Ground Displacement Monitoring During Horizontal Directional Drilling Other Trenchless Installations

摘要

Horizontal directional drilling (HDD) methods involve steerable tunneling systems for bothrnsmall and large diameter lines. HDD is a two-stage process. The first stage consists of drilling arnsmall diameter pilot hole along the desired centerline of a proposed line. The second stage consists ofrnenlarging the pilot hole to the desired diameter to accommodate the utility line and pulling the utilityrnline through the enlarged hole. The HDD methods have the ability to track the location of the drill bitrnand steer it during the drilling process. The result is a greater degree of precision in placing thernutilities. HDD has traditionally been used for cable and pressure pipeline installations. In recentrnyears, there have been innovative applications for HDD, such as, gravity pipe installations, pipernremoval, pavement stabilization and environmental applications such as horizontal wells and gasrnextraction applications in sanitary landfills.rnGround displacements and borehole stability are always of prime concern during HDDrninstallations under pavements, in close proximity to existing buried utilities and structures. Stablernboreholes also relate to successful completion of the projects. The Trenchless Research andrnDevelopment Center (TRDC) at University of Missouri -- Columbia, is conducting researchrnconcerning ground displacement monitoring and borehole stability in cooperation with MissourirnDepartment of Transportation (MoDOT) and several industry participants. The objective of thisrnresearch is to study the cavity expansion within the soil caused by the HDD process and to study therndisplacements of the soil in the vicinity of the cutterhead, reamer and at the ground surface.