Various mechanical failures may occur during the construction process of the rotary drilling rig. Analyzed the common mechanical failures of rotary drilling rigs in sand layer construction.
The torque of the rotary drilling rig's power head is insufficient, the forward and reverse rotation speed of the power head is insufficient, and there is abnormal noise when the power head motor or reducer is running.
Insufficient torque of the power head can be considered from hydraulic and mechanical aspects: 1. Insufficient hydraulic pressure in the hydraulic system; Malfunctions in the power head motor, reducer, or gearbox.
The reasons for insufficient torque of the power head of the rotary drilling rig are as follows: 1. Insufficient pilot pressure or low safety valve setting pressure; Hydraulic system seal ring breakage, oil impurities or uncleanliness, filter element blockage; Damaged parts of the power head reducer; 4. The power head motor is damaged or there is a large amount of hydraulic oil leakage; Power head gear. The mechanical device of the box is damaged.
The general elimination method is divided into the following steps: 1. Detect the normal pressure of the main hydraulic system, indicating that there is no problem with the hydraulic system, considering the possibility of mechanical damage; When checking the hydraulic system circuit, first check the sealing ring. If it is damaged, it should be replaced in a timely manner. If the oil quality is not clean, the hydraulic oil should be replaced or re oiled. After using the filter, plug the filter plug and replace the filter element in a timely manner. Three. When inspecting the hydraulic system, it was found that there were a small amount of periodic abnormal noise in the reducer and motor during the operation of the power head. Remove the power head motor and inspect the motor and output shaft; 4. Remove the gearbox, remove the gearbox. When disassembling, attention should be paid to keeping the environment clean and disassembling strictly in the order of installation. Carefully inspect the interior of the reducer. If the gear is found to be lost, it should be replaced and the bolts, washers, and parts should be cleaned once.
The main failure phenomenon is: insufficient torque of the power head of the rotary drilling rig, low speed, and normal reverse rotation. The engine is working properly.
Generally speaking, insufficient hydraulic oil pressure, reduced hydraulic oil flow, or damage to mechanical transmission devices can lead to a decrease in torque and speed [2].
The main reason for this failure is: 1. The pressure of the safety valve of the power head oil seat filling valve is too low; 2. The pressure of the main valve power head control valve safety valve is too low; 3. Cavitation and internal leakage of the power head motor; Power head reducer malfunction; Power head large gearbox shaft failure.
The troubleshooting should be carried out according to the following steps: 1. Measure the combined pressure of the main pump. When the pressure is normal, the problem of insufficient oil pressure in the main pump should be ruled out; Clean the one-way valve and safety valve on the power head filling valve. Adjust the safety valve and replace the filling valve. If the fault is not resolved, the issue of filling valve and safety valve faults can be ruled out. Three. Replace the two main oil pipes on the power head oil seat. The test handle operates in opposite directions, and the fault cannot be eliminated. It can be determined that there is no problem with the main valve control valve; 4. Disassemble the motor, test the condition of the motor, it is normal, and troubleshoot the motor. 5. If all the above faults are eliminated, it may be caused by a malfunction in the power head reducer. The malfunction of the gearbox is usually caused by severe wear of the gears. After replacing the gears, normal operation can be restored.
The most common electrical fault of rotary drilling rig is that the depth measurement of the rotary drilling rig does not display. The main component of the rotary drilling rig depth measurement system is the encoder provided by P24V. When the encoder has a pulse signal, it feeds back to the controller through the A-phase and B-phase of the pulse signal. The signal is processed by the controller and then transmitted to the display screen to show the depth reading. If the power or signal line of the depth measurement encoder is disconnected, the encoder is damaged, or the confirmation signal of the controller is abnormal, the depth measurement display will not be read.
The main reasons for failure are as follows: 1. Loose, loose or detached connection between power and signal lines; The encoder is damaged due to excessive vibration or abnormal impact; The detector has no signal output.
