| Boom-type road header is a part of tunnel boring machine suitable for soft rock tunnel construction,has the advantages of convenient construction,continuous excavation,blasting vibration,the small disturbance of surrounding rock and rock deformation delay occurrence,reducing over beaking,saving costandlining and it is conducive to control the merits of ground subsidence in subway construction.This paper takes Guiyang Rail Transit Line 1 as the engineering background,adaptability classification of Boom-type road header was studied,compared the construction of the Drilling and blasting method and the Boom-type roadheader is studied.and compared with field monitoring data,illustrate the advantages of Boom-type road header milling excavation method,has certain practical value for subway construction.The main work and research results are as follows:（1）Based on the situation of the site,the reasons for the construction of the Boom-type road header are summarized,the cutting theory and cutting mode of the Boom-type road header and the construction process of the Boom-type road header are analyzed.The construction characteristics and advantages and disadvantages of the Boom-type road header for the subway tunnel in the southwest rock stratum are analyzed and summarized,and the feasibility of construction of hard rock Boom-type road header for Guiyang metro tunnel is put forward.（2）Based on the two aspects of tunnel construction stability and construction efficiency,the factors affecting the adaptability classification of Boom-type road header are analyzed,and the uniaxial compressive strength,hardness and wear resistance of the rock,the development degree of the structure surface and the basic quality indexes are the basic indexes for the classification of the adaptable surrounding rock of Boom-type road header.The relationship between these indexes and working conditions of the Boom-type road header is analyzed,and the suitable range of the work of Boom-type road header is initially determined.（3）On the basis of the existing BQ classification and Q classification system,the concept of an adaptive surrounding rock classification BQmachineachine for Boom-type road header is set up in consideration of the factors of rock mass-mechanical interaction.Through the analysis of the relationship between the drilling rate,advance rate and the BQmachine,the appropriate factors are adopted to improve the adaptability of Boom-type road header.The adaptability classification method of Boom-type road header is put forward.Taking the Beijing road-Yanan road interval and the Train station-Shachong road interval project of Guiyang Rail Transit Line 1 as an example,the adaptability classification of Boom-type road header is tested and compared with the actual construction monthly footage,indicating the rationality and effectiveness of the adaptability classification of Boom-type road header.（4）Taking the Zhong-Ren interval tunnel project of Guiyang Rail Transit Line 1as an example,based on the proposed BQmachineachine classification method of the adaptable surrounding rock of Boom-type road header,the adaptability classification of Boom-type road header is studied in this section,which provides the theoretical support for the determination of the interval engineering scheme,and combined with the construction of the interval project.The numerical simulation method is used to analyze the influence characteristics of the construction of Drilling and blasting method and Boom-type road header.The changes of the displacement of the surrounding rock,stress and blasting vibration during the construction are analyzed.The site monitoring of the tracking construction further validates the superiority of the construction scheme for Boom-type road header of the Zhong-Ren interval tunnel project. |
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