About

Don J. DeGroot is a professor in the Department of Civil and Environmental Engineering at the University of Massachusetts Amherst, affiliated with the Riccio College of Engineering. His research areas include energy, environment, and water, as well as smart communities and infrastructure. He holds a Doctor of Science (S.D.) degree in Civil Engineering from the Massachusetts Institute of Technology, earned in August 1989, and a Master of Science in Civil Engineering from MIT, obtained in June 1985. His undergraduate degree is a Bachelor of Science in Civil Engineering with Great Distinction from Concordia University, earned in May 1983, and he also holds a Diploma of Collegial Studies in Civil Engineering Technology from Dawson College, obtained in August 1979. His professional focus encompasses geotechnical engineering, contributing to the advancement of sustainable and resilient infrastructure systems.

Research topics

• Composite material
• Materials science
• Geology
• Mineralogy
• Geotechnical engineering
• Computer Science
• Algorithm
• Acoustics
• Mathematics
• Marine engineering
• Physics
• Structural engineering
• Mechanical engineering
• Engineering
• Electrical engineering
• Geometry
• Chemical engineering
• Nanotechnology

Selected publications

• CHARACTERIZATION OF A NEW JERSEY COASTAL PLAIN AUTHIGENIC GLAUCONITE SAND TEST SITE

  Canadian Geotechnical Journal · 2026-04-10

  articleSenior author

  Glauconite is an iron- and potassium-rich mineral of the mica family. It evolves at the soil-water interface through chemical exchange, its maturity linked to exposure duration at the seafloor and source element availability. Glauconite sands have been discovered at offshore wind lease areas along the U.S. Atlantic Outer Continental Shelf, leading to uncertainties in pile foundation installation and long-term performance. This paper describes site characterization activities from the Piling in Glauconitic Sand (PIGS) Joint Industry Project test site, located along the New Jersey Coastal Plain. In situ testing, laboratory-based geological, microstructure, and soil index testing, and advanced soil behavior measurements are presented in detail. Comparisons to selected silica sand-based cone penetration testing (CPT) correlations are made, highlighting the cautions needed for deriving soil parameters in this unique material. The measured properties and observed behavior exhibit a transition from sand-like to clay-like behavior during particle crushing due to compression and shear stresses from impact pile driving, which deviate from conventional sedimentary clays and sands. This transition can lead to changes in soil microstructure, plasticity, strength, and permeability, among others. The extensive dataset provides a reference for geotechnical practioners and researchers encountering other glauconite sand deposits or similar transitional sediments.

  PublisherDOI

• Direct and Interface Shear Behavior of an Authigenic Glauconite Sand from the Coastal Plain of New Jersey

  Journal of Geotechnical and Geoenvironmental Engineering · 2025-05-09

  article

  Glauconite sand, a green-colored, iron–potassium micaceous peloid known for its high crushability, has been found at locations in Europe and the United States where offshore wind development is currently underway. Crushing the material increases the fines content and transforms its behavior from sandlike to claylike, which can affect shaft resistance and end bearing during pile driving and long-term axial loading. The strain rate during pile driving can exceed 106% per hour, in which undrained viscous effects dominate the shaft resistance. Following installation, shaft resistance can exhibit a drained or an undrained response, depending on the nature of static and cyclic operational loads and the degree of particle crushing of the soil and its associated drainage properties. Direct shear and interface shear tests were conducted to study the effects of shear rate, interface roughness, and extent of particle crushing on the shear behavior of glauconite sand. Tests were conducted on natural and artificially degraded glauconite sand as well as Ottawa 20-30 sand and Boston Blue Clay to benchmark the results against typical sand and clay behavior. Results show that the peak and residual shear stress decrease as the shear rate increases, transitioning from drained to partially drained conditions. With continued increases in shear rate, viscous effects were observed to increase the shear resistance of degraded glauconite sand. The peak and residual shear stress also decreased with increasing degradation, reaching a minimum after mixing the soil in a dispersion cup for 60 min. The drained peak and residual shear stress between soil and steel followed expected trends related to surface roughness, while roughness effects under undrained conditions were less conclusive. Results are discussed in the context of implications for offshore pile foundation design.

