Study on the Scouring Characteristics of Large Diameter Slurry Shield with Normal Pressure Cutter Barrel
When the slurry shield crosses the clay and mudstone strata,the clay residue is easy to block the cutter barrel,causing the hob rotation to be obstructed and the deflection wear to be serious,which greatly reduces the tool life and limits the tunneling efficiency of shield machine and brings large economic loss.In order to solve the blockage problem,this paper used CFD method to establish the solid-liquid two-phase flow model of cutter barrel scouring,simulated the process of scouring line in the cutter barrel to remove the slag,analyzed the influence law of nozzle inlet pressure on scouring efficiency,and finally proposed that the nozzle inlet pressure should be kept above 9 bar.The nozzle arrangement parameters were further optimized,and the nozzle arrangement parameters and the remaining residue volume fraction λ were used as the input and output of the BP neural network respectively for training,and the predicted values were used as the adaptation degree,and the optimal arrangement parameters were solved by genetic algorithm.The results show that the optimal flushing effect can be achieved with the arrangement parameters of Distance=142 mm,Angle=165°,and Depth=35 mm;the value of λ decreases from 44.43%to 8.89%after 20 s of flushing using the optimized arrangement parameters for simulation,and the scouring effect is significantly enhanced.
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