Sustainable development of infrastructure is a key to planned urban environments in more modern global economies driven by industrialization. For efficient management of design and construction of such infrastructure projects, prior assessment of geotechnical property variations is valuable and could drive to reduce number of field and laboratory tests. Our study aims at assessing geotechnical relationships for residual, alluvial, marshy, coastal, and compacted soils within the wet and the dry zones of Sri Lanka. Plastic limit (PL), liquid limit (LL), shrinkage limit (SL), plasticity index (PI), liquidity index (LI), compression index (Cc), swell potential (SP), activity, natural moisture content (NMC) and SPT-N values, were either extracted from reports or deduced from formulas and graphs. Wet zone Marshy soils (My_W) show highest statistical means for PL(23.43%), LL(39.90%), PI(15.60%), SL(19.50%), LI(0.96), Cc(0.210) and NMC(35.16%), representing poor engineering properties. Whereas, wet zone residual soils (Re_W) represent wide range with direct correlation to the parent material. CH, OH, CL and SM soil groups for some My_W display high expansive, while, CL, Pt/CL, OL, SC, SM in My_W, CL and SC in Re_W and CL in Dry Zone Alluvial Soils (Al_D) are medium expansive. The higher SPT-N values were recorded in the upper 6.00m and between 12.00-16.00m for Shell of Dry Zone Earth Dams (SED_D), whereas Al_D represent higher N values for 6.00-12.00m zone. Except for marshy soils, no vertical variation for plasticity was observed. Since high to medium swell potential and unsaturated zone are encountered within the upper 1.50m, attention should pay to the My_W. LL and PI of My_W were strongly correlated (R2 = 0.83) so that PI% = -1.91 + (0.46*LL%) could be used to calculate PI. The results provide baseline geotechnical property variations for the five soils, so that planning could be improved and time and cost for investigations could be cut down.
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