Abstract: The Taining tunnel is characterized as a super long and has a large crosssection. It is deeply buried with a high ground stress. The construction of this tunnel is a challenge. To seal off large volume of groundwater, a number of techniques are used: real time sealing; preventive curtain grouting; radial grouting; and grouting with gunny bags and strings bags. The adverse geological and groundwater conditions are detected by a comprehensive prediction method in combination of both long and short distances. The rock burst hazards was minimized by following methods: preventive geostress relief; controlled blasting; expansion anchoring; shotcrete with wire mesh; steel rebar reinforced rib; and shotcrete with super finegrained zeolite concrete additives. The ventilation concerns in the long large sized and deeply buried tunnel during the construction and the operation are addressed by the inclined shaft with sectional vertical ventilation technique. The research methodologies, approaches and conclusions of this case study can be used for other tunnel construction under similar conditions.

Key words: Long large sized and deeply buried tunnels, Tunnel construction, Pressurized groundwater intrusion, Ventilation, Critical construction technologies