| Full-face rock tunnel boring machine(TBM)method has the advantages of high operation efficiency,good safety and environmental protection.With the rapid development of TBM manufacturing technology and construction level in China and abroad,it has gradually become the main method for long-distance tunnel construction in China and abroad.Due to the poor adaptability of TBM to unfavorable geology,the classification of tunnel surrounding rock is an important reference material in TBM tunnel construction.The surrounding rock classification method used in the current specification is based on the stability of surrounding rock,which is suitable for traditional construction methods such as drilling and blasting method.Therefore,it cannot effectively guide TBM selection,tunnel support,arrangement of construction schedule and cost budgeting.It is urgent to explore and study the surrounding rock classification method suitable for TBM tunneling.According to the existing surrounding rock classification system of HC method,considering two important factors that affect the boreability of surrounding rock and unfavorable geological conditions of TBM tunnel construction,based on the Hanjiang-to-Weihe River Diversion Project,a TBM adaptive surrounding rock classification method is explored based on the scoring method.The correlation between the total score of surrounding rock and the performance parameters of TBM tunneling is studied,and the prediction model of TBM tunnel construction performance is proposed.The correlation law between different surrounding rock quality and tunneling parameters is revealed,and the prediction of TBM tunneling performance parameters is realized.(1)The influence of hardness and abrasiveness of surrounding rock on the boreability of surrounding rock is studied,and the boreability indexes are classified.The key unfavorable geological conditions affecting TBM tunneling are classified,and the unfavorable geological factors of different grades are scored.The quantitative analysis of unfavorable geological conditions is realized.Considering the influence of surrounding rock excavation and unfavorable geological conditions on TBM tunneling,the classification standard of surrounding rock suitable for TBM tunneling is established.Compared with HC method,this classification is more safe and in line with the actual situation of the construction site.At the same time,three kinds of information can be obtained,including the classification and the boreability of surrounding rock,and the unfavorable geological conditions.(2)According to the proposed classification method of surrounding rock of TBM tunnel for Hanjiang-to-Weihe River Diversion Project,it is applied to the Yinsong project and the TBM construction prediction model database is established.According to the correlation analysis between the total score of surrounding rock and the TBM performance parameters,the empirical formulas of the total score of surrounding rock(R)and the rate of penetration(PR),cutter penetration(p),utilization coefficient(UI),field penetration index(FPI)and torque penetration index(TPI)are obtained.On this basis,the TBM tunnel construction prediction model is established.(3)According to the periodic variation of tunneling parameters in the circulation section,the circulation section is divided by the cutter head speed as the criterion.The fast Fourier transform(FFT)method and the data screening algorithm are used to denoise and filter the abnormal and high-frequency values in the measured data of TBM,which provides the data basis for the application and evaluation of TBM tunnel construction prediction model.The relationship between the driving parameters and the surrounding rock types and the change rule along the stake number are analyzed,which provides a reference for evaluating the construction efficiency of TBM and surrounding rock conditions.(4)The classification of TBM surrounding rock is carried out by selecting the continuous tunnel sections in the Hanjiang-to-Weihe River Diversion Project and the Songhua River Diversion Project.Based on the tunneling construction prediction model,the key parameters to guide the TBM tunneling construction are predicted,and the accuracy and stability of the proposed model are verified by comparing with the measured data and error analysis,which provides a theoretical basis for the classification of TBM tunnel construction performance. |
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