A soil investigation report should contain the data obtained from the boreholes, site observations & laboratory results. It should also give the recommendations about the suitable type of foundation, allowable soil pressure & expected settlements.

It is essential to give a complete and accurate record of data collected. Each borehole should be identified by a code number. The location of each borehole should be fixed by measurement of its distance or angles from some permanent feature. All relevant data for the borehole is recorded in a boring log.

A boring log gives the description or classification of various strata encountered at different depths. Any additional information that is obtained in the field, such as soil consistency, unconfined compression strength, standard penetration test, is also indicated on the boring log. It should also show the water table. If the laboratory tests have been conducted, the information about index properties, compressibility, shear strength, permeability etc. should also be provided.

he data obtained from a series of boreholes is presented in the form of a sub-surface profile. A subsurface profile is a vertical section through the ground along the line of exploration. It indicates the boundaries of different strata along with their classification. It is important to remember that conditions between boreholes are estimated by interpolation, which may not be correct. Obviously the larger the no. of the boreholes, the more accurate is the sub-surface profile.

The site investigation report should contain the discussion of the results. The discussion should be clear & concise. The recommendations about the type & depth of foundation, allowable soil pressure & expected settlements should be specific. The main findings of the report are given in conclusions.