During the drilling process, rotary drilling machines inevitably encounter problems such as hole collapse, pipe jamming, and falling objects. The above faults can be eliminated through methods such as backfilling and re drilling, suction and pulling of mud, and hook fishing. The following introduces the faults and handling methods that occur during the grouting process of rotary drilling rigs.
Pipe blockage is the most common phenomenon, caused by poor fluidity of concrete, various mechanical failures resulting in discontinuous pouring of concrete, long residence time in pipelines and pipe blockage, or concrete segregation due to water ingress into pipelines. When a malfunction occurs, the following three methods can be used to troubleshoot it.
Hammer the pipe flange. Hammer the flange of the conduit and shake the lifting rope up and down to clear the conduit. Connectable vibrators can be installed in some severe situations, but used at the beginning. Vibration can dredge, but the disadvantage is that the concrete may separate at the same time.
The steel bars have been compacted. If the clamping pipe is not far from the ground, steel bars over 25 meters can be punched.
Welding iron plates. The steel plate is welded outside the conduit, and when the conduit falls, the impact vibration between the iron plate and other clamps is cleared. Troubleshooting of Urinary Catheter Inhalation Malfunction
When water enters the pipe, a hissing sound of water flow can be heard inside the pipe. At this point, the leakage location should be quickly identified and buried in concrete as much as possible within the allowable burial depth. Otherwise, the catheter should be raised. After the leakage treatment is completed, waterproof plugs should be installed and re poured.
The main reason for pipeline water intake is insufficient irrigation concrete or high pipe opening elevation, which cannot reach the burial depth. Incorrect measurements caused the pipeline to rise to the outside of the concrete surface. The basic phenomenon is that the pipe is filled with water, and the water level in the hole drops significantly. There are three other methods to solve the suction problem of the catheter.
If the amount of grouting concrete is insufficient or the pipe opening is raised too high, causing water to enter the pipeline before it is buried deep, the pipeline can be used as a suction pipe. The concrete inside the hole can be sucked out using the empty pipe suction method and re poured.
The backfill method can solve the problem of water ingress caused by inaccurate measurement, that is, to backfill the pipeline with concrete, pump out the mud in the pipeline with a mud pump, and then pour the concrete. The prerequisite is that the surface concrete does not undergo initial setting. If the initial setting time is exceeded, it will be considered as a waste pile. If there is no burial depth, but there is a concrete surface inside the conduit and there is no water inside the conduit, it should be inserted and poured again, but it may cause interlayer, and attention should be paid to the test.
If the pipeline is not far from the pile top, it can be buried in the later excavation of the foundation pit, removing sediment and weak concrete layers, installing templates of the same diameter, and pouring concrete to the design elevation.
The reason why the conduit cannot be pulled out or pulled out is due to excessive burial depth, long initial setting time of concrete, excessive frictional resistance, and insufficient tightening torque of bolts. This fault can be solved by strengthening detection and controlling burial depth.
If the conduit breaks in concrete, it should be poured continuously and reinforced with steel bars; If the conduit breaks outside the concrete, the method of re insertion should be adopted on the premise of ensuring the quality of the concrete, setting waterproof plugs, and pouring the conduit again under heavy load. Initially not set up.
If the above methods are ineffective, the conduit should be pulled out in a timely manner, the poured concrete should be sucked out, the steel cage should be pulled out, the hole should be cleaned again, and the steel cage and concrete should be re placed. If it cannot be further processed, it can only be treated as a waste pile. The situation of abandoned piles must be avoided, which is inevitable, therefore the method of using cast-in-place piles must be adopted. Reinforced piles are divided into two types: original pile positions and abandoned pile positions.
The reverse circulation drilling rig can remove the drill cone, suction and discharge the mud and concrete slag with the mud pump, and clean the hole with clean water. The top surface of the original pile can be scraped off by welding a cross shaped steel frame on the drill bit, and then continue to pour the pipe, and strengthen the inspection in the future. The original pile position is scrapped. Generally, two symmetrical piles should be filled without any pile positions. The common method is to fill a pile on the original pile position and then pour another pile next to the pile position.
