The construction method of earth pressure balanced shield has become the one of main trend for underground tunnel construction in metropolis. The torque on cutter head is by far higher than the one of Mud-water Pressure-adding Balance Shield

which is a common concern in the field of shield tunnel engineering. At present

the method of empirical estimation for torque of cutter head is adopted mostly

unfortunately

this method has a too wide estimation interval. For lack of experiences in construction and in consideration of construction safty

man cannot but use the ultimate value of torque to make the design of the assebling torque of shield

thus resulting in great waste in cost. According to the mechanism of torque formation

this paper studies the method to calculate the torques of every composition members respectively and then establish a model for the calculation of the torque on shield machine’s cutter head. Finally

the paper verifies the rationality of the model through an engineering case of shield construction in a subway project..