BEARING CAPACITY OF STRIP FOOTING RESTING ON DUNE SANDS STABILIZED BY GROUTING WITH LIME?SILICA FUME MIX

Extensive dune sand deposits cover specific areas of Iraq. Dune sands are often an environment hazard during strong winds and sand storms particularly in the summer months. A little research has taken place to study the characteristics and the behavior of dune sands. An extensive laboratory testing program was carried out to study the geotechnical properties and the behavior of dune sands. The tests include moisture content, classification, compaction, relative density, direct shear, chemical tests. Also, loading tests were carried out on footing model of strip shape (3.2 × 33) cm rested on natural dune sand. The effectiveness of adding different percentages of lime-silica fume mix was studied. Silica fume (SF) and lime-silica fume (L-SF) mix has been used for stabilizing and considering their effects on the dune sands. The improvement technique adopted in this study represents an attempt to stabilize the dune sands by grouting the soil by a slurry of lime-silica fume material with water. For grouting the dune sands around the stabilized area, a 1000 ml grout pump was used as a liquid tank of the lime-silica fume mix and the maximum pressure which can be applied by pumping the grout into the dune sands with the help of a grout pump is about 25 kPa.