Test pits, trenches, shafts and tunnels are the direct excavation methods of exploration which not only affords sampling and testing in situ but also permit visual inspection of the soil and rock formations in their natural state. They are considered the only means of obtaining reliable information in a soil deposit of mixed sand, gravel and boulders where boring may prove difficult. However, they are slow and become relatively expensive with increasing depths of exploration.

Trial pits are the cheapest way of site exploration & do not require any specialized equipment. A pit is manually excavated to get an indication of the soil classification & obtain undisturbed & disturbed samples. Trial pits allow visual inspection of any change of strata & facilitate in-situ testing. They are suitable for exploration of shallow depth only.