碎屑流冲击下柔性防护网的力学简化模型

A simplified mechanical model of flexible barriers under granular flow impact

柔性防护网是一种广泛应用于碎屑流防治的防护结构,目前缺乏综合考虑碎屑流冲击荷载组成特征及支撑绳受力特征的力学模型对其防护特性进行评估。基于碎屑流冲击拦挡结构的2种冲击模式,并考虑动、静及摩擦冲击荷载的组成,构建碎屑流的冲击荷载计算模型,并在考虑碎屑流不同冲击阶段和冲击模式的基础上,结合索结构力学,建立考虑碎屑流荷载组成和支撑绳受力特征的柔性防护网力学简化模型。对比碎屑流冲击柔性网的室内滑槽模型试验结果发现,底部支撑绳冲击荷载计算结果比试验值偏大,坡面堆积工况下的冲击荷载和柔性网受力计算结果基本符合试验结果,而连续冲击工况的计算结果大于试验结果。总体上,力学理论模型可以有效地描述其余支撑绳上所受荷载的非线性分布特征,且计算结果偏保守。

Flexible barriers are a kind of protective structure widely applied in granular flow control,but there is no a comprehensive mechanical model to evaluate the protective characteristics of flexible barriers considering the composition of granular flow impact loads and the mechanical characteristics of supporting ropes.In this paper,a calculation model of the impact load of granular flow was established based on two kinds of impact modes of granular flow impact retaining structure and considering the composition of static,dynamic and frictional impact loads.Finally,combined with cable structure mechanics,a simplified mechanics model of flexible barriers considering the force characteristics of the supporting ropes and the combination of granular flow loads was constructed considering different impact stages and impact modes of granular flow.The comparisons between the calculation results by the proposed model with indoor chute model test results of granular flow impacting flexible barriers show that the impact load calculation results of the bottom support rope are larger than the experimental values,the calculation results of the impact load and the flexible barrier force under the slope accumulation condition are in agreement with the experimental results,and the calculation results under the continuous impact condition are greater than the experimental results.In general,the mechanical theoretical model can effectively describe the nonlinear distribution characteristics of the loads on the remaining support lines,and the calculation results are conservative.