EMS Geotech have equipment and experienced geotechnical engineers able to undertake various forms of in-situ strength testing. In-situ strength testing is typically recommended or required during project planning, temporary works or earthworks verification. EMS offer a range of in-situ strength testing including:. Such tests are typically used to determine the physical properties of formations or subgrades, placed capping layers and sub-base.
It was first developed by the California State Highway Department. It is a penetration or settlement under load test which is used to evaluate the subgrade strength primarily of roads, pavements and foundations. The CBR test often forms part of the overall site investigation and is useful for determining the thickness of materials needed for the proposed construction. The CBR test can be carried out in soils with a maximum particle size pf 20mm. Plate Bearing tests would be recommended where particle size exceed 20mm diameter.
Tests are usually undertaken at surface level or at depths of between m, most commonly in m intervals along the proposed construction centreline. A CBR Test works by testing the pressure required to penetrate a soil sample with a plunger of the standard area and measuring this. This measurement is divided by the pressure needed to achieve an equal penetration on a standard, high quality crushed rock material.
The harder the surface, the higher the CBR value. The CBR test can be carried out on soils with a maximum particle size of 20mm. Tests are most usually undertaken at surface level or at depths of between m, most commonly in mm intervals along the proposed construction centreline. On a typical site with prepared surfaces, multiple CBR tests are usually undertaken in a day by a single operator. Provisional results are often available on site. CBR testing is undertaken for the design of highways and housing estate roads to determine the strength of the subgrade soil and enable appropriate selection of suitable pavement thickness for the anticipated traffic density together with any precautions for frost heave.
They come in the form of traditional shallow spread foundations strips, pads and rafts or deep foundations piles and ground improvement. The main factors influencing foundation design is the stability of the underlying ground and settlement.
