Expediting the Consolidation of Clayey Soils Utilizing Microwaves

Post-construction settlement has been an issue in the field of construction due to the excessive time taken for the dissipation of pore water pressure. This is significant for construction carried out on clayey soils primarily due to the low permeability of clayey soils. Therefore, attention has been directed at finding means of increasing the rate of pre-consolidation. Recent research has focused on the effects of temperature on consolidation. It has been shown that elevated temperature increases the hydraulic conductivity of pore water due to both the reduction of viscosity and differential volumetric expansion of soil and water. This results in an increase in the rate of pore pressure dissipation. In addition, it has been proven that compressibility properties also improved at elevated temperature and subsequently, the rate of consolidation of the clay. This research aimed to study the feasibility of utilizing microwaves to expedite the aforementioned temperature elevation and the subsequent consolidation of a clay soil. A numerical model has been formulated using finite difference methods to theoretically predict the temperature rise and pore pressure dissipation. The results of the numerical model proved to be in general agreement with the experimental data. The feasibility of utilizing microwaves to raise the temperature of the soil sample was also evaluated practically by conducting bench-scale experiments. The use of microwave irradiation to rapidly increase the temperature of saturated clay was quantified by this research and was proven to be more efficient than currently used soil heating methodologies. Comparable consolidation experiments showed that increasing the temperature of the sample using microwave heating resulted in a higher rate of settlement when compared with the settlement of the non-heated sample while the ultimate percentage settlement of both were equal