Study on the Influencing Factors of Over-Excavation of Drilling and Blasting Diversion Tunnels Based on Control Charts
The phenomenon of over-excavation often occurs in the construction of water conveyance tunnels by drilling and blasting method,and it is of great significance to use the control chart method to identify the influencing factors of over-excavation.This paper took the drilling and blasting method of the Kuncheng Tunnel as the research object,collected the over-excavation data of the field measured section,improved control map model based on the sample mean distribution,and made an analysis of statistical characteristics of tunnel over-digging under different surrounding rock levels;explored the potential rules based on statistical characteristics of over-excavation,as well as the influence factors of surrounding rock geological conditions,blasting parameter design,construction method,human factors,different parts and groundwater.The study shows that:based on the improved control map model,it can intuitively determine whether the tunnel blasting over-digging is in a stable and controlled state,and quickly identify the controllable and uncontrollable over-digging influence factors;controlled factors include blasting parameter design,blasting construction methods and human factors,while uncontrollable factors include surrounding rock geological conditions and groundwater;the over-digging value of the tunnel arch shoulder and the vault is the largest,and the side wall over-digging is relatively small;the over-excavation positions are concentrated in specific strata or topography,and the geological junction positions are more likely to produce over-excavation,and the over-excavation value will change periodically with the hard-medium-weak strength of the rock layer.These research results provide a basis for the subsequent control of tunnel over-digging and the improvement of the blasting effect.
diversion tunneldrilling and blasting methodover-excavationimpact factorcontrol chart
NETL
NSTL
万方数据
维普
