Particularity and Prediction Method of Ground Settlement Caused by Subway Tunnel Construction in Permafrost Area

Abstract

During the construction of subway tunnels in permafrost areas, there are more factors of permafrost deformation in the deformation of rock stratum and ground settlement above the tunnels. Due to the frost heave effect of soil freezing in winter and the thawing phenomenon of frozen soil during thawing and thawing in spring, the ground settlement will occur, so the law of ground settlement caused by subway tunnels and its impact on ground construction facilities are more complex. The characteristics of surface heave caused by frost heave in winter and thawing caused by thawing in spring are studied. The evaluation method of ground thawing caused by subway tunnel construction in permafrost area is given. The ground settlement during tunnel construction in seasonal permafrost area is studied through specific engineering examples. The research shows that the ground settlement caused by tunnel excavation in this case area accounts for 53% of the total ground settlement, the ground settlement caused by frost heave accounts for 27% of the total ground settlement, the ground settlement caused by thawing and thawing of tunnel frozen soil accounts for 20% of the total ground settlement. The research results can provide reference for the understanding of ground settlement caused by tunnel construction in permafrost areas and its disaster protection.