APPLICATION OF FULL SECTION EXCAVATION TECHNOLOGY IN THE CONSTRUCTION OF THE FIRST LAYER EXCAVATION OF EXTRA LARGE SECTION CAVERNS
The The non pressurized section of the flood discharge and ecological drainage tunnel in a certain hydropower station project belongs to a super large section underground cavern,which is divided into three layers for excavation and support construction.During the excavation and support construction of the first layer of the non pressure section of the flood discharge and ecological water release tunnel,the middle guide tunnel was first expanded on both sides in the early stage,and the full section excavation technology was adopted in the later stage.After comparing the above two excavation technologies,it can be concluded that the full section construction technology is feasible for the first layer of the super large section underground tunnel,which is conducive to improving efficiency,saving costs,ensuring safety,and also meeting the quality requirements.