Study On Energy-saving Of EPB System In Shield Machine Based On Secondary Regulation Principle

Shield construction is the most efficacious method to construct tunnel now in the world. Earth pressure balance (EPB) shield is used most extensively in shield construction. In actual construction, the EPB shield often stops for the reasons of pipe installation, equipments maintenance etc. Reducing the energy loss caused by frequent stop is a very important measure of cutting off the whole energy consumption of the shield, so it is significant to research the energy-saving technology of EPB system. However, it is not economical or safe to research on the underground construction site, so experiments are done on an electro-hydraulic simulation system. It is expected to find out effective energy-saving methods through research on the electro-hydraulic simulation system of EPB system.The EPB system has great inertial mass of itself and it carries large amount of soil during work, that means it has enormous inertial power when rotating, while the pump-controlled-motor technology, which is widely adopted by EPB system at present, usually brake the system by the mean of decreasing the displacement of the oil-source pump and then make the system stop by friction, so the inertial power of the pivot and spiral blade is failed to be recovered and lost in vain, in addition, the violent friction between earth and spiral blade can cause systematic temperature rise and acceleration of the abrasion of parts. In order to solve these problems, a kind of hydraulic system based on secondary regulation principle which has a character of quick response and the ability of energy-recovery is proposed, it can be inferred this system would be superior to pump-controlled-motor's in the area of response speed and, what is more important, the function of inertial power recovery, which can reduce the construction cost and then improve the operational efficiency of shield machine.A lot of experiments are done on an electro-hydraulic simulation EPB system based on hydraulic power control principle. This simulation system has already been proved practicable and reasonable in principle, and it is convenient for simulation with high experiment efficiency.This thesis mainly studies the feasibility and rule of inertial power recovery during the braking of EPB system through the application of secondary regulation principle. At first, the constant-displacement way of energy-recovery is tested to prove the feasibility of inertial power recovery, then the constant-displacement way is regard as the basic way of energy-recovery to find out the influence that the parameters of system such as pressure of oil sources, displacement and rotation rate of secondary element have on the efficiency of energy-recovery; finally the disadvantages that exist in the constant-displacement way are analyzed, combined with the actual braking requirements of EPB system, the constant- torque way of energy-recovery is proposed and tested. Conclusions are made from experiments that the system based on secondary regulation principle have evident capacity of inertial power recovery; some parameters of system such as pressure of oil sources, displacement and rotation rate of the secondary element etc have different influence on the efficiency of energy-recovery; the constant-torque way of energy-recovery can make the system meet braking demands and can increase some certain resistance against load interference.