摘要
Abstract
Based on the conventional surrounding rock classification method,this study introduced the karst development degree correction coefficient(CKD),and comprehensively modified the basic quality index(KBQ)of surrounding rock through quantitative and qualitative indicators,and proposed a surrounding rock classification method suitable for karst areas.Taking the drainage tunnel project in a karst collapse area in Sichuan Province as an example,combined with the classification of surrounding rock in different mileage,a differentiated support scheme was formulated.The results show that the lower the grade of the surrounding rock(such as grade IV),the greater the settlement and the slower the growth rate,and the poor geological conditions directly weaken the self-stability of the surrounding rock.The peripheral convergence displacement is significantly higher than that of the vault settlement,and the deformation is violent in the initial stage and tends to be stable in the later stage.The axial force of the bolt showed a trend of increasing first and then stabilizing,and the force of the arch bolt was the largest,and the side wall was the smallest.The distribution of stratum settlement is V-shaped,and the settlement near the center of the karst cave is the largest,and the surface influence range is wide,and the settlement decreases with the increase of depth.The modified classification method can accurately reflect the geological influence of karst,and the support design can effectively control the deformation of the surrounding rock,and the monitoring data verify the scientific and engineering applicability of the method,which provides a theoretical basis and practical reference for the disaster management of tunnels in karst areas.关键词
岩溶/围岩等级/支护/变形Key words
Karst/Surrounding rock grade/Support/Deformation分类
交通工程
