Correlation among Index Properties, Strength and Compressibility Parameters of Peat Soils in Muthurajawela Region of Sri Lanka

Peat is an extreme form of soft soil and its geotechnical properties cannot be determined so easily as it is waterlogged most of the time. Developing correlations among different properties of peat will enable study of geotechnical properties of peat. Hence, aim of this paper was to develop correlations among index properties, unconfined compressive strength (UCS) and compressibility parameters of some peat soils collected from Muthurajawela region, Sri Lanka. Fifteen disturbed and undisturbed samples were collected and index property, UCS and 1-D consolidation tests were conducted for all the samples. Seven correlations were developed based on the experimental results and it was noted that the correlations developed were consistent with similar correlations reported in the literature. The results show that the liquid limit (LL) of peat increases with organic content (OC) and water content (WC). In addition, both the specific gravity (Gs) and UCS values reduce with increase in OC value. When the WC increases, the UCS of peat tends to reduce as the water holding capacity of peat increases with the increase in WC. The compression index (Cc) reduces with the increase in LL and it is due to the increase in compressibility with the increase in LL. The findings of this study revealed that geotechnical engineers can refer to these correlations to study the preliminary behavior of peat soils in Muthurajawela region, where geotechnical data is not readily available.