A Study on Risk Control of Horizontal Directional Drilling for Large-Diameter Pipelines Crossing Large Rivers During the Construction
Horizontal directional drilling for long-distance,large-diameter pipelines across large rivers poses significant construction challenges attributed to intricate geological conditions and substantial drag resistance.This paper focuses on the analysis of risks encountered during the horizontal directional drilling of the Central Line Project of South-to-North Water Diversion,particularly in the New Chaobai River section.The identified risks encompass the surrounding environment,geological irregularities,construction technology,equipment failures,drilling tools,and directional control.In response to these challenges,this paper proposes corresponding control measures.The practical significance of the study is validated through insights gained from the selection of a horizontal directional drilling rig featuring an AC geomagnetic control system,the use of mud with varying ratios and properties tailored to different geological formations,and the adoption of water injection methods,especially through delivery trench and cat-back procedures for pipeline delivery.In addition,control measures such as water injection through PE pipelines inside steel pipelines during the dragging-back process are essential to ensure the drilling trajectory aligns with the design specifications.This approach effectively mitigates risks such as collapse,shrinkage,damage to the anti-corrosion layer of the pipe,and fractures in weld joints during the back-dragging phase.The relevant experience is worth learning from.
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