Ventilated Well Method for Efficient Dewatering of Soft Soils: Dimensional Analysis and Validation through Numerical Modeling

Abstract

The ventilated well method (VWM) is a recently introduced novel dewatering and densification technique for soft soils that relies on controlled evaporation through ventilated and perforated wells traversing through the soil deposit. Several parameters, including geometry of the ventilated well, geometry of the testing mold, soil properties, and properties of the input air, govern the efficacy of the VWM. In this paper, a dimensional analysis (DA)–based approach, following Buckingham’s pi theorem, is used to derive the dimensionless π groups for the VWM problem. Using the experimental results from the laboratory-scale implementation of the VWM and multiple regression analysis, a simple dimensionless model between the π groups is suggested. The analysis revealed that, keeping the rest of the parameters constant, the dewatering rate increases with an increase in well diameter, air flow rate, and hydraulic conductivity of soil. However, it decreases with an increase in well height, mold diameter and osmotic suction of the pore fluid. A sensitivity analysis was also performed to understand the relative dependence of the dimensionless dewatering factor on the variation of the four other dimensionless input parameters capturing the influence of the well geometry, mold geometry, soil property, and flow property. Finally, the results from the DA-based model were compared with that obtained from a numerical model, and a good degree of agreement was observed. It is envisaged that both the DA-based model and the numerical model will be useful for scaling the VWM for future experimental work, pilot studies, and field trials.