Theoretical Simulation of Experimental Results with Barron’s Theory for Consolidation of Soft Clay by Radial Flow Using PVD

Abstract

AbstractThe rapid development and associated urbanization have compelled engineers to construct earth structures, including major highways, over soft clay deposits of low bearing capacity coupled with excessive settlement characteristics. Consolidation due to radial drainage using PVD is one of the ground improvement techniques in which the consolidation is accelerated by reducing drainage path. Soil improvement is required to provide adequate bearing capacity and improve shear strength of the soft cohesive soils to satisfy the need for various type of construction on sites underlain by such soft soils. Among various ground improvement techniques the technique of preloading or pre-compression used in combination with vertical drains is one of the oldest and most widely used techniques to preconsolidate and strengthen weak compressible soils. Present research work presents experimental model of various drain material to expedite the in-situ settlement due to excess pore water pressure dissipation under preloading by radial drainage taking advantage of having more horizontal permeability than vertical. The hydraulically pressurized Rowe Type Oedometer was developed in the applied mechanics department of The M.S. University of Baroda, India. The present research work focuses on finding most optimum drain in terms of materials (both natural and synthetic type), size (diameter of drain), and geometry to accelerate consolidation of soft clays with a complete set-up of hydraulically pressurized modified oedometer with conventional bishop pore pressure measuring system and measuring settlement with dial gauge. The effect of PVD of ‘n’ value (ratio of zone of influence to the diameter of drain) of 10, n = 12.09, n = 14.76 on consolidation characteristics of Kaolinitic clay were undertaken to investigate the dissipation characteristics using isochrones and settlement characteristics. Time-pore pressure dissipation and time-settlement observations were recorded for different applied stress under long duration test. Average degree of consolidation was computed using isochrones. Barron’s equal vertical strain theory with no smear and no well resistance has been used to carry out the analysis for radial consolidation. Present work shows the comparison of experimental results with Barron’s theoretical curve with all the drain materials.KeywordsBarron’s theoryFree and fixed vertical strain theoryCo-efficient of consolidation due to radial flowTime factor