国内外泥石流活动关键指标估算方法之比较

泥石流流体容重、流速、冲击力是表征泥石流活动特征众多指标中的三个关键指标.本文在分析国内外对这些指标评估现状的基础上,总结了应用较普遍的估算公式,对比了不同公式的特点及其适用性.比较结果认为:由于泥石流组成和运动状态的复杂性以及影响因素的多样性,对于这三个指标,目前的估算公式都不具有普适性.在当前的认知水平下,建立基于各个地区泥石流特点的指标估算经验公式是最为实用的途径.在各个指标经验公式的建立方法上,考虑各个粒组的多变量容重统计分析方法相对较为合理；泥石流流速估算公式的建立途径在我国、前苏联和欧美国家之间有显著差异,前二者基于曼宁公式,后者基于强迫涡流公式、以弯道超高为主要参数；泥石流冲击力的估算方法国内外都以动量理论为基础,区别主要体现在经验系数取值上,巨石冲击力的计算则都考虑了拦挡建筑物的特点.

Comparison of methods used at home and abroad to estimate the key parameters of a debris flow

The density,velocity and impact force are three key parameters among those representing the characteristics of debris flow dynamics.Following review of literatures about estimation of those parameters at home and aboard,the methods for estimating these parameters are summarized and compared.The results show that there is no method applied to all kinds of debris flows in the world,and that present empirical equations for the three parameters can only be applied locally due to the complexity of the constitutes and the movement of debris flows.At present,it may be the most practical to establish different empirical equations according to the specialty of debris flows at different areas.The statistical methods to establish the multivariable equations considering particle size groups may be more resonable among the estimations of density.The empirical equations for a debris flow’s velocity are different among China,former Soveit Union and the Western countries.The former two is based on the Manning’s equation,and the Western countries use the forced vortex equation with superelevation in channel bends as the major parameter.Momentum theorem is the basic theory to estimate the impact force in the world,whereas differences lie in the empirical coefficients.The characteristics of the blocking structures are generally taken into account in terms of the impact of boulders of debris flows.