衬砌背后空洞对不对称连拱隧道结构安全性影响分析

Study on the Safety of Asymmetric Multi-arch Tunnel with Voids behind Lining

为了解决不对称连拱隧道衬砌背后空洞病害治理的工程难题,通过模型试验和扩展有限元法,研究空洞影响下不对称连拱隧道结构破坏演化规律,并提出衬砌背后空洞治理措施。研究结果表明:不对称连拱隧道裂缝最先出现在中墙底部与仰拱交接处外表面。无空洞时,大断面隧道拱部与中墙顶交接处出现裂缝;衬砌背后存在空洞时,大断面隧道右拱腰空洞右侧边缘出现裂缝。大断面隧道的跨度更大,中墙底部与仰拱交接处外表面最早开裂,其内表面结构被压溃。通过扩展有限元法能够有效模拟不对称连拱隧道衬砌背后空洞影响下结构破坏规律,建议对连拱隧道中墙顶部和拱部空洞及时进行治理。

In order to solve the problem for treating the defects of voids behind the lining of asymmetric multi-arch tunnels.Model test and extended finite element method were conducted to examine failure law of asymmetric multi-arch tunnel linings,and the control measures of the voids were put forward.The findings show that for the asymmetric multi-arch tunnel,the cracks were noted to extend firstly in the external lining at the bottom of the central wall connected with the invert.In case of lining without voids,the crack appeared on the top of the central wall connected with the arch lining of the large-section tunnel,in case of lining with voids,cracks appeared on the right side of the void on the right haunch of the large-section tunnel.The primary cracking and crushing occur at the bottom of the central wall connected with the invert of the large-section tunnel.The extended finite element method can effectively simulate the failure induced by voids behind the lining of asymmetric multi arch tunnels.It is suggested that the voids at the top of the central wall and the arch of multi-arch tunnel should be treated in time.