Research Of Crushing Performance On Rock Breaking With High Pressure Water Jet Coupled With Disc Cutter

TBM are widely used in underground projects such as subways,water conservancy,mines,and river tunnels.However,due to the complex and changing geological conditions,TBM encounter more and more geological conditions of extremely hard rocks during tunneling.Under such stratigraphic conditions,TBM are highly susceptible to problems such as difficult rock breaking by disc cutter,severe tool wear,and low tunneling efficiency.For this situation,this paper uses a combination of theoretical analysis,numerical simulation and experimental research to study the rock breaking performance under different coupled rock breaking parameters of high-pressure water jets and disc cutter,and the main contents of the paper are as follows:(1)Based on the computational fluid dynamics method,the pressure and velocity fields of the water jet flow field of three different nozzle structures were numerically simulated and analyzed to compare the effects of the three nozzle structures on the jet velocity and pressure.The results show that the performance of the tapered straight nozzle is better than that of the tapered nozzle and the flat nozzle,whether it is the axial velocity of the jet,the velocity of the jet section or the total pressure of the jet.(2)By using the finite element and smooth particle hydrodynamics coupling method to establish a numerical model of rock fragmentation process of coupled high-pressure water jet and disc cutter,the damage process of rock body under the synergistic action of high-pressure water jet and disc cutter was studied,and the influence law of three working parameters,namely,different high-pressure water jet and disc cutter spacing,water jet impact velocity and disc cutter penetration degree,on rock body fragmentation was analyzed.The results show that when the water jet velocity is greater than the critical value of 200m/s,the reduction is significantly reduced;at the same time,the coupled rock-breaking ratio energy consumption reaches the lowest value under the hob penetration degree of 6mm,50 mm water jet and hob spacing,200m/s water jet velocity,and the rock-breaking efficiency is the highest at this time.(3)Using disc cutter linear cutting experiment platform equipped with a high-pressure water system,the disc cutter breaking process and rock crack sprouting and expansion were analyzed,and then experiments of high-pressure water jet and disc cutter breaking of different kinds of rocks were carried out,and experiments were conducted at different spacing and disc cutter penetration degrees to analyze the change law of the effect of different parameters on rock breaking efficiency.The results show that when the water jet is coupled with the disc cutter to break the lower strength rock compared with the high strength rock,the spacing between the water jet and the disc cutter can be increased appropriately according to the penetration degree in order to make the rock be stripped and broken more efficiently.Compared with disc cutter,the coupling of high-pressure water jet and disc cutter can effectively reduce the rock breaking load of disc cutter;and the optimal spacing between water jet and disc cutter for different penetration is obtained to verify the correctness of numerical simulation.