• DFI Europe
  • DFI India
  • DFI Trust

Ground Improvement

Addressing design and performance of ground improvement technologies for foundation projects and liquefaction mitigation, including vibratory stone columns, vibrocompaction, vibro concrete columns, aggregate piers, dynamic compaction, wick drains and grouted inclusions.

Committee Chair

Tim Siegel, P.E., G.E., D.GE
Dan Brown and Associates PC

Tim Siegel serves as CEO and Senior Principal Engineer at Dan Brown and Associates PC.  Tim has over 25 years of experience in foundation design and construction.  He is active in the industry by serving on committees within the Deep Foundation Institute, Geo-Institute, and the Transportation Research Board.  He is also currently Co-Editor-in-Chief of the DFI Journal.

Wick Drains (photo courtesy of Menard)



Guidance for developing effective and appropriate specifications for various ground improvement technologies

DFI Guidance for Drafting Specifications for Ground Improvement – The Ground Improvement Committee developed this guidance to provide owners, agencies, designers and specifiers with a minimum framework for preparing specifications for ground improvement work. The framework is intended to provide a consistent structure that is technology-neutral to allow for the best application of technology to the project needs.

Wick Drain Guide Specification (Method) – Wick drains, also known as prefabricated vertical drains, PVDs, PV Drains, and band drains, are light-weight, flexible geocomposite drains that are inserted into the ground primarily for purposes of enhancing or altering drainage in subsurface layers. The most common use of wick drains is to accelerate consolidation in fine-grained, slow-draining layers. This specification is provided as a Word document that can be tailored to project-specific conditions.

Rigid Inclusions Task Force

Discussing aspects of design and performance of rigid inclusions as ground improvement.


  • Dr. Juan Baez – Chair
  • Dr. Lisheng Shao
  • Ms. Sonya Swift
  • Mr. Ravi Vedantham 
  • Dr. Terry Holman
  • Mr. Tim Siegel

DFI Magazine article on Geo-Institute panel on rigid inclusions (March 2020)

Committee-Endorsed Research

Completed Projects

Projects in Progress

  • Seismic Performance of Rigid Inclusions – Phases I and II (Oregon State University, Prof. Armin Stuedlein, Ph.D., P.E.
  • Development of a Simplified Methodology to Evaluate the Factor of Safety for Basal Stability and the Magnitude of Lateral Spreading for CSEs Supported on Rigid Inclusions (Phase II), Prof. Aaron Gallant, Ph.D., P.E.
  • Reinforcing mechanisms of soil-cement columns in liquefiable sand underneath an embankment during strong earthquake loading, Montana State University, Prof. Mohammad Khosravi, Ph.D.

Codification Standards

Members serving on ASCE/SEI committee for developing a foundations standard, including a new ground improvement standard.

NHI Ground Improvement Partnership

Partnership with FHWA to deliver ground improvement courses to departments of transportation and industryaccelerate project delivery


FHWA Geotechnical Engineering Circular No. 13 Ground Modification Methods, Reference Manual – Volumes I and II.

GeoConstructability – An Owner’s Guide to Obtaining Essential Geotechnical Information for Construction (documents the type of geotechnical information  that contractors need to estimate, plan and execute foundation projects)