Abstract Restricted by site and construction period of ancillary structure of metro project, climbing excavation is often adopted. In order to determine tunnel face′s stability, the stabilities of working face in the cases of climbing excavation and horizontal excavation were analyzed by theoretical analysis and numerical simulation. With upperbound limit analysis, the affected scope and positions of failure zone were compared; the position of equivalent strain zone and the law of horizontal displacement changes were studied by simulation analysis. The results show that the scope of failure zone caused by climbing excavation was slightly larger than that by horizontal excavation and the position of affected zone is slightly lower than that by horizontal excavation; the horizontal displacement caused by climbing excavation within a scope of 0-1/3 height of tunnel face is slightly larger than that by horizontal excavation while it is slightly smaller beyond the scope of 0-1/3 height of tunnel face; the maximum horizontal displacements in the cases of climbing and horizontal excavation both occur at the place where is 1/3 height of work face and the de? formation of work face in the case of climbing excavation is not larger than that of horizontal excavation; the work face stabilities are mostly the same in the cases of climbing and horizontal excavation without regard to advanced support, and the work face stability is to be guaranteed with proper advanced support.
Abstract：
Restricted by site and construction period of ancillary structure of metro project, climbing excavation is often adopted. In order to determine tunnel face′s stability, the stabilities of working face in the cases of climbing excavation and horizontal excavation were analyzed by theoretical analysis and numerical simulation. With upperbound limit analysis, the affected scope and positions of failure zone were compared; the position of equivalent strain zone and the law of horizontal displacement changes were studied by simulation analysis. The results show that the scope of failure zone caused by climbing excavation was slightly larger than that by horizontal excavation and the position of affected zone is slightly lower than that by horizontal excavation; the horizontal displacement caused by climbing excavation within a scope of 0-1/3 height of tunnel face is slightly larger than that by horizontal excavation while it is slightly smaller beyond the scope of 0-1/3 height of tunnel face; the maximum horizontal displacements in the cases of climbing and horizontal excavation both occur at the place where is 1/3 height of work face and the de? formation of work face in the case of climbing excavation is not larger than that of horizontal excavation; the work face stabilities are mostly the same in the cases of climbing and horizontal excavation without regard to advanced support, and the work face stability is to be guaranteed with proper advanced support.
.Contrastive Analysis of Working Face Stability in Cases of Climbing Excavation and Horizontal Excavation[J] MODERN TUNNELLING TECHNOLOGY, 2018,V55(6): 94-100
2018, Vol. 55 