Analysis Of The Working Behavior Of TBM Hobs

With the continuous enhancement of comprehensive national strength,China has developed rapidly in the field of railway and highway construction,and is building a transportation network with wide coverage and high efficiency,in order to realize people's choice and rapid travel,and to facilitate the lives of the masses.The full-section rock tunnel boring machine is an advanced large-scale mechanical equipment for excavation of underground rock layers such as tunnels.Compared with traditional blasting drilling operations,it has a friendly construction environment,high construction efficiency,good safety and long-distance tunnel construction economics.Significantly a series of advantages,widely used in the construction of railways,highways,water conservancy projects,etc.Therefore,TBM has broad market application prospects,and the construction party has put forward higher requirements for the tunneling performance of TBM.The TBM mainly uses a hob mounted on the cutterhead panel to roll the rock face of the face to break the rock and complete the tunnel opening work.Rock is a basic component of rock mass.It is a brittle material with complex structure.The main characteristic is non-uniformity.The hob is the core component of rock breaking in direct contact with rock.Its installation,force characteristics and wear characteristics.All of them indirectly affect the efficiency of TBM tunneling.Therefore,this article has consulted a large number of relevant literatures,based on the development status of TBM excavation technology and TBM hob research at home and abroad,completed the following points:(1)Based on ABAQUS finite element simulation,the numerical simulation of rock breaking characteristics of six disc hobs with different installation radii on a certain type of TBM cutterhead was carried out.The stress-strain response characteristics of the rock-breaking rock of the hob and the hob contact stress were analyzed,hob rock breaking resistance and rock breaking friction work.It is found that the faster the hob radius of the installation radius,the better the work,the more the rock breaking amount,the lower the overall friction loss;the closer the rock stress is from the lower edge of the hob blade,the rock stress at the same position below the blade edge.It is basically not affected by the mounting radius of the hob;the contact stress and rock breaking resistance of the hob are in constant fluctuation,and the breaking force of the hob is not increased due to the increase of the installation radius.(2)The influence of rock confining pressure,excavation stratum,penetration degree,blade width,cutting edge angle and knife spacing on the rock breaking force of the hob was analyzed by single factor variable method.The stratum factors have the most significant influence on the crushing force of the hob.The higher the rock strength of the excavation stratum,the harder it is.The greater the rock breaking resistance is,the worse the machinability is.The change of various factors does not change the volatility,step and synchronism of the breaking force of the hob,and only changes its step value.The orthogonal test is carried out on the factors affecting the rock breaking force of the hob.The analysis shows that the structural parameters of the disc hob(the flat blade disc hob with small width and blade angle change)and the influence of working parameters on the rock breaking force are:penetration>blade width>knife spacing>blade angle.(3)Based on the two factors of the hob wear mechanism and the influence of the hob wear,the arc length and wear rate of the disc hob are studied.The formation parameters are the main cause of the large wear of the hob.The penetration degree has a great influence on the length of the rock breaking arc of the hob,and the length of the broken rock of the hob increases with the increase of the penetration degree.The blade width,penetration and cutter speed have the most significant effect on the hob wear rate.The cutter radius,mounting radius and knife spacing have a relatively low effect on the hob wear rate.The rock-breaking simulation test of the disc hob with different wear and tear of normal wear is carried out to study the rock-breaking characteristics after wear.It is found that the hob after the running-in has higher rock breaking efficiency and is beneficial to rock breaking.