Abstract:
Every structures and structural activities are performed on geotechnical material called soil or rock. Hence, investigation for these materials is quit important to have durable, cost effective and remain safe design and construction. The main objective of this research is to get reliable results of the engineering properties of residual tropical soils and to understand about the nature of soils so that the suitable foundation can be recommended for better design and construction of civil engineering works in the town. To do so, field and laboratory activities performed as per according to ASTM standard. As per findings, these soils are mostly white brown as per visual observation. Soils are more in clayey-sandy soils with some of low plastic inorganic clays which are non-expansive.
In-situ moisture content results ranged within 10.84% to 24.16% which increases with increase in depth of sampling for study area. Specific gravity of soils determined values fell within a range 2.55 to 2.75. It was observed that the specific gravities of the oven dried soils results are greater than results of air dried soli specimens in one soil sample. The grain size analysis results indicate that the dominant proportion of particle in the study area is more in coarser/sandy soils, except test pits TP5, TP6 and TP7 all soils retained more than 50% through sieve size 0.075mm., which confirms soils of study area is dominated by coarser soils. But almost soil grains are passed sieve size 4.75mm; hence soil grains are governed by sandy soils. As per consistency limit investigation, soils found in Jinka town are low in plasticity having liquid limit less than 50% and plastic index less than 30%. The free swell of the soil under investigation ranged from 5% to 23%. As per USCS soil classification, Jinka town soils are categorized in to three groups. These are SM, SC and CL soils having MDD ranges 1.38 to 1.73 g/cm3 whereas OMC ranges 11.22 to 22.80 %. Direct shear test results shear parameters cohesion 3.22 kpa to 13.44 kpa and angle of friction of 22.330 to 33.260. Whereas undrained shear strength from unconfined compression test of the study area for TP5 and TP6 are 120.24 kpa and 160.33kpa respectively. The values of the compression indices Cc is 0.127 and 0.146 whereas recompression indices is 0.013 and 0.015 for TP5 and TP6 respectively