  PublisherDOI

• Centrifuge Modeling of the Monotonic Capacity of Offshore Ring Anchors in Clay

  2025-02-27 · 1 citations

  articleCorresponding

  Offshore wind turbines have become a feasible solution to meet the growing demands for renewable energy. However, offshore wind turbines with fixed foundations become increasingly economically and technically unfeasible at locations with large water depth. At these locations, floating platforms supported by mooring system and subsea anchors are a more feasible solution. Deeply embedded ring-shaped anchors can have greater efficiency than piles and caissons and greater capacity than drag anchors. In this paper, the result of a series of monotonic centrifuge load tests in clay is presented, with a focus on evaluation of the effect of loading inclination and anchor embedment depth on the tensile capacity and load-displacement response of the ring anchors. Tests were performed at the UC Davis Center for Geotechnical Modeling (CGM) with a scaling of 70g. The ring anchor models were embedded in normally consolidated kaolin clay. The clay shear strength was estimated from T-bar soundings performed in-flight. The anchors were connected to an actuator using taut steel wire ropes, and the line load, displacement, and inclination were measured. The results indicate that the capacity of the ring anchors increases as the loading inclination changes from vertical to horizontal. Increasing the embedment depth also resulted in an increase in capacity; however, the capacity normalized by the clay’s undrained shear strength is independent of depth. The interaction diagram describing the capacity as a function of load inclination and depth indicates that the ring anchor’s horizontal tensile capacity is much greater than its vertical capacity. Furthermore, analyses also show that the system stiffness increases as the load inclination angle increases. Overall, the results of this study show that the ring anchor could be a potential foundation solution with greater material efficiency than other alternatives.

  PublisherDOI

• Design and analysis of shared anchor layouts for floating wind farms in deep waters

  Ocean Engineering · 2025-01-08 · 10 citations

  articleSenior author
  PublisherDOI

• Navigating the Ascent

  GEOSTRATA Magazine · 2025-10-01

  article

  Limiting global atmospheric temperature increase will require electricity generation from renewable sources such as offshore wind energy development, which has increased exponentially over the past two decades. An offshore wind farm can exceed 100 individual foundations built across seabed areas of 400 km2 (roughly the size of Philadelphia), each supporting a structure nearly the height of the Eiffel Tower (330 m). In the U.S., geodata (i.e., seabed geology and geotechnical properties) are required at every turbine location per the U.S. Bureau of Ocean Energy Management guidelines. To install just one-fifth of the 2,500 GW of renewable energy needed to meet net zero goals by 2050 (a conservative assessment for offshore wind), more than 120,000 km2 of seabed will be needed (roughly the size of Pennsylvania), and over 30,000 turbines built at today’s 15 MW capacity. Site characterization for this planned construction will require more than 1.5 million m of in-situ testing, 500 km of geotechnical borings, and 10 million km of geophysical survey lines.

  PublisherDOI

• Implications of glauconite sands on US offshore wind development

  2024-05-22

  articleSenior author

  Glauconite is a high specific gravity, greenish black iron-potassium pellet found in shallow marine depositional environments along the US Atlantic Continental Shelf in areas associated with offshore wind developments. Glauconite affects the geotechnical properties of sediments in which it forms and poses risks to foundation installation and performance due to its transformation from a coarse-grained to a fine-grained material due to crushing. Dense, authigenic deposits exhibit less compressibility than other crushable soils, but degrade rapidly under loading due their high internal porosity, linked to their maturity. In situ cone penetrometer testing results exhibit high tip resistance, high sleeve friction, and positive or negative excess pore pressures depending on microstructure, hindering site characterisation using standard soil classification charts. Examples of high glauconite content (> 90% by weight) sand behaviour from onshore deposits along the Atlantic coast are presented, as part of the Joint Industry Project: Piling in Glauconitic Sands (PIGS). Soil properties are shown to be highly sensitive to initial specimen conditions and preparation method, affecting particle size distribution, plasticity and thixotropy, and shear strength. Its implications on offshore geotechnical site investigation and pile foundation design are discussed.

  PublisherDOI

• Atterberg Limits of Two Crushed and Natural Glauconite Soils

  2024-02-22

  articleCorresponding

  Glauconite is the name of a mineral and soil containing significant quantities of iron and potassium varying in color from green to black, linked to its geological history. These soils are problematic in nature and exhibit potentially hazardous responses related to the construction of foundations. This is in part due to the difficulties in quantifying their geotechnical properties and how easily these properties change. Sand-sized glauconitic particles are often fractured, which increases their crushability, transitioning from sand-sized to fine-grained particles with cohesive behavior. This has led to geotechnical challenges including difficulty in pile driving and the potential for refusal. Glauconite has been shown to adhere to pile walls, which increases pile driving resistance. This may be a problem as glauconite deposits can be found along the eastern coast of the US in offshore wind lease areas. In this study, two glauconitic sands from the East Coast of the US are investigated for differences in their Atterberg limits in their natural and crushed state to quantify the increases of plasticity. Results on samples from the Late Cretaceous Navesink and Paleogene Hornerstown formations illustrate how sample preparation and particle crushing increases plasticity and changes USCS classification of glauconite soils. Additionally, it was found that these specific soils are acidic and when crushed their acidity levels and their colors can change.

