Selection of Best Fit Correlation for Compression Index of Soil from District Bannu

Geotechnical investigation is one of the major steps in the safe and economic design of foundation for any structure. This requires some soil parameters to be established. CI (Compression Index) is one of these parameters. The stability of a foundation is not fully justified as long as the magnitude of settlement is unknown. The problem arises when the value of CI is needed badly and a consolidation test is set up for this purpose which consumes almost 3 days for its completion provided that the assembly would not be disturbed. Little amount of disturbance can cause serious error in further calculations and plotting of data. Undisturbed soil sample is the primary demand of consolidation test which is a tough job for a person having not been experienced very much in the fieldwork. In order to overcome these complexities, the researchers have established various correlations between compression index and some basic soil properties like Atterberg limits, void ratio, natural moisture content and OMC (Open Moisture Content), as they are simple to be determined and takes small amount of time. This research has been conducted on soil samples collected from a single spot at an interval of 5ft depth for the sake of validation of a suitable correlation for Bannu District, KPK (Khyber Pakhtunkhwa), Pakistan so that the determination of compression index becomes simple and convenient.