Falling Head Test Services
In-Situ Permeability Testing to Assess Groundwater Movement
Falling head testing is an in-situ method used to determine the permeability of soils below ground level. Chelmer provide falling head tests as part of their in-situ testing services, helping to assess how water moves through the ground and supporting a range of geotechnical and environmental investigations.
Understanding soil permeability is essential when assessing groundwater conditions, drainage behaviour and the suitability of the ground for development. By carrying out testing directly within boreholes, Chelmer are able to obtain results that accurately reflect site conditions.
Purpose of Falling Head Testing
The primary purpose of a falling head test is to measure how quickly water can pass through a soil stratum. This provides an indication of the soil’s permeability, which is a key factor in understanding groundwater behaviour and drainage performance.
Permeability data is used in a variety of applications, including the design of drainage systems, assessment of groundwater flow and evaluation of ground conditions for construction. Accurate results are particularly important where water movement may influence stability or long-term performance.
By determining how readily water can infiltrate and move through the soil, falling head testing provides valuable insight into subsurface conditions.
Testing Methodology
The falling head test is carried out within a borehole that has been installed during site investigation works. The test involves introducing water into the borehole so that a column of water is established above the natural groundwater level.
Once the test begins, the water is allowed to seep into the surrounding soil, causing the water level within the borehole to fall over time. Measurements are taken at set intervals to record the rate at which the water level decreases.
This change in water level is used to calculate the permeability of the soil, providing a quantitative measure of how easily water can move through the ground. The test is carried out in a controlled manner to ensure that results are consistent and reliable.
Relationship to Other Permeability Tests
Falling head testing is one of several methods used to assess soil permeability, alongside rising head and constant head tests. Each method is selected based on the specific ground conditions and the objectives of the investigation.
The falling head test is particularly suited to soils where permeability is relatively low, allowing accurate measurement of how water dissipates over time. By selecting the appropriate testing method, Chelmer ensure that the most relevant data is obtained for each site.
Integration with Site Investigation Works
Falling head tests are typically carried out as part of a broader site investigation programme, often in conjunction with boreholes and groundwater monitoring installations. This integrated approach allows permeability data to be considered alongside other ground and environmental information.
By combining testing with other investigation techniques, Chelmer are able to build a comprehensive understanding of site conditions. This ensures that all relevant factors, including soil properties and groundwater behaviour, are taken into account.
Supporting Groundwater and Drainage Assessment
Permeability testing plays an important role in assessing how water interacts with the ground, which is essential for both drainage design and environmental evaluation. Falling head tests provide the data required to understand subsurface water movement and to design systems that manage this effectively.
The results of testing are incorporated into Chelmer’s reporting process, where they are analysed alongside other site investigation data. This ensures that findings are presented clearly and can be used to support design and decision-making.
Through accurate testing and integrated analysis, Chelmer provide reliable permeability data that supports a wide range of geotechnical and environmental applications.