落石冲击下轻型刚性棚洞结构力学响应

Mechanical Response of Light Rigid Shed Tunnel Structure under Rockfall Impact

为掌握钢架与玻璃钢顶板组成的轻型刚性棚洞在落石冲击下的力学性能和破坏模式,以实际工程中的轻型刚性棚洞结构为原型,利用动力有限元方法,对落石冲击下的轻型刚性棚洞的冲击行为进行研究。为分析不同情况下落石冲击行为的异同,考虑设立4种工况对计算结果进行对比,探讨不同工况对落石冲击下轻型棚洞结构的影响。结果表明:(1)随着落石冲击能量的增加,受冲击部位力学响应更加明显,但其它部位影响较小,说明落石冲击下结构的受力是局部力学响应;(2)在结构自重作用下,就高速铁路隧道限界而言,本次的轻型刚性栅洞的不利受力部位在钢架与纵梁结合部位,其次是玻璃钢顶部。

In order to grasp the mechanical properties and failure modes of a light rigid shed tunnel composed of a steel frame and a glass fiber reinforced plastic roof under the impact of falling rocks,a light rigid shed tunnel structure in actual engineering is used as a prototype and by dynamic finite element method,the impact behavior of the light and rigid shed tunnel caused by falling rocks was studied.In order to analyze the similarities and differences of the impact behaviors of falling rocks in different situations,four kinds of working conditions were set up to compare the calculation results,and the effects of different working conditions on the structure of light shed tunnels under falling rock impacts were discussed.The main conclusions are as follows:(1)With the increase of the impact energy of the falling rock,the mechanical response of the impacted part is more obvious,but the impact of other parts is smaller,which indicates that the structural force under the impact of the falling rock is a local mechanical response;(2)Under the weight of the structure,and for the boundary of the high-speed railway tunnel,the disadvantageous part of the light rigid shed tunnel is the joint between the steel frame and the longitudinal beam,followed by the top of the glass fiber reinforced plastic.