Measuring-While-Drilling: Transforming Geotechnical Site Characterization Drilling

"Interest in Measuring-While-Drilling (MWD) within the U.S. geotechnical industry has been growing significantly over the last several years. This largely began after the Federal Highway Administration (FHWA) promoted the use of MWD as part of an effort known as Advanced Geotechnical Methods of Exploration (A-GaME) starting in 2019, which significantly increased visibility and provided training and resources to help state departments of transportation get started with MWD. FHWA, in partnership with the Deep Foundations Institute (DFI), hosted an online MWD Users Group that meets monthly to share information and foster discussion, and it regularly draws a diverse group of approximately 50 attendees each month from academics, and public and private sector organizations. At least 20 state transportation agencies and federal agencies, including Federal Lands Highway, US Bureau of Reclamation, and US Army Corps of Engineers, have experimented with, or implemented MWD as one of their subsurface exploration tools. The American Association of State Highway Transportation Officials (AASHTO) is currently finalizing a draft standard on MWD that incorporates U.S. drilling practices. The draft standard passed balloting within the AASHTO Technical Subcommittee on Geotechnical Exploration, Instrumentation, Stabilization and Field Testing in May 2025, and is anticipated to be published in 2025.  Progress with MWD within the U.S. is palpable, but more work is needed to maximize the value that MWD affords and to transform drilling practices for geotechnical site characterization. Users of MWD are seeing its benefits for determining stratigraphy boundaries, making relative comparisons of materials, and for improving drilling efficiency. There remains great interest in developing correlations to geo-material characteristics, engineering properties and behavior, which would allow MWD data to be used for more deterministic subsurface characterization and even directly for design. This paper provides an overview of MWD practice within the U.S. and illustrates the growth this technology has seen in recent years. It then explores what research and data gathering efforts are needed to see even greater value. Lastly, it provides a look toward the future of MWD with respect to developing interests and practice to make this transformation a reality."