BEARING CAPACITY OF FOUNDATION ON SOIL STABILIZED BY DEEP SUSTAINABLE -IMPROVEMENT
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Date
2024-10-25
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Abstract
ABSTRACT
Weak soils, such as loose sand, have high compressibility and low
shear strength. Construction on weak soils often requires utilization of
ground improvement techniques. However, cement and lime, which are
the most common used binder, are the major contributor of CO2 and have
sever impacts on the environment. Recently, the construction industry
immense pressure to come up with materials and processes that are ecofriendlyand promote sustainable development. Therefore, this research
deals with improving the performance of the weak soil in term of
increasing it strength using sustainable materials.
Two approaches have been employed in this study. The first one dealt
with investigating the performance of soil improved by (cement kiln dust,
calcined clay, and alkali activator) considering various percentages of
Alkali material and activator ratios. While the other approach investigated
the using of such sustainable materials as a binder to improve the bearing
capacity of the soil by the deep mixed columns, experimentally and
numerically.The first approach showed increasing the unconfined compressionstrength of the soil with increasing the Alkali material, cement kiln dust,for all the activator ratios. Cement kiln dust-soil Alkali of 0.4 MPa
compared with 0.0167MPa of the untreated soil. Incorporating the
calcined clay, which is an alumina-silicate enriched material,
consequence of pronounce improvement, where the strength increased
drastically to about 3.57MPa when calcined clay/Alkali material= 0.5.
Regarding the activator ratio, the optimum ratio necessary to activate the
inert cement kiln dust and calcined clay is 0.5, beyond that there is a slow
increase or decrease in the strength, depending on the Alkali material
content.In the second approach, tests performed using pilot field models, the
diameter of column = 15cm and its height = 150cm, revealed clearenhancing of the performance of footing resting on soil reinforced by
deep sustainable mixed columns. Compared with bearing capacity ofunreinforced soil of 88 kPa, the bearing capacity of square footing (B =
75cm) increased by 50, 126, 223, 243, 338, 324, 328, 365, and 385%corresponding to reinforcing the soil with 1, 2, 4, 6, 8, 10, 12, 16 and 20
deep soil mixing columns, respectively. However, when the load was applied on the column only and not the surrounding soil, the bearingcapacity was 16 times that of the untreated soil. The results of this
approach were verified numerically using PLAXIS 3D software.