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.