- Excavate hard clay. Hard clay moisture content is low, cohesive force is large, the cutter rotation is clockwise, in the right transverse movement is easy to produce “hob” phenomenon, in addition to appropriate control of the left anchor mechanism dynamic pressure, but also to reduce the cutter speed, transverse speed, reduce the forward distance, and thin slice cutting.
- Excavation of sand. Sand is characterized by coarse particles easy to precipitate, in order to prevent the suction and discharge pipe blockage, excavation mud thickness and forward displacement should not be too large, the operation should be adjusted according to the vacuum gauge, pressure gauge. When the pipe is found to stop the horizontal movement, raise the cutter blowing water. If you stop the car or suddenly stop the car, you should dredge the pipe with clean water. When digging loose fine and silty sand, the cutter can be used at a low speed, or according to the suction distance of the suction mouth and the thickness of the sand layer, the suction operation method can be fixed point.
- When excavating plasticity or hard plastic clay, the soil is easy to be embedded between the blades and stick, so that the cutter speed decreases or even loses its function, so every once in a while, the cutter should be lifted out of the water for inspection (the suction is still kept under the water), timely remove the blockage.
- The best mud concentration (8%-25%) can be used to control the vacuum gauge and pressure gauge when excavating silt and quicksand. If the mud layer thin can increase the forward distance and transverse velocity, but also can not cutter or use fixed point, fixed suction method.
- Control the width and speed of the transverse movement. Cutter suction dredger in the transverse process of the transverse width and transverse speed and reasonable control is very important, it can not only control the slurry concentration, but also improve production efficiency, and can make the trench level, improve the quality of construction, it is mainly based on the construction area soil, the change of the vacuum gauge and pressure gauge, wind pressure and flow pressure on the influence of transverse speed, in combination with dredging depth and thickness of mud on the premise of guarantee the project quality, or try to dig by calculation the optimum horizontal digging width and transverse speed, in order to get the best slurry concentration (generally cutter suction dredger maximum digging ship the total length of 1.2 times the width or swinging Angle it is advisable to about 80%).
- Correct control of slurry concentration. The slurry concentration control of cutter suction dredger refers to the regulation and control under certain dredge pump performance and construction conditions. On the basis of knowing the characteristic curve of the dredge pump and discharge pipeline and mastering the main factors affecting slurry concentration, how to adjust and control the vacuum gauge, pressure gauge, and ammeter reading correctly and timely to adjust slurry concentration is of great significance to improve production efficiency. Under the given dredge pump power condition, if the pipeline is short, the mud is light and there is the residual head, the slurry velocity still has the ability to carry sand, then the slurry concentration can be appropriately increased to increase the production efficiency. On the contrary, if the mud pipeline is long and curved, the mud is heavy, and the mud content in the mud reaches the saturation state, then the slurry concentration cannot be increased. At this time, the pressure gauge should be paid close attention to the change. For example, under the conditions of standard discharge distance and depth of 1000m^3/h cutter suction dredger, the suction vacuum shall be controlled to be between 350-450mmhg when digging heavy soil, and the optimal slurry concentration when digging loose soft soil shall be controlled to be between 450-550mmhg. If the slurry is very thin, it is necessary to accelerate the transverse velocity and increase the forward displacement to obtain the optimal slurry concentration. In actual operation, the control of slurry concentration is generally reflected by vacuum gauge and pressure gauge, so before construction, according to construction conditions, through calculation (or test excavation) to the best slurry concentration to control the vacuum, pressure, current to operate. When the reading of the vacuum gauge and pressure gauge is stable in a high-value range and there is no blockage, the concentration is higher and the production efficiency is better; If the vacuum rises sharply, the reading of the pressure gauge decreases, indicating that the suction is blocked or there is a garbage stop; Vacuum decline that inhaled concentration is low, such as a sharp rise in the pressure gauge reading, vacuum gauge readings to drop, then dredge pipe blockage or slurry concentration is too high will incline to block the pipe, the concentration shall be reduced or improve the suction water absorption when it is necessary to increase the host speed water will dredge pipe blowing, decreased when the pressure gauge reading instructions concentrations decrease; When the reading of suction vacuum and a pressure gauge is lower than that of normal mud suction and mud conveying, the dredge pump is blocked. In conclusion, during the dredging operation, operators must pay close attention to the changes of vacuum, pressure, and current, and adjust the transverse velocity, the forward displacement, and the thickness of the dredging layer at any time under the given construction conditions to make the suction vacuum and discharge pressure. Reflecting normal and stable within the approved range ensures that the slurry is at an optimal concentration line (not the highest concentration) for optimal production efficiency.
- Increase the input of science and technology to realize the computerization of dredging operation. Carry out technical innovation in the control room, install the monitoring system for the dredging operation of the cutter and GPS locator, so that the operation of the cutter can be controlled, and operate the dredging according to the designed trench size to improve the engineering quality and dredging efficiency.
