Permeability and pumping tests

The coefficient of permeability, which shows how quickly soil transmits water, is the key parameter for drainage, dewatering, excavation and water well calculations. It can be roughly taken from tables, but in real ground the value may differ many times even within one soil type. A wrong parameter leads either to drainage that fails or to an unnecessarily powerful and expensive pumping system.

In a pumping test water is extracted from a central well at a constant rate while drawdown and recovery are measured regularly in it and in surrounding observation wells. The results allow calculation of hydraulic conductivity, transmissivity and the radius of influence. In unsaturated or low-yield soils falling-head and injection tests are performed instead.

Measurements are made with electronic water level loggers and flow meters, and data is processed using standard analytical methods. The test layout depends on the project: a single-well test suits small sites, while a cluster test with observation wells is better for large excavations and water supply projects.

Since groundwater is shallow on many construction sites in Baku, correct design of dewatering for deep excavations affects both safety and the stability of neighbouring buildings. Tests are carried out in line with the applicable codes (AzDTN/SNiP).

When you need it

• Dewatering design for deep excavations
• Drainage system calculations
• Determining water well yield
• Design of stormwater and wastewater infiltration
• Assessing groundwater inflow beneath buildings

What's included

• Selection of the test layout
• Preparation of test and observation wells
• Pumping test
• Falling-head and injection tests
• Drawdown and recovery measurements
• Calculation of hydraulic parameters
• Water sampling

How we work

1. Analysis of geological data
2. Preparing the test programme
3. Well installation and equipment set-up
4. Testing and measurements
5. Data processing and report

Deliverables

• Technical test report
• Drawdown and recovery graphs
• Hydraulic conductivity, transmissivity and radius of influence
• Recommendations for drainage and dewatering