| Full face hard rock tunnel boring machine(TBM)is a large tunnel excavation equipment suitable for hard rock geological environment,under the action of gripper system,thrust system and cutterhead system,depending on the revolving cutterhead to destroy rock,so that the whole section of the tunnel will be excavated and formed at once.The gripper and thrust system is one of the key subsystems of TBM system and is responsible for providing thrust force to TBM during excavation.At present,the existing TBM thrust system uses ration pump,during the thrusting,a large number of oil flows back tank through relief valve,increasing the heat of TBM,the gripper system uses constant pressure pump to supply oil,after the gripper support the surrounding rock,the pump needs to work at the minimum displacement to maintain the set system pressure,also increasing the heat of TBM,thus increasing the difficulty of high temperature geological construction.On the other hand,during the construction of TBM,constructor manually set the output force of the gripper cylinder in the gripper system and the restricted force in the thrust system by experience without considering the coupling relationship between the output force of the gripper cylinder,the output force of the thrust system and the surrounding rock type at the support,without considering the impact of sudden thrust load on the thrust system,causing a sliding accident of gripper and surrounding rock or a crushing surrounding rock accident,seriously affecting the construction schedule or causing mechanical and hydraulic damage.In order to reduce the power consumption of gripper and thrust system during thrusting,a study on energy saving control was carried out.To avoid the occurrence of skidding accidents and crushing accidents and improve TBM tunneling efficiency,a study of thrust coordination control was carried out.This issue was supported by National Key Basic Research and Development Program(973).In this paper,mechanical models of gripper and thrust mechanism of TBM were established,and the influence of partial load of cutterhead on propulsion system was analyzed.A strategy of partition synchronization control for thrust system was put forward,and its effectiveness was verified by experiment.Aiming at the problem of low efficiency in gripper and thrust system,load sensing and constant pressure control technology was introduced.Two energy saving control strategies were proposed,and new electro-hydraulic control systems were designed,and their validity were verified through simulation analysis.Aiming at two kinds of accidents existing in gripper and thrust system,three coordination control strategies were proposed,and their electro-hydraulic control systems were designed.The effectiveness of the strategies were verified by Co-simulation technology.The main research contents in this paper are as follows:1.The mechanical models of TBM host mechanism,main beam mechanism and gripper mechanism were established.The mechanical relationship between the thrust load,thrust cylinder,gripper cylinder and surrounding rock was analyzed,the formulas of force calculation of the right and left thrust cylinders under the condition of partial thrust load of cutterhead and the formulas of force calculation of the surrounding rock were deduced.It was found that the partial thrust load of cutterhead would cause the left and right thrust cylinders not to be synchronized.Therefore,the thrust hydraulic system of partition control was designed,and the strategies of partition general control and partition synchronization control of thrust system were proposed.2.Based on the effect of pressure protection of accumulator,the strategy of constant pressure gripper(CPG)and load sensing thrust(LST),and the strategy based on load-sensing and constant-pressure thrust and accumulator auxiliary gripper(LSCPGT)were proposed,and the partition synchronization control strategy was introduced into the thrust system of two control strategies.New gripper and thrust hydraulic systems were designed respectively,and their simulation models in AMEsim were established.Based on the construction data of the water supply project in Jilin Province,the simulation analysis of two new systems and the traditional gripper and thrust system composed of ration thrust(RT)and CPG system with partial thrust load was carried out.The results showed that both the system composed of LST system and CPG system and the system of LSCPGT could meet the gripper and thrust needs.However,LSCPGT system had no flow and pressure loss during high-pressure gripper and thrust,and had less pump system with better energy saving effect.3.The mechanical relationship between the thrust load on the cutterhead and the left and right thrust cylinders was analyzed.Combined with the mechanical analysis of the surrounding rock at the support,the control strategy based on restricted output force of thrust cylinders and constant output force of gripper cylinder(TRSC),the control strategy based on restricted thrust load force of cutterhead and constant supporting force of surrounding rock(CRSC),and the control strategy based on constant thrust load force of cutterhead and constant supporting force of surrounding rock(CCSC)were proposed.Their electro-hydraulic control systems were designed respectively,the models based on fuzzy PID technology were established by the co-simulation method of Simulink software and AMEsim software,and the coordination control performance of the three gripper and thrust system was simulated and analyzed when the surrounding rock type was V.The results showed that both CRSC system and CCSC system could avoid the accidents of skidding and crushing,both CRSC system and CCSC system could reduce the force fluctuations on the surrounding rock at the support,and the overshoot control was within 1%.CCSC system had a higher thrust speed,and could keep the thrust force of the cutterhead constant,but its thrust system had obvious flow impact when cutterhead encountered sudden thrust load.4.Based on the open TBM of Robbins type MB-332,gripper and thrust hydraulic system and thrust load simulation hydraulic system of the TBM test rig with scale diameter of 2.5m were designed.According to the control objectives of gripper and thrust system,the electronic control system of the test rig was designed,and the communication between controller PLC and controller Simulink and host computer WINCC was established,the visual operation interface of the test rig and the controller of gripper and thrust were designed,and the two proposed partition control strategies of thrust system were tested by TBM test rig.The test results showed that under the condition of partial thrust load of cutterhead,when the thrust system adopted traditional control,there was a significant displacement deviation between the left and right thrust cylinders,and when the partition synchronization control was adopted,the deviation range was only 1.8mm with the stroke of 272mm,which was better linear thrust performance. |
PDF Full Text Request