地冲击荷载作用下等跨正交洞室动力响应研究

交叉洞室是地下防护工程常见的结构形式,它的安全稳定性能直接控制着整个防护工程的服役性能。通过数值模拟方法研究了典型等跨正交洞室在地冲击荷载作用下交叉区域的动力响应。研究表明,相同荷载、埋深和跨度条件下,交叉洞室的变形和破坏范围明显大于单向洞室;随着地冲击荷载峰值的增加,衬砌直墙交叉部位逐渐形成两个中心对称的V型相交塑性带,且衬砌拱脚和直墙底部逐渐屈服;随着洞室跨度的增加,交叉部位拱顶沉降量增量和圆拱最大质点速度逐渐增加,跨度较小时破坏主要集中在直墙部位,跨度较大时破坏主要集中在拱顶部位;地下洞室交叉部位的影响范围长度为距离交叉中心1.6倍的洞室跨度,交叉部位拱脚和直墙底部是受力薄弱部位,建议局部加厚支护,提高洞室的稳定性。

Dynamic response of equal span orthogonal caverns subjected to ground shock

The intersecting cavern is a common structural form of underground protective projects,and its safety and stability performance directly control the service performance of the whole protective projects.The dynamic response of a typical equal span orthogonal cavern subjected to ground shock is studied through numerical simulation.The results show that the deformation and damage range of the intersecting cavern are significantly larger than those of the unidirectional cavern with the same span under the same depth and load.With the increase of the peak value of the ground shock,two V-shaped intersecting plastic belts with symmetrical centers are gradually formed at the intersection of the straight wall of linings,and the arch foot and the bottom of the straight wall are gradually yielded.With the increase of the cavern span,the increment of the vault settlement and the peak particle velocity of the arch at the intersection increases.The damage mainly focuses on the straight wall of small-span tunnel,and on the vault of large-span tunnel.The influence range of the tunnel intersection is 1.6 times the tunnel span from the intersection center,and the arch foot and the straight wall bottom of the intersection are the weak positions.Locally thickening the supporting structures is suggested to improve the stability of the tunnel.