Development of a numerical algorithm for a consolidation problem due to subsidence in deep alluvial soils

Settlement of the ground surface due to ground water withdrawal from thick underlyingaquifers may cause serious and costly damage problems.In this study, a land subsidence problem in İzmir Atatürk Organized Industrial Zone(IAOIZ) has been partially modelled as a consolidation problem of a multi layered soils, usingthe method of finite differences. For this aim, a computer program in Visual Basic 6.0programming language has been prepared to handle the solution of consolidation problem inmulti-layered soils.In order to visualize the subsidence, settlement contour maps for the IAOIZ area have beenprepared based on the observed measurements.A study region in IAOIZ area, which also covers the maximum settlement bowl, has beenselected to model the subsidence. Three soil models have been prepared with the data fromthe nearby soil borings and the pumping well drillings. After assigning the soil parametersand forming a loading history, time dependent settlements of the each soil model has beenevaluated using the computer program. Time dependent settlements and the measuredsettlements have been compared to clarify the validity of each soil model.Keywords: land subsidence, ground water withdrawal, consolidation, finite differencemethod, computer analysis.