The paper presents in a comprehensive way issues related to propagation in a soil environment of vibrations originating during sheet piling vibratory driving. Considerations carried out comprised the FEM analysis of initial-boundary behaviour of the subsoil during impacts accompanying the works performed. The analysis has used the author’s RU+MCC constitutive model, which can realistically describe complex deformation characteristics in soils in the field of small strains, which accompany the phenomenon of shock propagation. The basis for model creation and for specification of material parameters of the presented model consisted of first-class tests performed in a triaxial apparatus using proximity detectors guaranteeing a proper measurement of strains ranging from 10(–1) to 10(–3) % and bender elements. Results obtained from numerical analyses were confronted with results of field tests consisting in measurements of acceleration amplitudes generated on the ground surface due to technological impacts versus the distance from vibration source.
FC+MCC to prosty model stanu krytycznego, mający w założeniu trafnie przewidywać odpowiedź ośrodka gruntowego na monotoniczne ścieżki obciążenia zarówno przy małych, jak i dużych deformacjach. W artykule uwagę skupiono na metodach kalibrowania modelu, przedstawiając optymalny sposób doboru parametrów. Przeprowadzono także obliczenia prostego fundamentu z zastosowaniem zaawansowanego programu MES, przy użyciu modelu FC+MCC.
The paper presents a reasonably advanced constitutive law for soil - a hybrid of the Modified Cam Clay and the Fahey - Carter models. The Modified Cam Clay model is an isotropic hardening elasto-plastic one originated by Burland (1967) within the critical state soil mechanics. This model is widely applied in today's geotechnical analysis. It realistically describes mechanical soil behaviour in the normal consolidation states. The other one is designed to ensure more adequate soil responses to reloading paths (within the overconsolidation stress subspace), particularly in the range of small strains. The model has been implemented in the FEM computer code Z_SOIL.pc 7.32. To test the influence of the small strain nonlinearity on soil - structure interaction as well as to exhibit the ability of the proposed model to simulate this effect realistically, a comparative study based on the FEM solution has been carried out. As a benchmark, a strip footing founded on a thick homogeneous cohesive soil layer in two different overconsolidation states has been used. The soil response to a load has been simulated assuming two models: original MCC and FC+MCC.
W artykule przedstawiono koncepcję oraz porównanie z danymi doświadczalnymi modelu stanu krytycznego opartego na modelu Modified Cam-Clay w obszarze normalnej konsolidacji i modelu Faheya-Cartera w obszarze prekonsolidacji. Analiza tak powstałego modelu została dokonana i przedstawiona w konfrontacji z trójosiowymi badaniami z drenażem kaolinu.
EN
An idea and comparision with experimental data of critical state model which is Modified Cam-Clay model in normal consolidation and Fahey-Carter's one in preconsolidation zone is presented. Analysis of this model and confrontation with drained triaxial tests of kaolin were carried out and presented.
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