Experimental study on thrust force during tunnel excavation with earth pressure balance shield machine

Thrust force is an important construction parameter during tunnel excavation with shield machine. It not only determines the advance rate but also influences other working parameters, such as cutter torque and rotation speed, etc. But so far, the research on thrust force, especially on frictional force between soil and shield tube, still does not go into enough depth. Therefore, a special model test scheme on tunnel excavation with earth pressure balance(EPB) shield machine is designed by the authors; while the silt sandy ground in Shanghai area is taken as prototype, then different parameters of shield machine and ground properties can be combined for testing. Based on the test results, studies are carried out to discover the variation law of thrust force, the mechanism of friction between soil and shield tube and its influence factors. Furthermore, a calculation formula of thrust force is deduced.