Radial consolidation equation with variable load, material and drain efficiency parameters

Numerous complex analytical solutions are available for analysis of consolidation problems involving radial drainage, yet the most common solution used for determining the rate of consolidation is the equal strain solution presented by Hansbo (1981). Maintaining the simplicity of Hansbo’s (1981) solution this paper presents radial consolidation equations that capture the versatility of the more complex methods. Material and geometry properties vary piecewise-constant with time while loading/unloading varies piecewise-linear with time. A new drain efficiency parameter is introduced to model the detrimental effects of drain clogging and kinking. Drain clogging/kinking is simulated by specifying the excess pore pressure in the drain, normally set to zero, as a fraction of the average excess pore pressure in the soil. The new equations are easily implemented in a spreadsheet or computer program providing a simple yet versatile tool for analysis of consolidation problems dominated by radial drainage. Computer code for implementing the new approach in a Microsoft Excel is provided.