1 shield profile
Beijing subway line 4 between the Summer Palace and Yuanmingyuan tunnel construction, the use of Japan's Komatsu company produced articulated soil pressure balance shield. It will cross the gravel composite stratum, advancing distance of about 1.5km. the main parameters of the shield are, diameter: Ф6140mm; length: 8570mm; advancing speed: 0~8.5cm/min; total thrust: 37730kN. articulated soil pressure balance shield main components of the function and features are as follows:
(1) the large cutter plate is driven by nine cutter plate motor, and then the cutter plate is controlled by five frequency converter to control the cutter plate. The cutter motor is controlled by 5 sets of frequency converters to realize the selection and switching of cutter speed. The speed of the cutter disk has five gears of 0.5, 0.7, 1.1, 1.6, 2.2r/min.
(2)The screw machine is driven by a hydraulic motor, which can be adjusted steplessly by the proportional valve, and the range of the speed of the screw machine is from 0 to 25r/min.
(3)The screw machine has the function of retracting and shrinking, and when it is in the maintenance, it can be retracted to shut down the front two screw machine gates, so that the screw machine can be used for the maintenance of the machine and the maintenance of the screw machine. machine gate, so that the screw machine and soil warehouse completely isolated.
(4) The propulsion system consists of 22 propulsion jacks driven by a propulsion pump and divided into four zones, and the propulsion speed is regulated by a proportional valve to adjust and control the oil pressure.
(5)The articulation system is driven by the articulation pump to drive the four articulation jacks to rotate up, down, left and right, and to adjust the propulsion attitude of the shield structure by full extension and full retraction.
(6) The assembling slewing and screw machine gate share one hydraulic pump, which is used in assembling/pushing state respectively.
(7) The belt conveyor is alarmed for 5s before running. The belt conveyor is equipped with pull-cord type stop knobs on both sides of the belt conveyor to stop the belt conveyor in case of emergency.
(8) shield tail grease set up before and after the two seals, by a shield tail grease sealing pump each divided into 6 points for pressure injection.
(9) There are two centralized lubricating oil and grease pumps (referred to as grease pumps) in continuous and intermittent two states of work were injected into the grease.
(10) There is a set of thin oil lubrication circulating pump (referred to as circulating pump) for lubricating oil filling.
(11) 2 mud pumps are used to adjust the flow rate of adding mud through the frequency converter. Add mud to the soil bin.
(12)The grouting system composed of grouting pump and mixer can carry out single liquid slurry pressure injection and has the function of cleaning pipes.
(13)There is one set of foam device which can generate foam and inject it into the soil in front of shield structure.
2 shield measurement and control system
2.1 shield control system
Shield control system mainly consists of PLC controllable programmable controller and display and operation terminals. PLC adopts the master-slave structure, there is a master station and two slave stations, and there is another set of grouting PLC.
PLC programmable controller adopts the Ans series of products manufactured by Mitsubishi Corporation of Japan. series of products. The shield using the A2USHCPU components is one of the world's most advanced miniaturized PLCCPU. It utilizes the Mitsubishi Shun Control Processor (MSP), which allows it to achieve speed and functionality comparable to many larger, more expensive PLCs.
PLC main station is located in the console, the main CPU model for the A2USHCPU-S1, with three display operation terminals, numbered GC1, GC2, GC7. which GC1, GC2 were operating shield equipment, as a backup for each other. The other GC7 operates the mud adding equipment.
1#Slave station is located in the shield structure, with three display operation terminals, numbered GC3~5, of which GC3 and GC4 operate shield jacks, and GC5 remotely operates grouting. 2#Slave station is located in the frame of the #2, with one display operation terminal (commonly known as touch screen), numbered GC6, operates grouting equipment.
The master station is connected to the 1# and 2# slave stations through two parallel cable loops (double loop network). The system adopts high-speed and reliable data communication, i.e. MELSECNET/Ⅱ data communication system, which uses two parallel cable loops to connect each PLC station, one of which is called the forward loop (or the main loop), and the other is called the reverse loop (or the secondary loop). When a cable break occurs in the primary loop, communication is automatically switched to the secondary loop to continue data communication. If both loops are broken or disconnected, communication continues between the connected stations except for the broken PLC.
The grouting PLC is independent of the PLC system, model FX1N-40MR, and exchanges signals with the main PLC station through the I/O port.
PLC configuration of the switching input/output components, analog input/output components, communication interface components and computer communication components. See Table 1 PLC Configuration Table for details.
2.2 Attitude Measurement and Control System
The attitude measurement and control system of the shield consists of 2 parts: shield and ground. The shield part is mainly composed of total station, prism, measurement interface, control unit, computer (monitor) and other equipment. The ground part is mainly composed of computers (monitors) and hubs and other equipment, the shield and the ground part of the signal through a pair of megabit modem (SDSL) for the connection.
The system realizes the automatic measurement of shield attitude by means of high-precision measuring instruments and special software, and the real-time data information can be obtained as follows:
①Coordinates and login name of the rear view point and station;
②Data of the measurement target;
③Pitch angle and turn angle of the shield during the measurement;
④Coordinate value, orientation and position of the shield in front of, in the middle of and in the back of the shield. Coordinate value, orientation deviation and other calculation results.
Inside the shield, the attitude signals measured by the total station and the shield construction signals acquired by PLC are integrated together in the measurement interface unit, displayed on the shield computer monitor and sent to the ground computer.
