不同拦挡距离对滑坡碎屑流冲击效应影响的离散元模拟

Discrete Element Simulation of the Effects of Different Baffle Distances on the Impact of Landslide-Debris Flow

通过离散元模拟方法研究了不同拦挡距离对滑坡碎屑流冲击效应的影响。结果表明:不同拦挡距离对碎屑流运动平均速度的影响呈下降趋势,拦挡距离越近,平均速度下降越快,拦挡距离越远,平均速度下降越慢;颗粒开始接触挡板,挡板距离越近,曲线近似于抛物线下降,挡板距离越远,曲线近似于线性下降;不同拦挡距离影响颗粒之间的最大平均接触力,曲线依然呈现先增后减再增再减的趋势;颗粒对挡板的冲击力可近似分为线性增大、持力阶段、线性减小3个阶段,挡板距离增大,线性增大阶段时间和持力阶段时间都有所减少,其中,持力阶段时间减小比线性增大阶段快,说明当建筑物离滑坡距离较近时,建筑设计要考虑最大冲击力以及后续持力阶段的作用效应,当建筑物离滑坡距离较远时,建筑的设计主要考虑最大冲击力对建筑物的影响。

For the purpose of obtaining the impact of landslide-debris flow,the effects of different baffle distances on the impact of debris flow were investigated with discrete element simulation. The results show that the influence of different baffle distances on the average velocity of debris flow is declining. The closer the baffle distance is,the faster the average velocity declines; the farther the baffle distance is,the more slowly the average velocity decreases. When the particles begin to contact the baffle,the closer the baffle is to the curve,the curve approximates the parabolic drop; the farther the baffle is,the curve approximates a linear decrease. Different blocking distances affect the maximum average contact force between the particles. The curve still shows the trend of increasing first,then decreasing,then increasing and decreasing again. The impact of particles on the baffle can be roughly divided into three stages： linear increase,holding stage,linear decrease. When the baffle distance increases,the time of linear increase and the holding time both decrease,while the decrease of holding time is faster than that of linear increase,which means that when the building is close to the landslide,the maximum impact and follow-up force stage effect should be taken into account in the architectural design; when the building is far fromthe landslide,the maximum impact on the building should be considered in the design.