Experimental investigation on the influence of tunneling parameters on the test results of new soil abrasion testing method
摘要
Excessive tool wear in abrasive ground has become a critical factor restricting tunneling efficiency. To evaluate soil abrasion and tool wear, a series of testing methods have been proposed. However, the lack of comprehensive analysis on the soil-tool tribology system prevents them from accurately reflecting the contact conditions between tunnel face and cutting tool. Moreover, the tunneling parameters are determined subjectively by designers, potentially skewing test results. In the present study, the deficiencies of existing test methods have been analyzed, and the WHU-SAT test method has been developed. Compared with existing test methods, the rational design of cutterhead structure and cutter geometry enables a more realistic simulation of cutting process and wear mechanism. The high-precision monitor system promotes a more rigorous test process. The influence of tunneling parameters on scraper wear has been studied for parameter determination to avoid inappropriate parameters interfering with test reliability. The results indicate that scraper wear increases first and then stable with increasing rotation speed, with a recommended value of N = 100–200 r/min. With increasing tunneling speed in nature sand (or quartz sand), scraper wear decreases (or increases) first and then stable, with a recommended value of V = 10–30 mm/min. As the increase of cutterhead penetration depth, scraper wear increases slowly and then rapidly, with a recommended value of h = 120–150 mm. Since sand particles are crushed during the cutting process, the increase rate of scraper wear decreases with increasing test time. Considering the constraints between weighing error and test efficiency, the recommended value is t = 60–90 min.