Geotechnical Engineering and Drilling


TRC’s geotechnical professionals provide you with a “window to the underground” that helps you take a proactive approach to project planning and design. Our experts analyze the physical and structural properties of soil and rock, then formulate an effective plan for you to successfully build on and within those materials.


TRC’s geotechnical engineering experts plan and execute detailed site investigation programs that assess the physical and structural properties of soil and rock. We analyze your site’s subsurface complexities, including seismic vulnerability if applicable, and evaluate alternatives that can be applied to address your project’s unique needs. Our in-house fleet of modern test boring rigs, Pile Dynamic Analysis (PDA) testing equipment and in-house AMRL accredited laboratory facilities futher ensure the integrity of test results and speed project delivery.

TRC investigates and engineers practical solutions for all types of horizontal and vertical structures, marginal sites, and construction issues, and for such natural hazards as earthquakes, landslides, sinkholes and soil liquefaction. We serve public- and private-sector clients alike, and are adept at working in coastal regions, mountainous terrain and anything in between.

Our Geotechnical Engineering and Drilling services include:


  • Foundation investigations
  • Geotechnical site assessments (preliminary, final and feasibility)
  • Expert testimony/litigation support
  • Construction inspection and testing
  • Earthquake engineering
  • Fault investigations
  • Levee evaluation
  • Liquefaction analysis
  • Pavement evaluation and design
  • Site stabilization/ground modification programs
  • Earth retaining system evaluation/design
  • Soil and rock slope stability studies
  • Soil and rock mechanics

Specialized Analysis

  • CAPWAP and WEAP pile analysis
  • Pile Dynamic Analysis (PDA) testing
  • Vibration monitoring

Drilling (Test Borings)

  • Earth drilling and sampling
  • In-situ testing
  • Instrumentation installation
  • Pavement/slab coring
  • Rock coring (N or H sizes)
  • Well installation (up to 4” OD)

Laboratory Testing

  • Visual and laboratory classification
  • Compacting testing
  • Consolidation tests
  • Direct shear tests
  • Moisture-density relationships
  • Permeability tests
  • Triaxial shear tests
  • Unconfined compression tests