Geotechnical Engineering, Surveys & Drilling Services

Every development begins with the ground beneath it.

A site may appear ready for construction, yet underlying conditions may include soft or compressible soil, uncontrolled fill, shallow groundwater, shifting rock conditions, or other subsurface features. These conditions can affect foundation depth, excavation, site grading, pavement systems, and construction methods.

Intertek develops geotechnical programs based on the proposed project, anticipated structural loads, site characteristics, and available geologic information. Depending on the scope, services may include preliminary studies, subsurface exploration, drilling and sampling, laboratory testing, engineering analysis, reporting, and construction-phase consulting.

The findings help project teams identify potential engineering constraints and evaluate options for earthwork and foundations before construction begins.

Geotechnical engineering is a branch of civil engineering focused on the physical and mechanical properties of soil and rock and on how they interact with engineered structures.

Geotechnical investigations apply that expertise to a specific site through drilling, sampling, field testing, laboratory analysis and engineering calculations. The findings help project teams understand how soil, rock and groundwater may respond to structural loads, excavation, changes in moisture and construction activity.

Common applications include the design and analysis of foundations, slopes, embankments, retaining walls, tunnels, pavement systems, floor slabs, and earthwork. Investigations may also assess groundwater conditions that could affect design or construction.

Surface conditions alone do not tell the full story of a project site. Unexpected subsurface conditions found during construction may require changes to the foundation, additional excavation, soil improvement, dewatering, or revisions to the construction sequence. A geotechnical investigation provides representative site data earlier, so the findings can still inform planning and design.

Geotechnical investigations do not remove all subsurface uncertainty. They provide findings and engineering recommendations based on the completed field explorations, laboratory results, and project information available at the time of the study.

Intertek supports projects through a combination of field exploration, laboratory testing, and engineering analysis.

The appropriate combination of services depends on the project type, design stage, site conditions, and engineering questions to be addressed.

A subsurface investigation gathers information about the soil, rock, and groundwater beneath a proposed project.

The geotechnical team begins by reviewing available site plans, project information, and geologic data. Engineers then develop an exploration program based on the proposed construction, anticipated loads, and site conditions.

Field exploration may include soil borings, rock coring, drilling, sampling, test pits, groundwater observations, and in-place testing. Field-collected samples may be sent to a geotechnical laboratory for classification and additional testing.

The number, location, and depth of explorations vary by project. A roadway corridor, building, retaining wall, and utility project each pose distinct engineering questions and require a scope tailored to the planned work.

Drilling provides direct information about the materials beneath a site.

Soil borings can document changes in soil type, consistency, and density with depth. Rock coring may be used to evaluate the depth and condition of bedrock. Test pits can provide a broader view of shallow soil, fill, or buried materials.

Field programs may also include Standard Penetration Testing, groundwater sampling and monitoring, or other exploration methods selected for the project.

Field observations are evaluated alongside laboratory results and engineering analyses. Together, this information supports the findings and recommendations presented in the geotechnical report.

Intertek-PSI conducts more than 2 million individual field and laboratory material tests each year.

Geotechnical laboratory testing provides data on site characteristics and on how soil may respond to applied loads, moisture, and other stresses. The testing program is developed around the materials encountered and the information needed for engineering analysis.

Laboratory results may be evaluated with engineering analysis and, when appropriate, numerical modeling to support project-specific design, construction, and maintenance recommendations.

Testing is conducted by engineers and technicians using established procedures and industry practices, with oversight from Intertek-PSI’s engineering leadership.

Foundation design depends on the proposed structure, anticipated loads, and the capacity of the underlying soil or rock.

Intertek evaluates subsurface conditions and structural information to develop project-specific foundation recommendations. Depending on the soil profile and proposed construction, recommendations may address shallow and deep foundations, site preparation, ground improvement, or other earthwork and foundation solutions.

Engineering analysis may consider bearing capacity, total and differential settlement, groundwater, lateral loads, seismic hazards, and general construction conditions.

The geotechnical report may also provide recommendations for subgrade preparation, floor slabs, excavation, fill placement, and other work that affects foundation performance.

