Abstract It is inevitable for shield construction to disturb surrounding strata, and it is particularly important to control deformation induced by shield construction. Based on a metro shield tunnel project, the laws of surface settlement for a twin-tube tunnel are studied by a theoretical analysis and numerical simulation, a modified ground settlement prediction method for twin-tube tunnels is put forward, and a comparison between theoretical data and measured data is conducted. The study results show that the larger the tunnel tube interval, the more obvious the“W” -shaped curve of the settlements; the smaller the tunnel overburden, the smaller the interval L required for the transformation from a“V” -shaped curve to a“W” -shaped curve of settlements; the better the soil conditions, the smaller the scope of disturbed strata and the more obvious the features of the“W” -shaped settlement trough; it is possible to use C=L/2i to describe the surface settlement distribution features of the twin-tube tunnel, and the surface set? tlement distribution curve develops from a“V”shape to that of a“Pot”and“W”with an increase of C, and the unsymmetrical“W” -shaped distribution is related to the relative interval of the tunnel tubes; and the predicted surface settlements calculated by the proposed formula agree well with the measured settlements induced by the construction of twin-tube tunnels.
Abstract：
It is inevitable for shield construction to disturb surrounding strata, and it is particularly important to control deformation induced by shield construction. Based on a metro shield tunnel project, the laws of surface settlement for a twin-tube tunnel are studied by a theoretical analysis and numerical simulation, a modified ground settlement prediction method for twin-tube tunnels is put forward, and a comparison between theoretical data and measured data is conducted. The study results show that the larger the tunnel tube interval, the more obvious the“W” -shaped curve of the settlements; the smaller the tunnel overburden, the smaller the interval L required for the transformation from a“V” -shaped curve to a“W” -shaped curve of settlements; the better the soil conditions, the smaller the scope of disturbed strata and the more obvious the features of the“W” -shaped settlement trough; it is possible to use C=L/2i to describe the surface settlement distribution features of the twin-tube tunnel, and the surface set? tlement distribution curve develops from a“V”shape to that of a“Pot”and“W”with an increase of C, and the unsymmetrical“W” -shaped distribution is related to the relative interval of the tunnel tubes; and the predicted surface settlements calculated by the proposed formula agree well with the measured settlements induced by the construction of twin-tube tunnels.
.Distribution Laws of Surface Settlement Induced by Shield Construction of Twin-Tube Metro Tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(2): 96-105
2017, Vol. 54 