Study On Characteristics Of Earth-Pressure-Balance-Ratio Control Of Shield

Earth pressure balance (EPB) shield was a tunnel boring machine which widely used for shield construction. The cutting face stability of shield directly affects the construction quality of tunnel. At present, there were two control methods for cutting face stability, the one was management of earth pressure balance and the other one was management of soil excavation volumes balance. But the former control standard was not clear and the later real-time was poor. Therefore, some academics have brought forward an Earth-Pressure-Balance-Ratio (EPBR) control method of shield, as an auxiliary management method, which used to control cutting face stability. The method had some advantages, such as clearly control standard, easily detected parameters, strong real-time property, etc. However, the method effect on the thrust balance of shield, was merely based on theoretical analysis and engineering data. The method has never been done with experimental study. Thus, it's necessary to launch an experimental study on the characteristics of EPBR control for providing references to auxiliary manage stratum stabilization.However, it was difficult to make some experimental study on real shield in consideration of safety and economy. Therefore, this paper combined simulation experiment system of EPBR control of shield and simulation model of EPBR control of shield for launching study of the characteristics of EPBR control. The main works and results can be described as following:A control structure of EPBR and an implemented method of rotating speed control were designed, which made the SES apply to the research of the EPBR control.The validity of the EPBR control which maintain stratum stabilization was verified, by studied the anti-interference characteristics and step response characteristic of EPBR control on the simulation experiment system. Then, the influence of variation of EPBR to earth pressure stability was studied. The conclusion was that the amplitude of EPBR of shield should gradually be adjusted.The anti-interference characteristics and step response characteristic of EPBR control on the simulation model were done. And the feasibility of the simulation model which used to study the characteristics of EPBR control was verified, by contrasted the simulation results and the simulation experiment results. Then, different forward-velocity effect on anti-interfere ability of system and construction parameters of shield were researched. The qualitative conclusion was that set of forward-velocity should reconcile the anti-interfere ability of system and the driving power of the conveyor.