2.3 Detection System
According to the requirements of the shield structure measurement and control system, the basic detection instruments are configured to detect the analog signals: soil pressure, propulsion jack oil pressure, stroke, speed, four areas of oil pressure, oil pressure of the screw machine, rotational speed, articulated jack stroke, the cutter frequency converter output power, cutter sealing temperature, the screw machine gate opening, slurry pressure, slurry level, foam pressure, slurry level and slurry level. slurry level, foam pressure, slurry pressure, slurry flow rate, slope and angle of shield structure, etc. Configuration of the sensor (transmitter) *** more than 40 sets, see Table 2.
In addition, the detection of switching signals, configured more than 60 limits and more than 10 pressure relays. Mainly detect the assembling machine rotary left/right limit state, assembling machine cable tray left/right limit state, spiral machine extension/retraction state, spiral machine gate open/close state, air valve, mud valve, grouting valve, shield tail sealing valve open/close state, centralized lubrication grease level, shield tail grease level, and centralized lubrication grease pumps and pipelines, high/low pressure, shield tail sealing oil pressure is high or low, thin oil lubrication blockage and other signals. Signal.
2.4 Shield control and operation
2.4.1 Shield control
The main control of the shield: soil pressure balance control, sequence control and logic control.
①The soil pressure balance control is the main control of shield structure, when the soil pressure of the soil bin changes due to the disturbance of the soil body at the front side, it generates a deviation from the set value, and the deviation is reduced by adjusting the soil output through the automatic control of the rotary speed of the screw machine, so as to achieve the dynamic balance of soil pressure of the soil bin on the set value.
②Sequence control is in the state of propulsion, combined with timing, logic and other control conditions, so that the propulsion equipment in accordance with the normal working order: cooling pump operation → lubrication pump operation → cutter rotation → screw gate opening → belt conveyor rotation → screw machine rotation → propulsion jack action. Not according to the sequence of operation will not enable the shield to work properly.
③Logic control is the shield of each device according to a specific logical relationship between the development of the control, such as propulsion, if the occurrence of the blade torque overload or screw machine reversal, or propulsion speed is too fast or soil pressure exceeds the upper limit, according to the logic of the conditions will be to stop the propulsion jacks to extend the action. Another example of articulation must be in the articulation of the normal operation of the pump, the normal rotation of the cutter, articulation angle in the normal range of up, down, left, right rotation and full extension, full retraction and other controls, when a certain condition does not exist, the immediate end of the articulation control.
Interlocking conditions are indispensable for shield control, all the equipment in the shield involves interlocking conditions, such as when the power supply phase reversal, PLC communication failure, the equipment can not work. Some equipment action is interlocked, such as the front gate switch can not be spiral machine expansion and contraction and spiral machine out of the earth gate or assembling machine rotary control, and vice versa. These interlocking conditions in any case can not be lifted, and some equipment in abnormal conditions, can be lifted through the interlock to control a device alone, such as lifting the knife interlocking method to make the knife to stop running, you can control the operation of the belt conveyor or spiral machine alone.
2.4.2Shield operation
The buttons and knobs on the operation console can be used to operate the operation and stopping of the cutter, screw machine, belt machine, the selection of the cutter speed, the selection and expansion of the propulsion jacks, as well as the opening and closing of the screw machine gate, etc. A large number of other operations are carried out on the touch panel. And a large number of other operations are carried out on the touch screen.
There are two touchscreens on the console, arranged in a top and bottom row. It has: "running display", "detection display", "pump start", "advance", "auxiliary operation", "other settings", "abnormal display" and other screens. Normally, the upper touch screen can only operate some display screens and the lower touch screen can only operate some operation screens. When a touch screen fails, you can switch the screen of the failed one to the normal one, and then you can operate all the screens.
①"Operation display" screen: mainly display the state of each equipment, such as the blade motor, propulsion pump, screw machine, belt machine, shield tail grease pump, assembling and panning pump and other equipment running status; rear gate, front gate, pedestrian gate opening/closing status, screw machine jacks extend/retract, propulsion conditions, confirmation of the abnormal The state of the screw jacks is confirmed, abnormal conditions, and so on.
②"Detection and display" screen: mainly display equipment and construction data, such as cutter plate sealing temperature, shield attitude angle, articulation angle, propulsion stroke, thrust center position, thrust in the four zones, soil pressure, rear gate opening, cutter plate speed and torque, propulsion speed and thrust, screw machine speed and oil pressure, cutter plate revolutions, cumulative and so on. Accumulation, etc.
3. "Pump Start" screen: It mainly operates the starting and stopping of propulsion, auger, assembling and other pumps, and displays the operation status.
4 "Push" screen: mainly operates the selection of push jacks, four-zone hydraulic pressure increase/decrease, jack synchronization setting, push speed switching, etc., and displays the position of the thrust center, the four-zone thrust, the total thrust, the jack stroke, the push speed, etc., with additional operation guidance instructions.
5 "auxiliary operation" screen: the main operation of the articulation system and shield tail grease system equipment, and display the operating status of these equipment.
6 "Other Settings" screen: it consists of several sub-screens, which can set the parameters of the system and soil pressure. There are also two touch screens in the control room, one to operate the mud filling equipment and the other to operate the grouting equipment.
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