防落石冲击柔性被动拦截网试验与数值分析

Test study and numerical analysis of flexible protective structure for falling rocks

针对目前柔性被动拦截网结构大量破坏的现状,开展原尺寸柔性被动拦截网落石冲击试验,研究系统整体的变形特征和传力机理,明确其3阶段的传力工作状态。采用显式动力算法,建立数值计算单元,模拟落石冲击整体结构的全过程,并与试验结果进行对比,二者结果吻合较好,表明该套数值计算方法的可行性;基于试验和数值仿真,得出系统变形、能量分布特点。在此基础上,开展多跨模型的数值仿真对比。分析结果表明:随着跨数增加,边跨的边界效应逐步降低,当采用5跨及以上模型作为等代模型时,位移和内力不需要修正;当采用3跨模型等代时,最大位移宜相应增大5%,冲击跨的上拉锚绳的拉力宜增大20%,端柱的上拉锚绳拉力宜减小30%。研究结果为今后柔性被动拦截网的设计提供理论基础。

For abundant damage of flexible protective structures, full scale model test carried out. According to the test results, study the transfer mechanism and deformation features of the system.In addition, a three-stage mechanical behavior was revealed. Used the explicit algorithm of LS-DYNA, simulation of the whole process of rockfall impact system, and compare with the experimental results, the results are in good agreement. Indicate the feasibility of numerical analysis. Based on the results of test and simulation, get the characteristic of displacement and energy distribution. On this basis,carry out the numerical simulation of multi-model, the results show that as the number of spans increase, gradually reduce the boundary effect of side span. When using five or more across as a simplified model of the original model, the displacement and internal forces do not need to be amended accordingly. When using three cross-simplified model, the maximum displacement should be a corresponding increase of 5%, the tension of anchor rope in impact across should be increased by 20%, the tension of anchor rope in end column should be reduced by 30%. The results build the foundation for flexible protective structures design.