اعلام المكتبة المركزية / المهندس مهند
Abstract
Soft soil is described as being very compressible or sensitive to excessive water infiltration due to its density or composition, the properties of soft clay can undergo extreme changes, for example, high settlement, shrinkage, swelling, and low shear strength. There are many techniques used to treat soft clay soils such as pre-loading, mechanical compaction, granular columns, and electroosmosis technique. Granular columns are vertical columns of compacted aggregate or sand that are generated through improved soils. In this study, soft soil improved by column and numerical model used Finite Element Model (FEM) to study the behavior of settlement of soft clay soil. Soil has dimensions (L=6 m) with (D=8 m) depth. Granular columns with various depths (4,6, and 8 meters) and diameters (0.5,0.8,and1m) are used to treat weak soil. The behavior of settlement is investigated during a period of 180 days. The electric model is applied to use as a second technique with various voltages (5,15, and 30 volt) to study the effect of electric current on the surface settlement and pore water pressure of soft soil treated with granular columns and electric current together.
The findings demonstrate that the improvement ratios of soft soil treated by granular columns for optimal ratio (L/D=8) with load (36 kN/m2) reach (35%) and that it reaches (50%) and (72%), respectively, when an electric current is supplied from (5-15 volt).
The pore water pressure reaches its highest value at (35 days) and then begins to decrease gradually until it reaches zero at 180 days, for the best ratio of (L/D=8).
The soft soil is treated by granular columns only, PWP reaches to a high value and when shedding an electric current with a voltage of (5-15 volt) the drainage path reduces from the soil is treated with columns only, and when voltage increases (15-30 volt) the drainage path became shorter due to electric field while the exit of water from the soil became faster.
When increasing the load to (72 kN/m²), the improvement percentage for soil containing granular column reaches to (50%) and when applying an electric current with (15-30 volt) it reaches to (87%), the PWP for the same load increase more than the previous load to resist the imposed load, it reaches to the highest value and then presses to release water from it, and its value decreases until becomes zero when applied a stress of (108 kN/m²), the degree of improvement for the soil treated with granular columns reached (60%) and (92%) when applied electric current with (15-30 volt).
