【摘要】 防落石柔性棚洞主要由型钢拱架和环形网组成,从现有的研究成果看,柔性棚洞内部构件荷载传递路径中存在薄弱环节,造成构件间的刚度不匹配,导致钢拱架发生了较大的侧向扭曲塑性变形,增加了柔性棚洞使用期间的维护费用,工程应用存在局限性。为优化设计柔性棚洞,降低钢拱架的塑性变形,在开展了柔性棚洞足尺模型试验和数值建模研究的基础上,利用数值模型对柔性棚洞在落石冲击作用下内部构件的耗能性能进行了分析,并在与试验成果进行对比研究的基础上,提出了柔性棚洞的改进措施。数值计算结果表明:相比现阶段设计的柔性棚洞,改进后柔性棚洞中构件吸收的能量趋于均衡化,钢拱架上吸收的能量明显减少,侧向扭曲塑性变形显著改善。最后对改进后的柔性棚洞进行了参数化分析,提出了柔性棚洞的优化设计方案。更多还原

【Abstract】 The flexible rock-shed for rockfall protection is composed of a steel vaulted structure and ring nets. The existing researches show that the stiffnesses of the rock-shed internal components are mismatched and the most serious plastic distortion occurs on the steel vaulted structure because of some weak components in the flexible rock-shed obstructing the load transfer path under the impact of rockfall. These defects would increase the maintenance cost and limit the engineering application. In order to optimize the flexible rock-shed and decrease the plastic distortion of the steel vaulted structure,a numerical model was employed to investigate the energy absorbed by each component in the flexible rock-shed based on the results of full-scale model experiments and numerical simulations,and a design method was presented to improve the connections between the components of the flexible rock-shed. The numerical simulation results show that: compared to the original flexible rock-shed,the energy absorbed by the steel vaulted structure of the improved flexible rock-shed is significantly decreased and the distortion is improved. In addition, a parametric study for the improved flexible rock-shed was implemented and an optimum design was presented.更多还原