Research On The Adaptability Of TBM Cutter To Rock Joints

With the rapid development of economy in China,the constructions of urban underground transportation engineering,municipal pipeline,railway tunnel and other tunnels are increasing.In order to meet the urgent need of the tunnel construction,the full face rock tunnel boring machine(TBM)has been widely applied for its technology and economic advantages.China has a vast territory,a wide variety of rock and soil,and the complexity of the geological conditions have a higher requirements for the efficiency of cutter breaking.Therefore,a large number of engineering practice show that it is important to adjust the optimal operating speed of the TBM according to different geological conditions,which is helpful for improving the rock breaking efficiency.The joints in rock are tiny cracks in the rock,which have a certain influence on the expansion of rock crack,so as to affect the efficiency of rock breaking.At the same time,the effect of the rock on the cutter makes the cutter produce some wear,which affects the life of the cutter,and influences the efficiency of the construction and the time and the cost on the underground engineering indirectly.Therefore,in this thesis,the rock breaking process with different joint angles and joint space was simulated by setting up the model of disc cutter breaking rock,and the influence of joint angles and joint space on the efficiency of rock breaking was analyzed.Secondly,in the process of TBM,the running speed of the cutter is directly related to the rotation of the cutter head and the forward speed.Finally,through the experiment we further verified the simulation results,the relationship between the load rate of the cutter and the breaking rock,the shape of the rock and the internal structure of the rock were studied.The main work of this thesis was as follows:(1)The research status and application of TBM technology was Introduced,and the failure of disc cutter for TBM was analyzed.(2)The mechanism of the cutter breaking rock was analyzed,and provide a theoretical basis for the analysis of the broken rock was established.(3)The influence of rock joint characteristics on the rock breaking was studied.By setting up the model of disc cutter breaking rock,the rock breaking process with different joint angles and joint space was simulated,and the influence of joint angles and joint space on the efficiency of rock breaking was analyzed.The above research show that the plastic strain in the rock breaking process of the cutter was extended to the rock.At the condition of the joint spacing was the same,the rock breaking efficiency was the highest when the joint angle was 60 degree;while the rock breaking efficiency was the lowest when the joint angle was 90 degree.Secondly,the research results show that the amount of rock breaking was smaller with the increase of joint spacing.When the rock joints spacing was larger than the range of 100mm,the influence of joint spacing on the rock breaking was small.(4)The influence of the cutter's speed on the rock breaking was studied.By setting up the model of the cutter's speed on the rock breaking,the influence of the cutter's rotation speed and penetration speed on the rock breaking were analyzed.The above research results show that the cutter rotating speed for the joint effects of rock fragmentation has no regularity;and the penetration rate of the cutter to crushing rock has certain regularity.Under the same rate of penetration,when the joint angle was 60 degree,the rocks were most easily broken.(5)The experiment had researched on the broken process of the granite,through the comparison between the experimental data with the theoretical data to verify the correct of the simulation results,which is also helpful for selecting the best parameters of the cutter,and providing a reliable reference for the efficient operation of TBM.In summary,the main work of the thesis was focused on studying the adaptability of TBM cutter to rock joints.From the present practical problem,the relevant mathematical model was set up,and the influence factors of TBM cutter in the process of the rock breaking in simulation and experiment was researched.