Factors Affecting Productivity of Horizontal Directional Drilling

摘要

Horizontal Directional Drilling (HDD) is a suitable construction method for crossing beneath obstacles,such as rivers and lakes,highways,or special areas such as airport runways.In particular,HDD is the most appropriate,cost effective method for constructing new water and wastewater pipelines where excavation is not practical or possible.HDD operations are capable of traversing various soil conditions and meeting a wide variety of project requirements (pipe size and material,placement distance and depth).Nonetheless,the specific soil conditions and project details are important factors in determining the productivity of the overall operation,and these conditions must therefore be carefully investigated during the HDD design phase.The present case study provides observed HDD productivity values (ft/hr) in different soil formations (shaly clay,sandy shale,and silty clay) based on operations at a single HDD site,serving as a pilot project.In particular,the variation in HDD productivity during the reaming stage is provided based on the soil and project conditions encountered (diameter),while other conditions (e.g.,contractor and HDD machine) remain constant.