Abstract: Studies of the performance of the tunnel lining structures under high water pressure is important to the optimization design of tunnel supporting structures. This paper presents a case history of the tunnel supporting study between stations Bingjiang Road and Wutang Village, Nanjing No. 3 Metro Line. The performance of the composite lining structure has numerically studied under the most unfavorable loading conditions. The results indicate that the cross section of the lining structure can be optimized. From the side wall to the top of the arch should be connected with circular arch with small radius so that the water pressures on the tunnel can be optimized. The small radius design also avoids the potential heave of the composite lining structure under the high water pressures. The resultant cost is not significant.

Key words: Nanjing Metro, Composite Lining, Composite lining；Crosssection Optimization, Numerical Analysis