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Sub-Classification System for Rocky Surrounding Rock of the Qingdao Metro
(Key Laboratory of Transportation Tunnel Engineering, Ministry of Education, School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031)
Abstract Based on the Qingdao metro project, a sub-classification system for rocky surrounding rock is studied, and elastic longitudinal wave velocities, core recovery percentages and forms of rock cores corresponding to various grades of rock masses are obtained. In light of the research results, a sub-classification system, which includes qualitative discrimination, elastic longitudinal wave velocity and rock core condition, is established. Applicability analysis of the sub-classification shows it has a good coincidence rate and the deviation of the rock mass grade is less than one sub-classification; the new classification system is favorable for reducing the span of design parameters for rock masses of different grades, which guarantees design safety and avoids waste. Uncertainty regarding rock mass classification decreases and the grading system for rocky surrounding rock is enriched.
Abstract：
Based on the Qingdao metro project, a sub-classification system for rocky surrounding rock is studied, and elastic longitudinal wave velocities, core recovery percentages and forms of rock cores corresponding to various grades of rock masses are obtained. In light of the research results, a sub-classification system, which includes qualitative discrimination, elastic longitudinal wave velocity and rock core condition, is established. Applicability analysis of the sub-classification shows it has a good coincidence rate and the deviation of the rock mass grade is less than one sub-classification; the new classification system is favorable for reducing the span of design parameters for rock masses of different grades, which guarantees design safety and avoids waste. Uncertainty regarding rock mass classification decreases and the grading system for rocky surrounding rock is enriched.
2018, Vol. 55 