Experimental study on memory cutting of roadway cross section containing gangue based on infrared thermography

During the drivage of coal roadway cross section containing gangue,the gangue cutting will cause sudden cutting load change,leading to severe wear of pick and violent vibration of body part,thus it increases the failure rate and reduces the service life of the boom type roadheader.To ensure the cutting stability of the cross section with gangue and improve the service reliability of heading equipment,the strategy of “infrared thermography+memory cutting” was put forward.Considering the characteristic of pick wear,the closed cutting heat system of pick without wear and with wear were analyzed.The mathematical model between cutting heat generation and coal rock strength was established to prove the rationality of using the discontinuous cutting temperature increase to represent the coal rock strength.Rock samples with different mass ratios were performed by swing cutting,and the cutting infrared thermography and temperature signal were obtained.Combining the cutting temperature signal in the stable stage,the change law of cutting temperature under different properties was analyzed to verify the feasibility of identifying the gangue based on cutting temperature increase.Taking the infrared thermography and cutting temperature obtained in the previous round of cutting as the basis and the avoidance of large gangue as the target,the memory cutting process of the cross section containing gangue based on the infrared thermography was studied on the cutting platform of roadheader.The results show that compared with the non worn pick,the total heat generated with the worn pick consists of the heat generated by the compression and shearing of coal rock by the pick,the heat generated by the friction between the coal rock and the rake face of pick,and the heat generated by the friction between the coal rock and the flank surface of pick,which has a positive correlation with the strength of coal rock.With the increase of rock sample strength,the average cutting temperature,the maximum cutting temperature and the average cutting temperature amplitude all show an increasing trend,which proves the feasibility of using infrared thermography to identify the gangue in roadway section.When cutting the gangue,the characteristics of the infrared thermography and the cutting temperature change significantly.The memory cutting strategy based on the infrared thermography can reduce the maximum cutting heat by 60%,the maximum vibration acceleration by 90% and can effectively improve the cutting stability of cross section containing the gangue.