| |
|
| 4 |
In-situ tests |
|
General |
| |
The in situ tests in the field have the advantage of testing the soils in their natural, undisturbed condition. Laboratory tests, on the other hand, make use of small size samples obtained from boreholes through samplers and therefore the reliability of these depends on the quality of the so called ‘undisturbed' samples. Further, obtaining undisturbed samples from non-cohesive, granular soils is not easy, if not impossible. Therefore, it is common practice to rely more on laboratory tests where cohesive soils are concerned. Further, in such soils, the field tests being short duration tests, fail to yield meaningful consolidation settlement data in any case. Where the subsoil strata are essentially non-cohesive in character, the bias is most definitely towards field tests. The data from field tests is used in empirical, but time-tested correlations to predict settlement of foundations. The field tests commonly used in subsurface investigation are: |
 |
Penetrometer test |
|
Pressuremeter test |
|
Vane shear test |
|
Plate load test |
|
Geophysical methods |
 |
|
Penetrometer Tests : |
|
Standard penetration test (SPT) |
|
Static cone penetration test (CPT) |
|
Dynamic cone penetration test (DCPT) |
| |
|
