碎屑流冲击刚性挡墙的力学模型研究

An impact model of granular flows on a rigid wall

山体滑坡或山体崩塌所产生的碎屑流常对拦挡结构造成严重的危害,通过室内模型试验研究刚性挡墙抗碎屑流冲击的力学模型。根据64组试验的碎屑流冲击过程,建立冲击力力学模型,计算出法向冲击力、切向冲击力及冲击力的作用高度。并将试验结果中的最大冲击力及残余力,与Ashwood模型、Adel模型及所提模型进行比较。结果表明,所提模型计算出的冲击力与试验结果更加吻合,Ashwood模型计算出的冲击力相比试验结果偏小,Adel模型的结果相比试验结果也较接近。在假设基底反作用力的位置为堆积区长度的2/3的条件下,冲击力作用高度与试验结果最接近。最大的法向力与切向力都随着基底摩擦角的增大而不同程度的增大,挡墙摩擦角只对切向力有明显影响。研究结果可为滑坡或崩塌碎屑流的防灾减灾设计提供参考依据。

Retaining walls are often seriously damaged by the dry granular flow resulted from a landslide or a collapse. Laboratory modeling tests were carried out, and an impact force model of the protective structure against the impact of granular flows,for calculating the normal impact force,the tangential impact force and the action point of the normal force,was established based on the granular flow impact process of 64 groups of experiments. The maximum impact force and the residual force obtained from tests were compared with Ashwood model,model and the proposed model. The results show that the impact forces calculated by the developed model and the Adel model are consistent with the experimental results,while the normal impact force calculated by Ashwood model is smaller than the experimental result. Assuming that the base reaction force acts at 2/3 of the deposition length of the dead zone,the action point of the normal force calculated by the new model is closest to the experimental result. Both the maximum normal force and the tangential force increase with increasing the base friction angle,while only the tangential force is obviously influenced by the friction angle of the retaining wall. The research results provide a reference for the disaster mitigation design of landslides or collapse granular flows.