This paper presents a case study of the effects of changed and severe geological conditions on trend of construction of lot number 1 of Qomroud Long Tunnel (QLT1) in Iran. Initially, drill and blast method was selected as construction method based on results from initial stage geological investigations. Construction of QLT1 started from three faces simultaneously: main tunnel and access tunnels no. 1 and 2. The instability problems were encountered during excavation of the tunnels. Following major instabilities construction of the tunnels was stopped and a complementary geotechnical investigations was carried out. Medium to hard rocks in primary geological-geotechnical profile replaced by weak to medium rocks with near to 1.50 km of fine-grained saturated soils. Results from new investigations presented in this paper and some geological-geotechnical considerations proposed to continue construction of the QLT1.
|Publication status||Published - 2005|
|Event||Tunnel Designs and Systems Engineering International Conference - Basel, Switzerland|
Duration: Sep 10 2005 → Sep 13 2005
|Conference||Tunnel Designs and Systems Engineering International Conference|
|Period||9/10/05 → 9/13/05|