Study and Engineering Application of Waterproofing and Drainage System in Xiamen Subsea Tunnel

In order to provide the theoretical basis for design of waterproofing and drainage system for subsea tunnel in China,some key problems for design of waterproofing and drainage system were studied based on Xiamen Subsea Tunnel.By calculation of water flow into tunnel and theoretical analysis for effect of blocking grouting circle combined with engineering analogy,the design principle and project of waterproofing and drainage system for Xiamen Subsea Tunnel were performed.Two kinds of waterproofing and drainage styles,absolute blocking water and water discharge limiting,were adopted in the tunnel.The former style was used in the whole service tunnel and the unfavorable geology parts of the main tunnel,and the water pressure acting on tunnel lining was calculated with the total water head.The latter style was used in the favorable geology parts of the main tunnel,and the water pressure acting on the tunnel lining could be decreased to a certain degree.Blocking grouting circle,waterproofing lining structure,partition waterproofing system and drainage system constituted the waterproofing and drainage system for Xiamen Subsea Tunnel.Field practice indicates that the waterproofing and drainage system works perfectly and can be referenced by the similar tunnel engineering.