MS in Civil Engineering (M.S.C.E.)
Degree Granting Department
Civil and Environmental Engineering
Manjriker Gunaratne, Ph.D.
Gray Mullins, Ph.D.
Andres Tejada-Martinez, Ph.D.
Vertical Drains, Settlement, Thermal Yielding, Soft Ground Improvement, Thermoplasticity
Construction in soft soils has been a challenging task for engineers due to the excessive time taken for dissipation of construction induced pore water pressure and the ensuing postconstruction settlement. Use of vertical drains has proven to be an effective and economical method for soft ground improvement and hence extensive research has been carried out to further improve its efficiency. Effect of temperature on radial consolidation is one aspect of such research among many others that have been pursued.
Elevated temperature certainly has a pronounced effect on the hydraulic conductivity due to the reduction it causes in the viscosity of water. Furthermore, temperature also generates excess pore water pressure due to the tendency for differential volumetric expansion between the soil grains and pore water. Thermally induced volumetric strains can have an effect on the magnitude of settlement as well. A numerical methodology based on the NavierStokes equations of flow and thermoelasto-plastic soil compressibility relationships was developed to model transient fluid flow in a clay under thermal treatment. Experimentally verified soil compressibility relationships coupling the loading and thermal effects obtained from literature were employed in this model. The transient temperature distribution within the consolidation soil was modeled using the Fourier’s equation of heat transfer.
The effect of temperature on consolidation of clay was investigated by a parametric study involving different maximum temperatures, surcharge loads and initial porosities of clay. It was concluded that the improvement in the magnitude and rate of settlement at elevated temperature is more significant at relatively smaller surcharges and low initial porosities. Since there is a possibility for thermally induced volumetric expansion even in normally consolidated clays, an optimum combination of surcharge and thermal treatment should be employed for given initial conditions of the soil, in order to achieve the maximum improvement in settlement. The developed numerical model will provide the framework to carry out further investigations and determine the viability of the practical implementation of coupled thermomechanical consolidation using prefabricated vertical drains.
Scholar Commons Citation
Abeysiridara Samarakoon, Radhavi, "Computational Code for Optimization of Thermal Treatment of Fine Grained Soils as a Method of Expediting their Load Induced Consolidation" (2016). Graduate Theses and Dissertations.