Accuracy of Pull Force Estimation for Steel Pipe Installations Using Horizontal Directional Drilling: Review of 200 Case Studies

Abstract

Pull force estimation in horizontal directional drilling (HDD) is an essential step during the planning phases. Pull force calculation can be relatively complicated when considering variations during the HDD construction process compared with the design phases. Simplifications and assumptions need to be made as part of current design practice to approximate the pull forces expected in HDD pullback operations. However, a comprehensive assessment of pull force prediction accuracy has not been completed to date. A brief review of the current design practice and industry accepted engineering assumptions for pull force calculation for steel pipe is presented in this work. Data from 200 recent commercial HDD projects were studied to compare actual and predicted pull forces. The accuracy of the predictions was investigated based on different project categories such as pipe size, crossing length, geotechnical conditions, and equipment sizes. This study suggests that assumptions for pull force estimations need to be selected based on project-specific scopes and construction execution to increase the accuracy of pull force predictions.