  PublisherDOI

• Geological and geotechnical challenges of the East Coast United States for offshore energy transition

  2024-05-22 · 2 citations

  article1st authorCorresponding

  Offshore wind integrated site characterisation work being conducted at US East Coast lease areas relies on experiences gained in the European market although several unique challenges are emerging. Significant layering and spatial variability of soil units, boulders to the north, and calcareous soils to the south, and sediment mobility and scour each present challenges to ground model development. Furthermore, one of the more pressing challenges in the region is glauconite. This iron potassium mica characterises as a sand but transforms into a fine-grained soil upon shearing due to particle crushing. CPTu data show unique signatures of soil behaviour creating significant uncertainty for pile drivability analyses. Even routine soil index and classification testing is problematic. The paper covers the geologic history of the region and presents examples from site investigation work and research that highlight these geotechnical challenges and how they relate to foundation selection and cable routing.

  PublisherDOI

• Parametric Study on Deep-Water Taut Mooring for Floating Offshore Turbines

  2023-12-18 · 4 citations

  articleSenior author

  Abstract The utilization of offshore wind power in the United States has been a topic of discussion in recent times, and it has become apparent that floating wind technology holds the most potential in water depths exceeding 300 [1] [2] meters. However, to fully harness the benefits of this technology, it is imperative to enhance the station-keeping systems of the floating platforms. This work aims to present the findings from various parametric studies on the novel phenomenon called multiline anchors for floating offshore wind turbines. Since research on emerging wind technologies is shifting focus to deeper water to meet the growing demand of the renewable energy industry, the paper is based on taut-type mooring systems adopted in deep waters. The work entails the analysis of a multiline anchor connecting three different floating offshore wind turbine systems with taut mooring lines, with simulations conducted using the National Renewable Energy laboratory’s open-source tools, FAST and openFAST. The findings help to understand the implication of an increase in turbine size by a three-scale factor on the net multiline anchor forces, and the sensitivity of the environmental force direction on the multiline anchor forces. The influence of the taut angle on the multiline anchor forces in each water depth could also be understood.

  PublisherDOI

• Optimal Design of a Deeply Embedded Ring Anchor in Soft Clay Overlying Bedrock under Vertical Loading

  2023-03-23 · 2 citations

  articleCorresponding

  Offshore wind energy can play a significant role in addressing the clean energy policy goals of several countries, where floating offshore wind turbines (FOWT) can be preferred over the conventional fixed bottoms due to the water depth in the envisioned region. Since attractive sites for FOWTs will be located in extensive space in deep water, the potential sites are likely dominated by heterogeneous soils, such as clay to sand. This may require several anchor alternatives depending on soil type, resulting in increased costs and complexities of the single project. Therefore, the deeply embedded ring anchor (DERA) system has developed as a cost-effective solution for mooring FOWTs due to its attractive features: its installability in any soil type, its ability to be deeply embedded, availability to attach to various mooring systems, its multiline potential, and its compact size with high load capacity. In order to investigate the applicability of the DERA to various soil conditions in a specific site, this paper conducts a comparative example study and suggests the optimal design of the DERA in given site conditions. The findings from the study provide a platform to select a mooring system considering geometric constraints and estimate the required physical features of the DERA for achieving the needed load capacity. The results show that the DERA is a feasible and cost-effective alternative for the heterogeneous seabed, shallow water depth, and thin sediment layer due to its attractive features.

  PublisherDOI

Recent grants

• Collaborative Research: Improving the Sampling and Characterization of Intermediate Soils

  NSF · $330k · 2014–2019

• PIRE: Developing International Protocols for Offshore Sediments and their Role in Geohazards: Characterization, Assessment, and Mitigation

  NSF · $2.4M · 2005–2011

Frequent coauthors

• Jason T. DeJong

  55 shared

• Nicholas J. Yafrate

  Geosyntec Consultants (United States)

  50 shared

• Sanjay R. Arwade

  University of Massachusetts Amherst

  44 shared

• Ryan D. Beemer

  University of Massachusetts Dartmouth

  38 shared

• Mark Randolph

  University of Kassel

  34 shared

• Charles Aubeny

  Texas A&M University

  28 shared

• Alejandro Martínez

  University of California, Davis

  18 shared

• Junho Lee

  Mitchell Institute

  18 shared

Education

• ScD, Civil Engineering

  Massachusetts Institute of Technology

  1989