Analysis of Influence of Circumferential Blind Pipe Blockage on Water Pressure Behind Secondary Lining of Tunnel
To study the influence law of circumferential blind pipe blockage on the water pressure behind the secondary lining of tunnel,taking Wujiayuan Tunnel of Xi'an-Yan'an Railway as the study object,this paper uses FLAC3D for numerical simulation analysis of three-dimensional seepage under different waterhead heights.The results show that:(1)No matter whether the blind pipe is blocked or not,the pore water pressure at the arch crown of secondary lining of tunnel is at the maximum and that at the foot of wall is at the minimum.The pore water pressure presents a periodic change along the longitudinal direction of the tunnel,with the minimum at the blind pipe and the maximum in the middle between the two blind pipes.(2)After the tunnel blind pipe is blocked,the pore water pressure behind the secondary lining at the blocking place will rise in a short time and then gradually drop to be stable but higher than the water pressure when the blind pipe works normally.(3)With the increase of head height,the water pressure behind the secondary lining increases,and the blind pipe blockage does not change the distribution of water pressure.(4)The increase of water pressure behind the secondary lining varies with the degree of blind pipe blockage,and the order of water pressure from high to low is:bilateral complete blockage＞1/2 bilateral section blockage＞unilateral complete blockage＞1/2 unilateral section blockage＞no blockage.The study results can provide a reference for the maintenance of drainage system in mountain tunnels during operation.
NETL
NSTL
万方数据
