the critical value of meandering channel which cause a blockage in the movement of debris flow, and establish a physical model or semi empirical mathematical expressions to determine the coefficient of amplification affected by meandering channel, which provides a theoretical reference for the engineering design of debris flow control.

堵塞系数是泥石流治理勘查设计中计算流量的重要参数，目前主要根据流体性质、地形特征和物源条件等因素进行综合考虑取值。弯道是天然泥石流沟的重要特征之一，对泥石流的冲淤特征、堵溃效应和流量演进等运动特征具有一定影响作用，是确定弯道段泥石流堵塞系数的重要判别指标，但缺乏具体的划分方法，影响泥石流流量计算结果的准确性。为了科学和准确地预测泥石流流量，本研究从弯道特征对泥石流堵塞系数影响的研究出发，以龙门山断裂带岷江上游（都江堰至汶川段）为研究区域，通过对典型弯道泥石流沟的野外勘查和室内弯道水槽模型实验，研究不同弯道条件下泥石流的冲淤特征和堵溃效应的成因机制，分析弯道特征与泥石流流量演进规律的关系，揭示泥石流发生堵溃效应的临界弯道特征，探讨基于弯道特征而确定堵塞系数的物理模式或经验公式，为泥石流防治工程设计提供一定理论参考。

堵塞系数是泥石流治理勘查设计中计算流量的重要参数，目前主要根据流体性质、地形特征和物源条件等因素进行综合考虑取值。弯道是天然泥石流沟的重要特征之一，对泥石流的冲淤特征、堵溃效应和流量演进等运动特征具有一定影响作用，是确定弯道段泥石流堵塞系数的重要判别指标，但缺乏具体的划分方法，影响泥石流流量计算结果的准确性。为了科学和准确地预测泥石流流量，本项目从弯道特征对泥石流堵塞系数影响角度出发，以汶川地震灾区为研究区域，通过8处典型弯道泥石流沟的野外勘查和29组室内弯道水槽模型实验，揭示了不同弯道条件下泥石流的冲淤特征和堵溃效应的成因机制，初步建立了弯道特征与泥石流流量演进规律的关系模型，建立了泥石流发生堵溃效应的临界弯道特征判别方法，建立了基于弯道特征而确定堵塞系数的物理模式或经验公式，为泥石流防治工程设计提供了一定理论参考。