Role Of Clays Addition On The Stability Of Collapsible Soil Selected From Mosul City

AbstractVolume changes of a collapsible soil selected from Hawy Al-Kanissa inMosul city were studied. The Influence of addition of (5, 15 and 30) % of low (CL)and highly plastic (CH) clayey soil were studied. Many variables as: the initial dryunit weight, water content and applied stresses on volume change were considered.State diagrams representing gradual volume change due to these variables were alsopresented and discussed.The main results were showed that the collapse potential (Cp) increasedcontinuously for samples mixed with (CL) soil while there were a maximum value at(5%) of (CH) soil. At low unit weight, (Cp) for samples mixed with (CL) reached ahighest value at certain stress, then started to decrease, while it increasedcontinuously using (CH). (Cp) of soils containing (CH) was found to be less than thatmixed with (CL) soil. Concerning soil volumetric changes using state diagramspresentation, volume change for undisturbed natural soil at low moisture content wasfound less than that in disturbed samples, but the inverse was obtained at saturation.Besides that, volume changes increased with the increase of the clay additive indifferent manner for (CL) and (CH) soils.Keywords: Clay, Collapsible soil, Volume change, unsaturated soil.