Consolidation by Sand Drains in Initial Gradient Soils

Phenomenon of water movement through cohesive soils is important to several fields of engineering. Many investigations on flow through such soils indicate that seepage starts only when the hydraulic gradient exceeds a certain value called the initial or threshold gradient and the velocity gradient. In the absence of the initial gradient, theoretical solutions for radial flow towards sand drains exits. In this note an analytical solution is presented that incorporates the concept of initial gradient to the problem of radial flow to sand drains. The solution is based on the assumptions of equal strain, no smear, constant compressibility and permeability, and time independent external load.