Study on Unified Time-space Method of Calculating Stratum Deformation with Changing Tunnel Excavation Parameters

At present the time effect is not considered in calculation of stratum deformation caused by tunnel excavation and changing of tunnel excavation parameters is even more difficult to be considered in such calculation.In this paper,on the basis of the stochastic medium theory and in view of stratum settlement caused by element excavation and time-space development of upper stratum deformation,the unified stratum deformation calculating equation is deduced,which takes into account changing of construction parameters such as the tunnel excavation speeds,geological conditions and stratum losses.A numerical example shows that the deduced calculating method is of good reliability.The time-space rules of stratum deformation are discussed.When the construction parameters and geological conditions are changed,there will occur permanent longitudinal deformation at stratum interfaces.