Modeling and analysis of thrust force for EPB shield tunneling machine

Thrust force is an important parameter for the design and operation of earth pressure balance (EPB) shield tunneling machine. The analysis of in-situ data indicates that the conventional thrust force estimation model based on an empirical equation gives rather rough result. In order to reduce uncertainties, composition analysis and corresponding calculation of thrust force are proposed. Laboratory test with a Φ1.8 m EPB shield tunneling machine and calculation result of the new model have been compared. The new model has been improved step by step based on experimental result as well as the further analysis of the working principle of shield excavation. The relative error between the experimental thrust force and the calculation result with the final model is reduced to 3% at the smooth stage and 4% at the trembling stage. The influences of cutting ratio, hatch ratio and equivalent earth pressure on the total thrust force have been investigated.