A preliminary geotechnical study is a smaller-scale initial site review conducted before project plans and structural characteristics are fully developed.

The study can provide an early understanding of expected geologic and soil conditions, as well as potential foundation considerations. It may include a review of available records, limited subsurface exploration, laboratory testing, preliminary site characterization, and recommendations for the final field exploration program.

Preliminary studies can support early site selection, feasibility discussions, and development planning. They do not replace a complete project-specific study once the layout, loads, and design requirements are known.

A complete geotechnical study is developed for a defined project with a known or anticipated layout, structural characteristics and loading conditions.

The scope may include subsurface evaluation, drilling and sampling, site characterization, soil testing, construction materials investigation, bearing capacity analysis, foundation recommendations, settlement analysis, and general construction considerations.

Depending on the project, the study may also address retaining walls, slope stability, pavement design, geological studies, seismic hazards, liquefaction, geohazards, vibration, and groundwater flow.

The resulting geotechnical report documents the conditions encountered and offers engineering recommendations for the proposed construction.

Roadways, rail systems, and other transportation corridors may cross changing terrain, soil, rock, and groundwater conditions.

Intertek provides geotechnical corridor studies that can support foundation, embankment, retaining wall, and pavement design. Services may include subsurface investigations, drilling and sampling, geotechnical risk assessments, groundwater sampling, instrumentation, monitoring and corridor-level fatal-flaw analysis.

Transportation work may also address borrow materials, flood and stormwater management facilities and design requirements under the American Association of State Highway and Transportation Officials’ Load and Resistance Factor Design specifications.

Combining geotechnical engineering with environmental, infrastructure and construction materials services can provide coordinated support across planning, design and construction.

Utility and pipeline projects often extend across multiple geologic settings, environmental conditions, and regulatory jurisdictions.

Intertek’s corridor services may support route selection, alignment planning, subsurface investigation, drilling, geotechnical risk assessment, groundwater sampling, geotechnical quantities estimation, and foundation, embankment, or retaining wall design.

These projects may also require environmental assessments, environmental impact statements, permitting and regulatory compliance, wetland and protected-species analysis, cultural-resources evaluation and National Environmental Policy Act documentation.

Coordinating geotechnical and environmental services can help project teams evaluate the engineering and regulatory conditions encountered along a proposed corridor.

Soil, rock, groundwater, and terrain vary from one region to another. Local regulations and construction practices also influence how projects are investigated, designed, and built.

Intertek-PSI’s national footprint gives clients access to engineering teams familiar with local terrain and regulatory requirements, backed by resources that can support fast-track schedules and major projects.

Geotechnical engineering provides the greatest value when findings are available early enough to inform project decisions.

A preliminary study may support site selection, acquisition, or feasibility planning. A complete geotechnical investigation can provide recommendations as structural and civil designs are developed. During construction, geotechnical professionals can review field-exposed conditions and address questions as work progresses.

Early involvement gives project teams time to consider subsurface findings in plans, budgets, schedules and construction strategies.

A geotechnical report documents the investigation methods, subsurface conditions, laboratory results, engineering analysis, and recommendations for the project.

Depending on the project scope, the report may include:

• Site and proposed construction information
• Exploration locations and depths
• Soil, rock, and groundwater conditions encountered
• Laboratory testing results
• Engineering analysis and design parameters
• Recommendations for foundations, settlement, earthwork, pavements, retaining walls, slopes, groundwater, and construction

The report should be reviewed as a complete document because its findings and recommendations are based on the proposed project and the conditions identified at the exploration locations.

Geotechnical conditions become visible across a broader portion of the site as excavation and construction proceed.

Intertek can provide geotechnical consulting during construction to evaluate exposed conditions, respond to field questions, and determine when additional review, testing, or analysis may be appropriate.

Intertek also provides construction materials testing and inspection for concrete, soils, asphalt, structural steel, masonry, and other materials. Coordinating geotechnical and construction materials services can provide continuity from the initial subsurface investigation through construction.