坝后淤积条件下泥石流冲击拦挡坝动力响应研究

Study on Dynamic Response of Debris Flow Impact on Check Dam with Sediments

拦挡坝有效库容和泥石流冲击力是泥石流实体拦挡坝设计的重要指标,现有实体拦挡坝在泥石流反复冲击作用下淤积甚至填满,会对坝体调控能力产生重要影响.为此,基于理论分析和物理模型试验,开展坝后淤积条件下泥石流冲击实体拦挡坝动力响应研究,推导坝后淤积条件下泥石流速度衰减率、坝体拦挡率的无量纲计算公式,并建立考虑空间分布特性的坝后淤积条件下泥石流冲击力计算模型.结果表明:泥石流速度衰减率和坝体拦挡率与淤积体高度/淤积长度比值和泥石流相对容重呈正相关;泥石流冲击力静动荷载组合计算模型能较好反映坝后淤积条件下泥石流冲击力的组成和分布特征.上述研究可为泥石流实体拦挡坝工程设计提供理论及技术支持.

Effective reservoir capacity of retaining dam and impact force of debris flow are important indexes for the design of entity check dam of debris flow.Deposits or even fills in the existing entity check dam under repeated impact of debris flows,have great influence on the control ability of dam body.In this paper,based on theoretical analysis and physical model test,dynamic response of debris flow impinging entity check dam under the condition of silting behind dam is studied,dimensionless calculation formulas of velocity attenuation rate and retaining rate of dam body under the condition of silting behind dam are derived,and calculation model of impact force of debris flow under the condition of silting behind dam considering spatial distribution characteristics is established.The results show that the velocity attenuation rate and dam retaining rate of debris flow are positively correlated with the ratio of silt height to silt length and the relative density of debris flow.The combined calculation model of impact force and static and dynamic load of debris flow can better reflect the composition and distribution of impact force of debris flow under the condition of silting behind the dam.This study can provide theoretical and technical support for the design of solid debris flow retaining dam engineering.