Study on Prediction and Construction Measures for Water Gushing in Fractured Sandstone Tunnel with Abundant Water
Taking the Tianheshan Tunnel of the newly built Heshun-Xingtai Railway Project as the research background,this article comprehensively analyzed the existing methods for predicting water gushing in combination with the hydrogeological conditions of the study area.The normal water gushing of the main tunnel was calculated using the groundwater runoff depth method,and the maximum water gushing was predicted using the Sato Bang Akira formula.Compared with the measured data,corresponding measures for preventing water gushing during construction were proposed.The results indicate that the interlayer water in sandstone is multi-layered groundwater,containing a large amount of groundwater,providing favorable conditions for the enrichment and runoff of groundwater.The predicted normal water volume of the tunnel is approximately 35 973.5 m3/d,themaximumwater gushing is about 71 947 m3/d,and the strong rich water section accounts for 76.5%.The predicted maximum water gushing and the actual maximum water gushing show a relatively consistent variation pattern.After removing discrete points,the average ratio of the measured maximum water gushing to the predicted maximum water gushing is 1.06.This indicates that the calculation accuracy of using the water gushing prediction method meets the accuracy requirements of engineering construction and has good adaptability to water-rich fractured sandstone formations.A construction control plan of"advanced prediction+advanced pre grouting"has been proposed.Practice has shown that this control plan has a good effect and provides a dry or low water environment for tunnel excavation construction.
water-rich sandstonetunnel engineeringbroken zoneprediction of water gushingconstruction governanceSato Bang Akira formula
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