In-Situ Testing: Understanding Soil Behaviour On-Site

In-situ testing forms a cornerstone of geotechnical engineering, offering direct insights into the physical properties of soil in its natural environment. These tests, conducted on-site, are indispensable for construction projects, as they help design foundations, assess soil stability, and understand how soil behaves under various conditions.

Below are some of the common in-situ testing capabilities we have here at GCL;

Plate Bearing Tests

Plate Bearing Tests are crucial for understanding the load-bearing capacity of the ground, particularly for designing pile / crane mats or for road construction. By applying pressure through a steel plate at the surface level and measuring the soil’s response, engineers can calculate the ultimate bearing capacity of the soil. This test helps prevent structural failures, ensuring the ground can withstand the proposed construction’s weight without excessive settlement.

Pocket Penetrometer Tests

The Pocket Penetrometer Test offers a quick and efficient method to determine the shear strength of cohesive soils, essential information for predicting how soil will behave under structural loads. This handheld device, when pushed into the soil, measures resistance, providing an immediate indication of the soil’s consistency and compaction level. While not a substitute for comprehensive laboratory testing, it provides valuable preliminary data on-site.

Standard Penetration Tests (SPTs)

Standard Penetration Tests are widely used in geotechnical engineering to assess the relative density and angle of internal friction of the soil. The test involves driving a split-barrel sampler into the soil layer using a heavy weight (hammer) and counting the number of blows required. The ‘N-value’ obtained reflects soil strength, offering vital information for foundation design and other construction considerations.

Infiltration Tests (BRE 365)

Infiltration Tests, guided by BRE 365 standards, are conducted to measure the rate at which water penetrates the soil. This test is vital for sustainable drainage systems (SuDS), helping to prevent waterlogging and assessing the feasibility of infiltration-based stormwater management solutions. By understanding how quickly water disperses into the ground, engineers can design effective drainage systems that mitigate flood risks.

Percolation Tests (BS6297)

Percolation Tests, performed according to BS6297 standards, determine the soil’s ability to absorb water, crucial for designing septic tank drainage fields and other wastewater management systems. The test involves saturating a hole with water and measuring the drop in water level over time. The results inform the suitability of the soil for soakaway systems, ensuring environmental protection and regulatory compliance.

WAC Testing

Waste Acceptance Criteria (WAC) Testing assesses soil waste for its suitability for disposal at landfill sites. This analysis determines the presence of contaminants and the leaching behaviour of waste materials, ensuring that the waste meets regulatory criteria for landfill. WAC Testing is essential for environmental protection, helping to prevent the contamination of surrounding land and water resources.