Based on field surveys on Sanyanyu debris flow gully in Zhouqu County and analysis of associated data, in this study it conducted an technical evaluation on performances of local building structures against debris flow. According to damage patterns,four types of house structures were sorted out for demonstration,which were rammed earth-wooden structure,brick-wood structure,brick-concrete structure and frame structure,typically subjected to two principal types of loading modes,either burying by silts or collapsing due to colliding.Comparison was made to ex-amine calculation differences between some of available equations,when actual measurement data collected from the Sanyanyu debris flow were used for calculation of debris flow impact incurred by both debris flow fluid and big boul -ders floating in debris flow body.Then it analyzed the derivations of these equations and interpreted the correspond-ing calculation results.For facilitating engineering and technical personnel to design structures with sufficient resist -ance to debris flow,a proposed equation then was introduced by integrating the depth of debris flow with dynamic effect of debris flow.The suggested expression was readily to set a proper value range for coefficients of dynamic effect and depth of debris flow in practice,and it had been verified by a case study for examining the design of a typical local rammed earth-wooden structure against debris flow in the Sanyanyu. The optimized simplification gave this method good advantages in a better understanding of its physical signifi -cance and its higher efficiency in determination of design load in engineered control of debris flow -prone regions. Moreover,it is quite technically feasible for engineers to gain some key prerequisite parameters to use the equation. For example,the value of debris flow depth could be substituted by an average value according to local historic ob -servations.And the values of dynamic effect could be determined by combination of the value of vertical slope of gully bed and the roughness coefficient.%基于舟曲县三眼峪泥石流灾害的实地考察和资料分析,对该地区常见的夯土木构、砖木结构、砖混结构和框架结构4类典型受损的结构形式进行了分析,确定建筑物的破坏模式主要为淤埋破坏和倒塌破坏.对现有的泥石流冲击作用计算公式进行了分类整理,以三眼峪泥石流实测数据为例对比分析整体冲击力和大石块冲击力的不同计算理论和计算结果.为便于工程技术人员进行房屋抗泥石流设计,提出了基于泥石流深度并考虑泥石流动力效应的设计计算方法,给出了以三眼峪泥石流为例的动力影响系数设计值和设计泥石流深度取值范围;并对当地典型夯土木结构房屋进行了泥石流安全性分析.此简化计算方法物理意义清晰,计算快捷有效,可用于泥石流多发地带的设计荷载计算,其关键参数泥石流深度可根据当地常年记录以统计值采用,动力放大值可根据沟床纵比降和沟床糙率系数确定.
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