Research Of Water Pressure Distribution And Waterproofing Technology Of Shallow Excavation Subaqueous Tunnel

The Xiangjiang subaqueous tunnel of Changsha City is located in Changsha urban area, which connects main roads in the east and west areas. The Xiangjiang subaqueous tunnel is beneath the Xiangjiang River and has four lanes. It is constructed by shallow-buried-excavation method. On the background of the design and construction of the the Xiangjiang subaqueous tunnel, the seepage and stress field distribution around the tunnel and has been studied, as well as the tunnel waterproofing, drainage principles and drainage system. The main research results are as follows:(1) Considering seepage force inducd by tunnel drainage in the equilibrium equations, elastoplastic analytical solution of stress and displacement surrounding rock is derived, and put forward a new method of calculation plastic zone radius of tunnel surrounding rock;(2) Comparing the derived analysis solution with classical Lame’s solution, Kastner’s solution and FLAC numerical solution and find that the existence of seepage force can inlarge the plastic zone radius, effective stress and displacement of the surrounding rock, reflecting the phenomenon of osmosis can increase the effective stress of the surrounding rock, more classical analytical solution derived Lame’s solution, Kastner’s solution closer and FLAC numerical solution;(3) Combining experience of the exist underwater tunnel, the waterproofing and drainage of Xiangjiang underwater tunnel is proposed;(4) Determinig the Xiangjiang underwater tunnel waterproofing and drainage system that consists Grouting, waterproof layer, lining concrete, construction joints and deformation joints waterproof. The tunnel waterproofing system could water get into the tunnel from the primary support.