MEASUREMENTS OF GROUND MOVEMENT AND LINING BEHAVIOR ON THE LONDON UNDERGROUND AT REGENTS PARK

An investigation of ground movement and tunnel lining behaviour was carried out during the construction of the Fleet Line of the London Underground at Regents Park. For two tunnels, 4.15 m in diameter, constructed with expanded concrete linings at depths of 34 m and 20 m, 5 mm and 7 mm of surface setlement respectively were caused with a trough of settlement some 50-65 m wide at right angles to the tunnel axis. Comparing the settlements at various depths with those obtained for a tunnel of the same line constructed with cast iron linings at Green Park it was concluded that settlements for an expanded concrete lining were a little less than those for a cast iron one, which is to be expected in view of the more rapid rate of progress for the concrete lining and the fact that the ground is supported immediately after the passage of the shield. After a year, load cells at the axis and the crown of the lining showed that 0.51 and 0.31 of the overburden pressure had developed at these positions.