Construction behavior simulation of a hydraulic tunnel during standpipe lifting: Fid-Bau Portal

Construction behavior simulation of a hydraulic tunnel during standpipe lifting

Wang, Li-zhong / Wang, Zhan / Li, Ling-ling / Wang, Jin-chang

Highlights ► A numerical model with three loading phases corresponding to different construction phases was established. ► The radial and circumferential bolts and the interactions between segments and standpipes were investigated. ► Several critical issues of design including the inner force of liners and bolts and joint dislocations were analyzed. ► Special attention should be given to controlling of the lifting force, and protection measures should be adopted.

Abstract In China, the vertical lifting method is typically applied when building the water intakes of hydraulic tunnels in the seabed in China. In this work, a 3D finite element method was employed to investigate the dislocations of joints, the stress distribution of segments and the bolt inner force during the lifting of the standpipe. Because the loading conditions of the tunnel during different construction phases vary greatly, a numerical model with three loading phases corresponding to different construction phases was established. The radial and circumferential bolts and the interactions between segments and standpipes were investigated. The critical issues associated with the design and construction of hydraulic tunnel, including the inner force of liners, the inner force of bolts and joint dislocations were vigorously analyzed. The results indicated that due to the jacking up of ceiling segments and the imposition of the lifting force, the maximum dislocation, which occurred at the crown between the open ring and the adjacent ring, increased with the lifting force. Although the maximum dislocation was within the allowable range, the maximum inner force of bolts caused by dislocations was close to the ultimate strength. As a result, it was concluded that special attention should be given to controlling of the lifting force, and protection measures should be adopted to reduce dislocations.