隧道衬砌掉块类缺陷结构安全性检算方法及整治技术方案

Safety Checking Calculation Method and Treatment Technical Scheme for Tunnel Lining with Block Falling Defects

隧道衬砌掉块类缺陷分布隐蔽、危害极大,若发现该类缺陷进行快速有效的安全性评估和及时整治至关重要。针对重整治轻评估的现状,结合工程实例,依据旧新两版《铁路隧道设计规范》,分别给出采用容许应力法和极限状态法进行该类缺陷结构安全性检算的流程和方法。经计算,极限状态法、容许应力法计算所得的衬砌结构最小厚度分别为20、25 cm,说明容许应力法计算结果偏保守,因此安全性检算时该方法尚不能摒弃,应综合考虑和对比两者的计算结果。最后给出了一种注浆加固填补衬砌掉块空洞的通用技术方案,为类似缺陷整治提供参考。

The defects of falling blocks in tunnel lining are hidden and harmful.If such defects are found,it is very important to carry out rapid and effective safety assessment and timely remediation.In view of the current situation of attaching importance to treatment but neglecting assessment,combined with engineering examples,and according to the old and new editions of the Code for design of railway tunnels,the processes and methods of the safety checking calculation of this kind of defective structures using the allowable stress method and the limit state method were given respectively.Through calculation,the minimum thickness of lining structure calculated by the limit state method and the allowable stess method is 20 cm and 25 cm respectively,indicating that the calculation result of the allowable stess method is conservative,so this method cannot be abandoned during safety check calculation,and the calculation results of the two methods should be comprehensively considered and compared.Finally,a general technical scheme of grouting reinforcement to fill the cavity of lining falling block was given,which can provide a reference for the treatment of similar defects.