In Situ Testing
CBR (CALIFORNIA BEARING RATIO) TESTING
A CBR test is usually used for road design purposes. It involves driving a cylindrical plunger which has a defined area into the soil at a uniform rate of 1mm per minute, at a depth of between 500 – 1000mm. This requires the use of a reaction load (usually ba 4WD drive vehicle) to provide the force to the plunger and CBR press.
Clegg testing can be used as a means of indirectly determining CBR values for pavement design. This works by using the impact of a hammer which simultaneously causes an electronic output to a digital display. The output is based on the peak deceleration of the hammer’s impact with the surface. Four successive blows of the hammer on the same spot constitutes one test, called a Clegg Impact Test (CIT). The CIT provides a soil strength/stiffness – or “hardness” – parameter known commonly as Clegg Impact Value (CIV).
STANDARD PENETRATION TEST (SPT’S)
All our drilling rig SPT hammers are calibrated to the standard BS EN ISO 22476-3:2005+A1:2011
AUTOMATED SOAKAGE TO BRE365 AND DEEP BOREHOLE SOAKAWAYS
Soakaway dissipation tests can either be carried out by the BRE365 pit test or less accurately but more cost effectively by using deep borehole soakaway tests (also known as falling head test), as part of the site investigation drilling programme. Our engineers can consult with you as to the nature of your project, to determine which method is the most suitable.
PLATE BEARING TESTS
This is a method used to estimate the bearing capacity of a soil. A rigid steel plate between 300 to 600mm square is placed at foundation level and then loaded until the foundation fails; the maximum bearing pressure is shown by the rapid deflection (sinking) of the plate.