Permeability Studies in Marine Clays Stabilized with Lime Column

Soft marine clays are very sensitive to changes in the stress system, moisture content and system chemistry of the pore fluid. Geotechnical engineers feel a necessity to improve the behavior of these deposits using anyone of the available ground improvement techniques. In the present investigation an attempt has been made to improve the permeability of a marine clay using the lime column technique. The experimental program was carried out with model lime columns installed in two test setups. In the first setup, a single lime column was installed in the center of a circular tank. Having established the diffusion of lime from the single lime column setup, tests were carried out in the second stage with a lime column group installed in a rectangular tank to study the interaction of lime columns. A marine clay from the east coast of India was used for all the tests. A number of samples were collected from all the setups at different radial distances from the lime columns and at varying time periods. From the tests carried out using these samples, it has been established that the lime diffused into the surrounding soil for large distances; this is indicated by an improvement in pH values. Reaction products formed as a result of reaction between lime and clay were identified by the X-ray Diffraction (XRD) technique. Permeability (k) values show an enormous improvement and the k values were improved up to 23 times. This shows good promise for improving the soft coastal deposits and the offshore deposits.