Soil Investigation Report

(Remark: The followings are my notes after reading relevant papers for civil engineering works. It is posted online for my ease of reference and whoever may need a glimpse on the subject.)

Moisture Content, Wn




Liquid Limit, LL



Presence of sand/ silt reduce LL.


Wn=LL mean soil is normally consolidated, Wn>LL mean soil is very soft like liquid.




Plastic Limit, PL



High content of clay, high value of PL. Sand have no PL.


Wn=PL mean soil is over-consolidated. 




Plastic Index, PI = LL-PL



Amount of clay present. High PI=high clay content, high plasticity, high compressible, greater volume change characteristic.





Specific Gravity



SG=2.65 (normal inorganic soil)



SG<2.65 (w. organic material)



SG>2.80 (w. metal content likes iron oxides.



SG (for use of calc of void ratio in consolidation test, compaction test.)