低碳养护条件下隧道衬砌脱空治理的复合加固技术研究OA

In response to the structural performance degradation and recurrent maintenance caused by voiding behind linings in operating highway tunnels,this study—based on the Ma'aoling Tunnel of the Yongtaiwen Expressway—proposes and validates a composite strengthening technique featuring the synergistic action of grouting-steel straps-flexible mesh.The method restores the lining-surrounding rock contact conditions through grouting,and further leverages the confinement and load-sharing mechanisms provided by steel straps and flexible mesh to achieve overall reinforcement of voided zones and suppression of crack propagation.Consequently,it reduces repeated repair demands and associated resource consumption driven by progressive deterioration.Considering the structural characteristics of tunnel linings and the service environment,a finite element model representing lining voiding conditions was established for comparative analysis.The results indicate that voiding at the arch shoulder significantly weakens the load-carrying capacity and safety reserve of the lining,and is prone to inducing localized stress concentration and damage evolution.After applying the composite strengthening system,both the load-carrying capacity and safety reserve of the lining are markedly improved;the mechanical responses at critical locations are effectively mitigated,and the deterioration trend is restrained.Based on the engineering logic of maintenance interventions during the operational period,the study further suggests that this composite technique has potential energy-saving,resource-reduction,and emission-mitigation benefits,by reducing the frequency of repeated maintenance,lowering material and mechanical energy inputs,and shortening traffic-control durations.