Effect of Soil Nailing on Some Problematic Soils


The land scape is subjected to higher temperature during the last three decades became of "Globule warming", which became high evaporation of surface water, in addition to the increase in salt content , because of the unaffected irrigation way, of planets and the increase in the capillarity action which contribute with this process. This may led to the dissolution of salts inside soil and its appearance on the ground surface, with different depths. The NaCl salt is one of the most common salts presence in widely areas in Iraq, which has high dissolution rate in water. The problem of such soils appear when subjected to miniaturization from any source, resulting high dissolution rate of the salts in side soil skeleton, which lead to the weakening of soil, cavities may appear inside soil layer, and so it may led to failure of structures constructed on it.This study includes the feasibility of improving the collapsibility of natural saline soil with 10% salt percent, brought from, Jurf Al-Milih region in Diyala Governorate, by mixing it with randomly distributed nail reinforcement, with three different lengths "Ln", related to width of footing "B" , (Ln/B=11%, 14.2% and 21.4%). By carrying settlement test for single model footing with time, for treated and untreated model using this technique at both dry and wetting conditions, using locally manufactured Laboratory model. This technique reduce the collapsibility of such soil, 27%.The study includes also the effect of mixing the saline soil with some available additives: (1.5% and 3%) Lime material, (2% and 5%) of Cement material, with and without reinforcement. and investigates its effects on the collapsibility of such problematic collapsible soil. The best improvement was achieved by mixing the saline soil with (5% cement, and randomly distributed reinforcement using Ln/B=14.2%). this will reduce the collapsibility of such problematic soil, 90%.The best treatment used in this study, is by mixing the saline soil with natural and available material which is Bentonite, with two percentages (5% and 10%) without reinforcement. and the improvement achieved by mixing saline soil with 10% Bentonite. This reduces the collapsibility to 97%, when wetting such soil with water. So it may consider the most effective treatment technique used for such soil.