Safety Technical Analysis of Construction Beneath Existing Railway Tunnels
When a new tunnel intersects with an existing tunnel in a plane,the construction scheme of overpassing or underpassing in the vertical direction is typically chosen.Among them,the underground excavation construction beneath an existing tunnel is particularly complex and has a significant impact on the existing tunnel.Improper selection of excavation methods and support measures may lead to settlement and deformation of the existing tunnel,even endangering operational safety.Especially when underpassing a railway tunnel,the requirements for track settlement are very strict,not exceeding 2 mm.Therefore,controlling the settlement and deformation of the existing tunnel is crucial,which necessitates the selection of appropriate excavation methods and effective advanced support measures to ensure the safety of the existing railway tunnel.In practical engineering,the use of non-blasting excavation,double-side heading method,and Φ299 large-diameter pipe roof technology for underpassing existing railway tunnels has not caused adverse effects on the existing railway and has reduced the risks of underground excavation operations.This provides valuable experience and reference for similar underground excavation projects.
Small ClearanceUnderpassingExisting Railway TunnelLarge-diameter Pipe Roof
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