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Study On Quality Variation And Control Method Of Tunnel Excavation In Highway Tunnel In Qin-Ba Mountains Area Under Complex Geological Conditions

Posted on:2020-07-29Degree:MasterType:Thesis
Country:ChinaCandidate:K KangFull Text:PDF
GTID:2392330572986637Subject:Engineering
Abstract/Summary:PDF Full Text Request
Qin-Ba Mountains Area is an important industrial and national defense base in China,and it is also a must for several highways in the country.Due to the complicated geological structure of Qin-Ba Mountains Area,the construction of highway tunnels in the Qin-Ba Mountains Area has higher requirements on the quality control level of the tunnel,especially in the quality level of the tunnel excavation.Based on the typical Qinba Mountain tunnel-Chengkai Tunnel,this paper systematically studies the quality variation and control method of tunnel tunnel excavation by combining theoretical analysis,engineering investigation and numerical simulation.Firstly,based on the geographical environment of Qin-Ba Mountains Area and combined with the technical data of survey and design,we analyzed and summarized the complex geological features of Qin-Ba Mountains Area and the inevitable difficulties encountered in tunnel excavation,and introduced the Chengkai Tunnel Project features.Secondly,we established an indicator system and indicator evaluation mechanism for quality variability evaluation of tunnel excavation.The indicator system include two major categories: over-under-excavation indicator system and profile neat indicator system,subdivided into six key indicators: average linear over-excavation,maximum linear over-excavation,maximum linear under-excavation,peripheral eye mark preservation rate,blasthole utilization,and maximum size of two stubble artillery connection.Guided by relevant norms,the variability analysis and process quality assurance capability analysis of the stage measurement results of each indicator were respectively carried out.The analysis results show that the process quality assurance capability of the tunnel excavation was low,and the over-under-excavation indicator system was the main indicator for the quality variation of the tunnel excavation,and the control target was proposed accordingly.Thirdly,by establishing the hierarchical structure model of influencing factors of the over-under-excavation,we obtained the sequencing of main factors affecting the variability about the drilling precision and blasting technical parameters,and the quality assurance plan for ensuring drilling accuracy and blasting technical parameters was determined,and verified in actual excavation.By establishing the over-under-excavation prediction model of BP neural network,and according to the orthogonal design principle,the selected 9 sets of blasting technical parameters were predicted,and a further quality improvement plan of the blasting technical parameters was obtained.On this basis,we proposed the continuous optimization and adjustment plan of excavation quality under complex geological conditions.Finally,we established the comprehensive integration weighting method evaluation model,and made a comprehensive evaluation on the effect of the quality improvement plan applied to the Chengkai Tunnel.The evaluation results showed that the quality assurance ability was improved obviously,and the quality target was achieved well,which verified the feasibility of the quality improvement plan for the tunnel excavation,and guaranteed the objectivity and accuracy of the evaluation results.
Keywords/Search Tags:Qin-Ba Mountains, Tunnel Excavation, Quality Control, Blasting Technology
PDF Full Text Request
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