| Miner mining is the main mode of operation in coal mining.However,the coal mine operation construction conditions are poor,once the collapse accident,will cause a large number of casualties.Taking scientific,reasonable and timely rescue measures is the key to rescue work.Therefore,it is urgent need to develop a safe fast and right for complex environment drilling technology and equipment.The pipe jacking construction method can be suitable for rescue work under the environment of large cross-section underground.Cutters and disc cutters are commonly used cutting tools.The mechanism of crushing coal rock and the setting of related cutting parameters help to improve the efficiency of crushing coal rock,which will also affect the design of the cutterhead.Therefore,this article has carried out research on the mechanism of commonly used rock-breaking tools to break coal rock,the influence of different cutting parameters on rock-breaking performance and design of cutterhead,which provide a certain foundation for my country's independent research and development of cutting tools,optimization of cutting tool structure,and application in practical engineering.And reference,at the same time,it can also provide a theoretical basis for rapid and safe tunneling of pipe jacking construction.The major research work are as follows:(1)Based on the material properties of coal rock and the structural characteristics of the cutter,a finite element analysis model of the cutter cutting coal rock is established,the cutting process of the cutter breaking coal rock is simulated,and the principle of coal rock crushing under the action of the cutter is analyzed.And the influence law of cutting force change,the change law of cutting force under different cutting rake angles and different cutting depths of the cutter is studied.(2)The rock breaking theory and failure criteria of the hob are summarized.According to the Drucker-Prager plasticity criterion and related mechanics,a finite element analysis model for rock breaking by a single hob is established,and the finite element analysis model for rock breaking by a hob is simulated.In the rock breaking process,the stress cloud diagram at different moments and the change law of the three-dimensional force of the hob are analyzed,and the influence of the penetration of the coal rock with a single hob and the cutting speed on the cutting force is analyzed.(3)Based on the Drucker-Prager model to describe the plastic constitutive relationship of coal rock,the failure process of coal rock deformation,fragmentation and peeling under the action of dual hobs was simulated under the conditions of simultaneous cutting and sequential cutting with dual hobs.The influence of tool spacing on cutting force,rock fragmentation and specific energy is analyzed,and finally the differences between the two cutting methods are compared.(4)The cutterhead structure design is carried out for the mine pipe jacking machine,including the selection of the cutterhead,the position of the cutterhead support beam,the opening rate of the cutterhead,etc.,and a three-dimensional solid model of the cutterhead is created.The finite element simulation analysis was carried out for four different working conditions,which verified the rationality of the cutterhead design.Finally,a crushed rock yard in Guangdong was selected as the experimental base to conduct field experiments.Through the research of this subject,the mechanism of the cutting tools cutting coal rock and the influence of different cutting parameters on the rock breaking effect and breaking forces are obtained;the structure the cutterhead of the mine pipe jacking machine are designed.Obtained cutterhead deformation diagrams and stress cloud diagrams under different working conditions,which provide a certain foundation and thinking for optimizing the structure of the cutter,cutterhead design and tunneling parameters,and also provide a theoretical basis for rapid and safe tunneling of pipe jacking construction. |
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