3D Analysis of Improved Soft Ground with a Group of Floating of Stone Columns Laid on the Appropriate Bed

One of the proper methods to improve the soft and loose ground is the use of stone columns. High shear strength and low compressibility materials substituted for soft and loose soils with low shear strength and increased compressibility will transfer a significant part of the loads applied to the foundation in the soil and stone columns will improve the soil. The investigation of the previous studies has revealed that most of the numerical analyses are conducted in 2D forms by the equivalence of stone columns or a single cell. Therefore, the numerical analysis of improved soft-ground with stone columns has been investigated using the finite element PLAXIS 3D software. To this end, four layouts of stone column group were used under the foundation with various numbers of columns of 4, 9, 16 and 25. The depth of improvement was considered 6m and 10m for floating and laid on a suitable bed, respectively. The results of decreasing the percentage of a ground settlement for various groups of stone columns and improvement depths of 6m and 10m were in the ranges of 15-49% and 17-63%, respectively. Besides, the shear strain distribution and the amount of stress decreased due to the increase in the number of columns. At the end, a design diagram was presented to examine the reduction of the ground settlement in two improvement modes with an improvement depth of 6 m and 10 m compared with the unimproved ground.