地铁山岭隧道二次衬砌钢筋网防裂性能研究

Study on Anti-cracking Performance of Secondary Lining with Reinforcement Mesh in Metro Mountain Tunnel

为了定量分析采用防裂钢筋网提高地铁隧道衬砌结构抗裂性能的机理,以双线山岭隧道二次衬砌结构为研究对象,采用荷载结构法和杆系有限元数值模拟方案,定量分析了素混凝土二次衬砌结构开裂的临界荷载,进而获得了配置钢筋网的衬砌结构达到0.2 mm裂缝宽度时的临界荷载。分析表明,配置防裂钢筋网后,采用素混凝土的Ⅲ级和Ⅳ级围岩衬砌结构抗裂性能可分别提高22.4%和19.3%,V级围岩衬砌结构抗裂性能提高15.2%,且Ⅲ级和Ⅳ级围岩二次衬砌结构的破坏形式由脆性破坏变为延性破坏,从而提高了安全性能。

In order to quantitatively analyze the mechanism of anti-cracking reinforcement mesh for improving the crack resistance of tunnel lining structure,taking the lining structure of double-line mountain tunnel as the research object,the critical load of plain concrete structure cracking is obtained by using load-structure method and finite element numerical simulation,and then the critical load of lining structure with reinforcement mesh is obtained when the crack width reaches 0.2 mm.The analysis shows that the crack resistance of lining structure in grade ofⅢandⅣsurrounding rocks increases by 22.4%and 19.3%respectively after the anti-cracking reinforcement mesh is deployed,while the anti-cracking performance of secondary lining in grade of V surrounding rock increase by15.2%.Moreover,the failure mode of secondary lining in grade ofⅢand IV surrounding rock changes from brittle failure to ductile failure,improving the safety.