Study on the Mechanical Characteristics of the Screw Driving Torque during the Emptying of the Shield Soil Bin

Abstract

This article studies the changing law of the driving torque of the screw conveyor during the emptying process of the earth pressure balance shield chamber. First, the discrete element method of discrete medium theory and 3D software SolidWorks were used to create the research object and the screw conveyor model, and then the model parameters were determined and calibrated through numerical calculations and indoor experiments. The final numerical calculation results show that: 1) the screw torque will drop in waves with the increase of the calculation time. When the screw conveyor rotates at 360 deg/s, the calculated screw torque fluctuation amplitude is small; 2) when the number of particles in the soil bin is reduced to a certain extent, the use of a higher screw speed to improve the “dumping soil effect” is of little significance; 3) the negative exponential function can be used to better fit the decrease of screw torque with time; 4) for the bulk medium, for a given particle size and screw structure, there is a suitable speed, so that the effect of “machine-soil collision” is small, and the torque change of the screw is relatively stable.