Study On Tbm Hob Wear And Rock Breaking Efficiency Based On Rock Slag Particle Size Distribution

Compared with the traditional drilling and blasting method,TBM tunnel construction has become the best choice for long tunnel construction due to its advantages such as fast construction speed,low economic cost,safe construction operation and less impact on the surrounding environment.How to improve the rock breaking efficiency and reduce hob wear under the premise of ensuring construction safety is a hot topic in TBM construction field.In view of the complexity of geological conditions and the randomness of the construction process,how to reasonably predict and evaluate the rock breaking efficiency and hob wear of TBM is a difficult problem to be solved in the field of TBM construction.Although researchers have conducted extensive and in-depth studies on rock breaking efficiency and hob wear of TBM,there are few studies on rock breaking efficiency and hob wear based on the grain size distribution of rock slag,which need to be further improved.Based on this,this paper supported by the National Natural Science Foundation of China(No.41972270)"Evaluation and prediction of TBM tunneling efficiency based on multi-source information feedback mechanism" and the open project of the State Key Laboratory "Evaluation and prediction of TBM tunneling efficiency and tool abrasion based on information fusion feedback mechanism".Taking the water transport tunnel of Lanzhou water source construction project as the engineering background,and taking hob wear and rock-breaking efficiency as the research object,this paper designs a scale hob wear test for soft and hard composite rock mass,comprehensively utilizes the data of rock slag information,tunneling parameters,hob wear and energy consumption in tunneling,and adopts theoretical deduction,mathematical statistics and other methods.Taking the construction of TBM tunnelling efficiency and optimization of TBM tunnelling parameters as the overall research objectives,a systematic and in-depth study on hob wear and rock breaking efficiency was carried out based on the grain size distribution of rock slag,and the engineering examples were compared with laboratory test results.The research results can provide scientific guidance and basic support for TBM tunnel construction prediction,tunneling parameter optimization,tool life management and economic benefit evaluation.The main research contents and conclusions are as follows:(1)design the hard and soft rock mass scale hob broken rock and abrasion test,poor analysis,variance analysis,the organic combination of a variety of means such as factor effect analysis,study hard and soft composite rock mass scale hob abrasion law,the results showed that the quality of hob wear and lithology,penetration and cutter spacing of correlation analysis with three factors respectively,the results show that the lithology of hob impact factors,the largest granite the optimum S/P less than optimum S/P of sandstone.(2)The rock slag from the reduction scale hob abrasion test was screened,and the screening mass under different tool spacing was analyzed.The conclusion was drawn that in order to improve the rock breaking efficiency,it is still necessary to reasonably select the tool spacing and penetration degree to produce more and larger rock slag.The cumulative probability method and theoretical function fitting were used to calculate and summarize the grain size distribution indexes of rock slag.The results show that the Rosin-Rammler function has the best fitting relationship with the grain size distribution of rock slag.(3)Considering the roughness index,non-uniformity coefficient,curvature coefficient,geometric mean particle size and R-R function mean particle size,the correlation analysis method was adopted to establish an effective relationship between hob wear and particle size distribution law of rock slag.(4)Taking the broken specific work as the dependent variable and using the linear regression analysis method,the fitting models of the broken specific work and the new surface theory,the similarity theory and the crack theory were established respectively.The conclusion was drawn that the prediction model of rock breaking efficiency based on the new surface theory was the most consistent.Said theory analyzes the new surface index f relations with strength,abrasion resistance,discusses the f changing with the tunneling of the thrust,the results show that the rock strength is higher,the stronger the wearability,f,the greater the rock fragmentation efficiency is lower,but constantly increasing thrust will not increase the efficiency of rock fragmentation,continue to increase the thrust reaches the critical value,rock fragmentation efficiency lower.(5)combined with lanzhou water conveyance tunnel project example,the validation is based on the analysis of the particle size distribution of rock slag slag method is reasonable,and compared with laboratory test results,the results show that the slag is secondary wear and transport wear,the field data of roughness index is lower than that of the indoor test 30 or so,at the same time,using the theory of new surface index f in the evaluation of rock fragmentation efficiency in practical engineering is feasible,but needs to be discussed in different surrounding rock conditions analysis,optimization of excavation parameters.