| With the rapid development of economy in our country,the tunnel engineering construction of railway tunnels,municipal pipelines and underground traffic is growing.The full face rock tunnel boring machine(TBM)has been widely recognized and used in order to meet the urgent needs of the tunnel construction.It has become the mainstream equipment with the characteristics of high efficiency,safety and environmental protection.On the construction projects in future,the application proportion of TBM will increase.Disc cutter are key components because it directly contacts with the rock in the excavation process.The rock-breaking efficiency relates to the construction progress and economic benefits.Therefore,the study about disc cutter of breaking rock is very important and has practical significance.This thesis summarized the stress model of disc cutter and theory of fractured rock,analyzed the cutting mechanism and constitutive model of rock.The relationship between the cutter spacing and penetration,cutter radius,rock characteristics by CSM comprehensive prediction model was drawed.The optimal cutter spacing mechanical model of double disc cutter was founded.A series of rock-breaking models using the finite element analysis software was established.The models simulated single disc cutter point pressure of rock dynamic process.The Mises stress nephogram and stress of the rock change curve was got.The existing pressure testing machine was designed to be suitable for the rock-breaking experiment,and rock crushing conditions was explored.Linear cutting model of double disc cutter was established to analyze the distribution and broken of rock stress and strain in different condition for exploring the impact on cutting rock.Combined with the actual working condition,3D rotation rock damage simulation of double cutter was established to analyse the rock-breaking effect on cutter space and phase angle.Research results have a certain reference value to understand cutting mechanism and optimize disc cutter cutter.Thesis research results showed in the simulation of point pressure cutting,the rock area contacting with the disc cutter had the biggest stress values and happened deformed.With continuous loading of disc cutter,rock stress transfered from the contacting area to rock internal area.It had energy consumption in the whole process.There was the same stress value trends in different places.Vertically,the stress value increase with the distance increase of the contact area,and there was a time delay in stress value change.Horizontally,there was no time delay in stress value change,just stress amplitude decreaseed.In the experiment of disc cutter cutting sesame gray and giallo cecilia,rock happened brittle failure and cracks throughout the whole rock mass.The maximum diameter of rock fragments is primarily less than 5 mm.With the increase of loading rate,the crushing force of sesame gray increasing slowly,while the crushing force of giallo cecilia increasing sharply.3D scanner was used to detect fracture face.The fracture surface was found had some concave and convex.There was some cracks existed below the cutter contact region.Sesame gray crack was oblique line while giallo cecilia crack volatility and irregular.In disc cutter linear cutting simulation,the optimal cutter spacing was 80mm for the cutter sequentially loading and loading,but the rock breaking effect of sequentially loading was better than the loading.Granite failure units of cutter space in the 0-500mm increased with the cutter space bigger.In disc cutter rotation cutting simulation,the rock failure unit variation was linear and stable when the distance of the cutter installation position and the center of cutterhead was more than 500 mm.In the penetration of 5 mm and cutting wheel revolving speed of 6.28 rad/s,the optimal cutter spacing was 120mm,the optimal phase angle on sequentially rotation determined 120°. |
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