【摘要】 拦挡结构可以有效减小滑坡致灾范围、减弱致灾强度。文章以滑坡碎屑流为研究对象,通过对比模型试验和数值模拟结果,校正三维离散元模拟参数,进而研究不同坡脚角度和挡板高度对冲击力、最大水平运动距离的影响。研究结果表明:三个坡脚角度碎屑流冲击力的变化过程存在明显区别,坡脚角度为35°和45°时,冲击力时程曲线经历了两个显著的变化阶段:线性增大、线性减小。而坡脚角度为55°时,碎屑流冲击力时程曲线出现三个变化阶段:线性增加、恒力阶段、线性减小。挡板高度越高,恒力阶段的持续时间越短,冲击力线性减小阶段时间越长。小颗粒(2.5～10 mm)对挡板的冲击效应显著;中等颗粒(10～25 mm)随着挡板高度的增加,对挡板的冲击效应逐渐增大;而大颗粒(25～60 mm)作用在挡板上的冲击效应出现突变,与其他两种颗粒对比,整个运动过程冲击效应不显著。碎屑流的运程随着挡板高度的增加逐渐减小。对比三个坡脚角度下挡板的拦挡效果,坡脚角度α≤45°时,拦挡效果显著。更多还原

【Abstract】 Construction of resistive structures can effectively reduce the deposit area of landslides and weaken the intensity of hazard.In this study,the landslide-debris flow is examined by using the 3D discrete element method,whose parameters are calibrated by comparing the results of the model tests and those of the numerical simulations.The influence of different slope gradients and the height of barrier on the impact force and the maximum of the horizontal running distance are further studied.The results indicate that for the three experiments with different slope gradients there are obvious differences in the impact force variation processes.When the slope gradient is 35° or 45°,the magnitude of the landslide-debris flow impact force undergoes two significant stages:linear increase and linear decrease.When the gradient is 55°,there are three stages of change in the time-history curve:linear increase,constant force stage and linear decrease.The higher the height of barrier is,the shorter the time duration of the constant force stage,and the longer the linear decrease stage is.Small particles(2.5～10 mm) have significant impact effects on the barrier.With the increasingheight of barrier,the impact effect of the medium particles(10～25 mm) on the barrier gradually increases.The impact effect of large particles(25～60 mm) on the barrier has an abrupt change.Compared with other two kinds of particles,this impact effect is not significant during the whole motion.The running distance of the landslide-debris flow gradually decreases with the increasing height of barrier.Comparison of the resistance effects of the barrier under three slope gradients shows that the resistance effect is significant when the slope gradient α≤45°.更多还原