The undisturbed sample is obtained from pits and boreholes in such a manner that moisture content and structure do not get altered. This may be attained by careful protection, packing, and by the use of a correctly designed sampler.
The sampling shall be done with the help of a sampling tube. The tube sample is generally collected in all kinds of soil except clean sand and gravel. The tube sampler should be lightly oiled or greased inside and outside to reduce friction. It should then be attached to the boring rods and lowered to the bottom of the borehole or trial pit. The sampler should be pushed down into the soil by hand or by jacking; alternatively, the sampler may be driven by blows from a ‘monkey’.
