THE EFFECT OF SOIL IMPROVEMENT PATTERNS USING DEEP CEMENT MIXING (DCM) ON SOFT SOIL SETTLEMENT

Abstract

Soft soil is a type of soil that has high compressibility, very low shear strength, low permeability coefficient, and high compression. Deep cement mixing (DCM) is a method for improving soft soil. In this modeling, the DCM column patterns with the same total volume of work are varied with the aim of knowing which pattern is effective in reducing settlement. The DCM column pattern is modeled into 8 pattern variations in accordance with the provisions of BS EN 14679:2005 by the British Standard Institution. These patterns are rectangular patterns, triangular patterns, line patterns, wall patterns, block patterns, area patterns, lattice patterns, and overlaid column patterns. In this model, 550 cubic meters of volume DCM is modeled as deep as 28 meters. The number of columns and diameter varies with 25 columns with 1 m diameter for rectangular patterns, 22 columns with 1.06 m diameter for triangular patterns, 47 columns with 0.73 m diameter for line patterns, 67 columns with 0.61 m diameter for wall patterns, 61 columns with 0.64 m diameter for block pattern, 149 columns with 0.41 m diameter for area pattern, 265 columns with 0.30 m diameter for lattice pattern and 123 columns with 0.45 m diameter for overlaid pattern. Based on the results of modeling using PLAXIS 3D, it can be concluded that the greatest reduction in settlement and consolidation time occurs in models with lattice patterned DCM, which can reduce settlement up to 97.45% and reduce consolidation time up to 89.60%.