Abstract: In order to study the influence of metro shield undercrossing tunneling on the deformation of doubleOtube （DOT） metro tunnel, the characteristics of the deformation of the DOT tunnel during Shanghai Metro Line No. 14 crossing underneath DOT tunnel on Line No. 6 twice are analyzed by insitu measurement. The results show that: (1) The shield undercrossing causes the vertical uplift deformation of the DOT tunnel and the torsional deformation of the crosssection, and it is difficult to control the track deformation caused by the crosssection torsion deformation. (2) The vertical deformation of the DOT tunnel is uplift deformation, the tunnel deformation is closely related to the incision position, and the curve near the intersection shows a humpshape after undercrossing. (3) The secondary crossing disturbance and superposition effect are significant, which are manifested as the extension of tunnel uplift deformation time, the increase of the accumulated deformation, and the change of the maximum deformation position during the two undercrossing processes. (4) The torsional deformation of DOT tunnel shows a wavy dynamic change distribution with the location of the shield tunnel incision, and there are multiple turning points, 〖JP2〗which is disadvantageous to the stress and deformation of the tunnel segment joint. Besides, the torsional deformation of the second undercrossing is smaller than that of the first undercrossing. (5) The time that the most unfavorable crosssection torsion of the DOT tunnel appears is different from that of the maximum deformation of the tunnel, and the most disadvantageous torsional position and the position where the maximum tunnel uplift occurs locate in different areas. (6) The grouting at the shield tail is effective in controlling the deformation of the DOT tunnel, but it leads to the increase of the torsional deformation of the tunnel.

Key words:  metro shield; insitu measurements, double O tube（DOT） tunnel; cross section torsion, relative torsion