In the construction of hydraulic tunnel

the engineering quality problem is often caused by concrete cracks and insufficient thickness of roof lining. This problem attracted great attention of the most engineers that whether the structure performance of this kind of lining can meet the design criteria or not

especially under unfavorable conditions. Based on the onsite inspections of the lining defects in Baishanzui tunnels

the model and size of the defects are analyzed with FLAC program. The study shows that the defects have obvious adverse influence on the stability and safety of the tunnel lining

however

if a backfilling grouting is carried out and the cracks are repaired

the integrality of lining is restored

the behavior of lining will be improved and can meet the design criteria as well. 