Consolidation of soft clays through radial flow using hydraulically pressurized oedometer

Abstract

Experimental modelling of prefabricated vertical geodrains namely sand drains, sandwick, coir-jute drain and polypropylene fibre drain of different size (diameter) is carried out using modified hydraulically pressurised Oedometer through inward radial drainage to evaluate various consolidation parameters. Vertical geodrains of 'n' (ratio of sample diameter to drain diameter) values viz. 11.04, 16.93 and 21.71 are simulated in the laboratory to know efficacy of drains under long term static loadings. Object of the present investigation is to modify existing hydraulically pressurized Oedometer for the measurement of pore water pressure at various radial points to obtain experimental isochrones that is sequence of consolidation and at various ratio of radius of drain to radius of influence for corresponding concentric planar location for given height of sample at that time with reference to various factors like type of drain material, various shapes of the drain with minimum and maximum drainage path,'n'value, various volumetric water index, various horizontal permeability to vertical permeability ratio and stress history influencing consolidation characteristics of Kaolinite clay under different loadings. The experimental results were compared with theoretical solutions developed by the authors. The results show a fair agreement between measured and predicted values for all drains of all 'n' values. It is concluded that pore water pressure dissipation process at various time interval can be better graphed and projected by hydraulically pressurised Oedometer. © Springer-Verlag Berlin Heidelberg 2013.