Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Soft soil

Influence of Fly Ash Addition on Behavior of Soft Clayey Soil

Hussein H. Karim; Zeena W. Samueel; Adel H. Jassem

Engineering and Technology Journal, 2020, Volume 38, Issue 5, Pages 698-706
DOI: 10.30684/etj.v38i5A.426

This paper investigates the impact of the fly Ash addition on the Geotechnical properties of soft soil as well as chooses the optimum percentage added of fly ash. To understand the behavior of fly ash mixed with soil, a number of laboratory experiments testing conducted on clayey soil-fly ash mixture in several percentages (5,10,15,20,25, and 30%) as Atterberg test, Specific gravity test, compaction test, California Bearing Ratio (C.B.R) Test, Unconfined Compressive Strength (UCS) Test, Consolidation Test. Test results indicate rising in plastic limit and liquid limit as fly ash adding. Specific gravity decreased essentially by adding fly ash. Whereas there was falling on the Dry unit weight value with the contract to the decreasing in the water content. The CBR and UCS values were increased with increasing fly ash content. 20% was the optimum fly Ash content. This study also benefits the effective use of fly ash and thus a cost-effective method for improving the soil properties.

Sand Column Stabilized by Silica Fume Embedded in Soft Soil

Hussein H. Karim; Zeena W. Samueel; Mohammed S. Mohammed

Engineering and Technology Journal, 2016, Volume 34, Issue 6, Pages 1047-1057

This research aims to study the behavior of the sand columns stabilized with silica fume (as an additive with different percentages) and driven in soft soil bed with undrained shear strength (cu) between 16 – 21 kPa. Holesin the shape of columns with diameter 50 mm and length 300 mm have been drilled in a soil bed and backfilled with sand mixed with several proportions of silica fume with 7-days curing. A rigid circular footing with diameter 64.6 mm was located on each column and loaded axially till failure. The results analysis of the model tests indicated an encouraging improvement in load carrying capacity of the columns and considerable reduction in the settlement compared to the conventional stone columns. The bearing improvement ratio and settlement reduction ratio exhibited by the sand columns are 1.18 and 0.71, respectively. The best possible addition of silica fume content in sand–silica fume columns is 7% giving bearing improvement ratio and settlement reduction ratio of 1.56 and 0.5 respectively.