Research On Rock Breaking Efficiency Of Water Jet Based On Mechanical-hydraulic Combined TBM

The full-face tunnel boring machine(Tunnel Boring Machine,TBM)is currently internationally recognized.Compared with the traditional methods,the new tunnel excavation method has great advantages in terms of construction schedule and construction technology.The surrounding rock disturbance is small,and the quality of the hole is high.However,with the advent of the development era of tunnels and underground space,TBM is also facing huge challenges.The increase in rock strength reduces the construction progress of TBM.Therefore,on this basis,based on the mechanical-hydraulic combined rock breaking model,this article uses a domestic CNC ultra-high pressure water cutting machine to conduct cutting experiments on rocks of different strengths to study how to improve the cutting ability of water jets on rocks of different strengths to improve TBM The efficiency of excavation.The research content mainly includes the following aspects:(1)First,through experiments to study rocks of different strengths,under the influence of different water jet parameters such as jet pressure,cutting speed,target distance,etc.,a summary and analysis of the laws affecting the depth of cutting rocks are carried out.The law shows that when the rock strength is low,the ability of the water jet to cut the rock can be improved by increasing the jet pressure,reducing the cutting speed,and reducing the target distance.However,if the rock strength reaches a certain level,the water jet’s impact on the rock can be improved.Cutting capacity will be reduced,and increasing jet pressure,reducing cutting speed,and reducing target distance cannot significantly increase the maximum cutting depth of water jet cutting rocks.At this time,it is necessary to study new ways to increase the maximum depth of water jet cutting rocks.method.At the same time,after the cutting is completed,the width of the slit and the temperature of the rock are also related to the water jet parameters.The larger the jet pressure and target distance,the smaller the cutting speed and the larger the slit width;the greater the jet pressure,the smaller the cutting speed and target distance.,The higher the temperature.(2)In response to the above-mentioned experiment,when the rock strength reaches a certain level,the water jet cutting ability is insufficient,and considering the actual situation of TBM,the method of repeatedly cutting the same slit is proposed to improve the water jet cutting ability,and design The corresponding device.At the same time,for the problem of high temperature after the water jet cutting is completed,the method of using ice particles instead of high-pressure water to break the rock,and designing the corresponding device,achieves the purpose of reducing the temperature of the working surface and extending the residence time of the workers on the working surface.Improve the efficiency of TBM rock breaking.(3)Finally,the method of repeatedly cutting the same slit is verified through experiments.The results of verification show that this method can indeed effectively increase the ability of water jet to cut rocks,and the more repeated cutting times,the greater the jet pressure and the higher the cutting speed.Slow,the smaller the target distance,the greater the depth of repeated cutting,and the greater the maximum cutting depth,but the depth of each repeated cutting is not the same,and as the number of repeated cutting increases,the depth of each increase is Gradually decreasing.It was also found that as the number of cuts increased,the cutting width was also increasing,and the jet pressure and the target distance were proportional to the width,and the cutting speed was inversely proportional to the width.This conclusion will be beneficial to the improvement of TBM equipment,and also has important reference value for the development of TBM equipment in the future.