Beyond the Foundation

27 Feb 2026

How Early Geotechnical Data Influences Planning, Construction Risk, and Long-Term Performance

Geotechnical data is often associated solely with foundation design, but subsurface conditions influence many decisions that occur well before footing sizes or pile depths are finalized. Soil properties, groundwater levels, and variability across a site affect planning, constructability, and geologic long-term performance.

When these conditions are identified early, project teams can adjust layouts, grading, and construction methods before breaking ground. When they are not, impacts often surface later as schedule delays, unforeseen costs, and field changes that are difficult to resolve once construction is underway.

Site Planning Begins Below Grade

Early geotechnical investigations define soil types, rock layers, groundwater levels, and lateral variability. That information directly affects building placement, grading strategies, earthwork quantities, excavation depth, and utility routing.

On one project, early borings revealed significant variability in soil strength across the site, along with groundwater closer to the surface than anticipated. Portions of the site could support shallow foundations, while other areas required ground improvement to meet performance requirements.

Because those conditions were identified during planning, the design team adjusted building placement and revised excavation and dewatering plans before construction began. Pavement sections were also modified in areas with lower subgrade strength. Addressing those issues early helped avoid major redesigns and change orders once construction was underway.

Slopes, Retaining Systems, and Load-Bearing Surfaces

Geotechnical conditions determine the design and performance of more than just the primary structure:

• Slope stability: Soil strength, stratigraphy, geometry, and seepage potential determine whether slopes remain stable or require reinforcement, particularly on sites with elevation changes or transportation corridors.
• Retaining systems: Wall type, reinforcement, drainage, and embedment depth depend on lateral earth pressures and site-specific soil behavior.
• Pavements and slabs: Subgrade strength, compressibility, and moisture sensitivity affect thickness, reinforcement, and long-term durability.
• Operational performance: Settlement or cracking can disrupt equipment, racking systems, and daily operations, especially in warehouses and industrial facilities.

Designing these systems based on measured subsurface conditions helps avoid excessively conservative solutions that increase cost without adding performance value.

Construction Methods and Risk Management

Subsurface conditions shape construction means and methods. Shoring systems, trench and excavation safety plans, and sequencing decisions depend on soil type and groundwater behavior. When conditions are not well defined, contractors face greater uncertainty, often leading to change orders and claims tied to differing site conditions. Integrating geotechnical findings with construction-phase observation and testing helps teams respond to field conditions efficiently and manage risk as work progresses.

Performance Over the Life of the Project

Geotechnical considerations extend far beyond construction. Soil movement, erosion, and groundwater changes can affect structures for decades. Foundations, pavements, bridges, tanks, embankments, slopes, and underground utilities all rely on long-term subsurface stability. Understanding how soils are likely to behave over time supports proactive maintenance planning and lifecycle cost management.

How Intertek Supports Geotechnical Decision-Making

Intertek provides geotechnical engineering and subsurface investigation services that support projects from planning through construction, including field exploration, laboratory testing, engineering analysis, and construction-phase observation. By connecting geotechnical data to design and construction decisions, Intertek helps teams identify site-specific risks early and reduce uncertainty throughout the project lifecycle.