Direct methods of exploration:
Following are some of the direct methods of exploration:
- Test pits, Trenches, Shafts, Tunnels.
- Probing and sounding.
- Test boreholes.
- Test pits, Trenches, Shafts, Tunnels:
This method is also known as open excavation method. It is one of the most satisfactory methods of soil inspection by visual observation and it also provides both disturbed and undisturbed sampling. It can be done manually by hand, using labor, or by using some equipments like backhoe, trencher or the dozer etc. test pits are used for exploring sites where greater sampling is required such as highways and airfields.
- Probing or sounding:
A steel rod of about 25 mm diameter is driven into the ground for the purpose of probing and sounding. The deriving resistance to rod and the adhering particles to the rod when it is pulled out, tells us type and properties of soil.