Efficient Method to Model the Consolidation of Multilayered Soil System with Horizontal Drainage Pipes

Abstract

Horizontal drains can effectively accelerate the consolidation of soils. In this study, an analytical model for the consolidation of a multilayered soil system with horizontal drainage pipes is developed first. A virtual semipermeable layer containing the drainage pipes is introduced to simplify the analysis. A semipermeability coefficient (R) is then adopted to describe the drainage capacity of the virtual semipermeable layer. The analytical solution is derived following separation of variables method and Duhamel's principle, which is verified by two existing analytical solutions in literature from different aspects. By comparing the results calculated by the analytical solution and numerical model, an efficient method is proposed to relate the arrangement of drainage pipes and R. The method is effective if the layer thickness is large enough compared with the pipe diameter and the pipe spacing is not too small. Based on the equivalent method, a preliminary design method of the horizontal drainage pipes is also proposed.