CENTRIFUGE MODELLING OF PERMEABILITY OF SOILS
Hydraulic conductivity of geomaterials is an important parameter involved in assessment of ground water advection, migration of contaminants in the subsurface and for the design of barriers to contain hazardous wastes. This requires establishing a methodology for estimating hydraulic conductivity of these materials using 1-g laboratory tests. Evaluation of hydraulic conductivity of soils by employing geotechnical centrifuge, where centrifugal acceleration is used to simulate the prototype conditions, is an area of current research interest.
In this dissertation an effort has been made to study the hydraulic conductivity of a silty-sand and marine clay, compacted to different compaction states, using conventional 1-g and centrifuge tests and the results have been used to derive the scaling relationship for hydraulic conductivity of soils. Various 1-g tests involved in the study are; conventional falling-head tests, oedometer falling-head tests and the oedometer consolidation tests. It has been shown that the scaling relationship for permeability can be modelled adequately in a centrifuge as per the theoretical scaling laws derived by the earlier researchers. Relationships have been established to demonstrate variation of soil hydraulic conductivity with respect to its void ratio, the moulding moisture content, the applied pressure and the centrifugal acceleration.
Artificial Neural Networks (ANN) have been trained and tested, based on various parameters influencing the hydraulic conductivity, to estimate soil hydraulic conductivity. A comparison of ANN predictions vis-a-vis experimental observations indicates the efficiency of the networks.
|
