基于原位模型的泥石流冲击下拦砂坝动力响应研究

Dynamic Response of Sand Dam Under Debris Flow Impact Based on In-situ Model

以某条泥石流沟为原型,建立了泥石流与拦砂坝的三维计算模型,开展了泥石流与拦砂坝三维模型的流固耦合研究,选取最大Mises等效应力及最大位移作为评价指标,得到了泥石流体仅会对拦砂坝迎流面一定深度范围产生较大影响,超出此范围影响较小,并给出最大Mises等效应力及最大位移沿拦砂坝竖向及横向分布规律:坝趾及坝踵节点最大Mises等效应力均与泥石流重度呈正相关;当进口泥深相同时,坝趾及坝踵节点的最大Mises等效应力与泥石流流速呈正相关;当进口单位时间流量相同时,坝趾及坝踵节点的最大Mises等效应力与进口泥深呈正相关。坝趾节点最大Mises等效应力随着时间的推移呈现先增加后基本保持不变;而坝踵节点最大Mises等效应力随着时间的推移呈现先增加出现峰值以后再减小。

Taking a debris flow gully as a prototype,a three-dimensional calculation model of debris flow and sand bar was established,and the fluid-solid coupling study of the three-dimensional model of debris flow and sand bar was carried out.The maximum Mises equivalent stress and the maximum displacement were selected as evaluation indicators.It is found that the debris flow will only have a large impact on a certain depth range of the upstream face of the sand bar,and the impact beyond this range is small,the maximum Mises equivalent stress and the maximum displacement along the vertical and horizontal distribution of the dam are given:The maximum Mises equivalent stress at the toe and heel nodes are positively correlated with the unit weight of debris flow;When the inlet mud depth is the same,the maximum Mises equivalent stress at the toe and heel nodes is positively correlated with the debris flow velocity;When the unit time flow at the inlet is the same,the maximum Mises equivalent stress at the toe and heel nodes is positively correlated with the inlet mud depth.The maximum Mises equivalent stress of the dam toe joint increases at first and then remains unchanged with the increase of time;However,the maximum Mises equivalent stress of the dam heel node increases at first and then decreases with time.