Geotechnical data management and analysis system for organic soil

Organic soil deposits often cause construction difficulties due to their inadequate strength and high compressibility. Various practices routinely used to remedy this situation such as excavation and surcharging, have proven to be costly and sometimes even ineffective. Hence, the feasibility of dynamically replacing Florida organic soil with sand columns (DR) was investigated at the University of South Florida (USF) as a viable alternative to the above techniques. This extensive investigation included laboratory classification and consolidation tests, model DR tests and full-scale field DR and surcharge tests.; Although many researchers have studied the compressibility of organic soils, direct correlation of compressibility properties to basic classification properties are not available. Thus, one objective of this dissertation research was to develop analytical correlations between the field compressibility properties and the organic content of a soil deposit as well as the expected construction pressure. This was achieved by extending previous research conducted at USF in which the laboratory measured Gibson and Lo (1961) compressibility parameters were correlated to the organic content and the consolidation pressure. Comparison of analytical predictions with actual data from the surcharge test show reasonable agreement.; The second objective of this dissertation research was to formulate a quality control program that can continuously evaluate the stabilization of an organic soil deposit during DR and thus enable the identification of the optimum treatment level. This was accomplished by computing the dynamic settlement modulus (DSM) parameter based on acceleration records and other measurements. It is illustrated how the prediction of the optimum treatment level based on the evaluation of DSM agrees very well with other visual observations made during field DR implementation. An additional advantage of employing the DSM method is the availability of correlations between DSM and other useful soil properties such as the modulus of elasticity.; The final aim of this dissertation was to incorporate the above methodologies in a computer-based data management system, using state-of-the-art computational facilities. In this regard, a Data Management System for Organic Soils (DMSOS) was established to enable the acquisition, management and analysis of organic soil data to be performed in a manner compatible with that of other geotechnical databases. It is shown how DMSOS based data and correlations can be efficiently utilized to predict (1) the compressibility and other useful properties of an organic soil deposit from easily measurable basic index properties and (2) the degree of improvement of a DR treated organic soil site at any given stage of treatment, in a graphical environment. This innovation will indeed be an invaluable tool for the Florida Department of Transportation in highway construction practices in the state.