Vibration reduction technique of shield construction in water-rich karst strata

In shield tunneling within karst formations, the vibrational effects often impact the safety of surrounding residents and buildings. The study of construction vibration mitigation measures holds significant importance. Based on the shield tunneling project in the Huang-Shang section of the Xuzhou Metro Line 6, this paper studies the causes, propagation characteristics and influencing factors of ground vibration caused by shield construction. Three effective mitigation measures were identified: (1) Optimization adjustment of shield tunneling parameters; (2) Grouting with mixed bentonite; (3) Layout of vibration reduction boreholes. Each mitigation measure was individually tested for its impact on ground vibration. The comprehensive application of the three measures in shield tunnel construction was analyzed to assess their combined effectiveness. The integration of actual engineering measurements indicates that boreholes provide the best damping effect. Furthermore, the application of multiple mitigation measures resulted in an overall 60% reduction in ground vibration, significantly mitigating the impact on residential structures on the ground. This study provides valuable references for vibration reduction measures in other engineering projects. • Contains an example of shield construction in water-rich karst strata; • Multiple vibration reduction measures are applied in engineering practice, and the results are analyzed and compared; • The comprehensive damping effect is as high as 60%, which ensures the safety of the surrounding buildings when the shield machine passes through. • This case study focuses on how to solve practical problems. A large amount of literature research has been carried out for each vibration reduction measure and adjustments have been made according to the actual working conditions. This is a successful exploration and application for the lack of research on shield vibration reduction measures.