Measured Analysis on Surface Deformation and Influence of Cutter Torque for Twin Shield Tunnelling in Silty Sand

Table 4

Maximum torque values of different cases.

Case	Cutterhead diameter (m)	Soil properties	Maximum torque (kN·m)
Hangzhou Metro line 6	6.2	Silty sand	3366
Metro Izmir, Turkey	6.52	Sandy gravel	5200
London Heathrow Airport Tunnel	9.15	London clay	18842
Hangzhou Metro line 2	6.17	Muddy silty clay	2082