摘要
落石是我国山区重要灾害之一,棚(明)洞是抵御滚石冲击的重要措施。在实际工程应用中,棚(明)洞结构被落石砸坏的案例屡见不鲜,然而目前有关棚洞抗冲击性能的研究较少。文章借助ANSYS/LS-DYNA有限元分析软件建立了山区常见的悬臂式棚洞结构模型,并对滚石冲击荷载下的悬臂式棚洞的动力响应过程进行了仿真分析,研究其在冲击作用下的受力变形特性。研究结果表明:(1)冲击力荷载作用下,悬臂式棚洞中会产生冲击波,其传播会使结构产生应力和变形震荡;(2)棚洞结构不同部位达到最大应力的时间有所不同;(3)悬臂式棚洞的最危险部位在立墙顶部内侧与平板交接处和立墙下半段位置,实际工程中应采取局部加强措施,以保证结构的安全性;(4)冲击作用完成后棚洞结构内部的残余应力比较大,因此其顶部落石需要及时清理。该研究成果可为悬臂式棚洞的合理设计和施工提供重要的参考依据。
Roekfalls are serious hazards in mountainous areas, and cantilever shed tunnels are a key measure against the impact of rolling stones. While in practical engineering it is very common for cantilever shed tunnels to be damaged by falling rock, few studies on the properties of the cantilever shed tunnel against the impact of falling rock have been conducted so far. In this papel, using ANSYS/LS-DYNA finite-element analysis software, a model of the common cantilever shed tunnel found in mountainous areas was established and a simulated analysis of the dynamic response process of the cantilever shed tunnel against the impact of falling rock was carried out to study the resulting deformation properties. The study results show that： 1） under the impact of falling rock, shock waves are generated in the shed tunnel and the transmission of these waves will result in stress and deforming vibra- tions; 2） the amount of time to reach the maximum stress at different parts of the shed tunnel is different; 3） the most dangerous places in the cantilever shed tunnel during a rockfall are the junction of the inside top wall and the plate as well as the lower part of wall, so that local strengthening should be adopted in these areas to ensure the safety of the structure; and 4） larger residual stress will remain inside the shed tunnel after the impact of the falling rock, so clearing of the fallen rock at the top of the tunnel should be undertaken in a timely manner.
出处
《现代隧道技术》
EI
CSCD
北大核心
2015年第2期155-159,共5页
Modern Tunnelling Technology
基金
国家自然科学基金项目(No.40872181)
陕西省重点科技创新团队计划项目(2013KCT-20)
中交股份科技研发项目(2011-ZJKJ-04)
关键词
悬臂式棚洞
滚石冲击
动力响应
仿真分析
Cantilever shed tunnel
Impact of falling rock
Dynamic response
Simulated analysis
