Settlement analysis of a cylindrical tank based on CPTU and SDMT results

Within the framework of an investment project a cylindrical tank to store liquid fuels was designed. It was founded under difficult soil and water conditions on alluvial subsoil composed of alternately deposited sands and organic soils. The result of an analysis of settlement of the building structure in the least advantageous situation, i.e. at the filling test, was considered an important criterion of correctness of the design. A MES 3D analysis of these settlements was conducted at the assumption of subsoil stratification identified geometrically using CPTU penetration and dilatometer testing (SDMT). Penetration in situ tests comprised also the basis for the evaluation of deformation parameters, quantifying the linear-elastic, isotropic models of layers. The leading parameter for each layer was the maximum (initial) G ₀ shear modulus. On the basis of this modulus and the stiffness model of the subsoil a quasi 3D Poisson's ratio was selected so that the condition of incompressibility was met. Correctness of calculation assumptions was verified by comparing theoretically predicted settlements with the results of their monitoring at the filling test stage. The presented paper may be seen as an example of the application of the concept of Experimental Soil Engineering (ESE), introduced extensively to present-day geotechnical design and based on simple, realistic mathematical models with parameters possibly best adapted to the reality, represented by the results of measurements.