170,015 research outputs found
Directional response of a reconstituted fine-grained soil. Part I: experimental investigation
No full textThis paper discusses the results of a large experimental program designed to investigate in a systematic manner the main features of the incremental response of fine-grained soils. The results are obtained from triaxial stress probing experiments carried out on a French silty clay (Beaucaire Marl). All the tests have been performed on reconstituted specimens, normally consolidated to an initial state which is either isotropic or anisotropic. In the interpretation of the experimental results, extensive use is made of the concept of strain response envelope. The response envelopes obtained for different stress increment magnitudes are remarkably consistent with each other and indicate an inelastic and irreversible material response, i.e. a strong dependence on the stress increment direction, also at relatively small strain levels. A companion paper (Int. J. Numer. Anal. Meth. Geomech., this issue, 2006) assesses the performance of some advanced constitutive models in reproducing the behaviour of reconstituted Beaucaire Marl as observed in this experimental progra
Advanced numerical modelling of seismic response of a propped r.c. diaphragm wall
No full textThe paper presents some results from a number of dynamic FE simulations carried out to investigate the seismic response of a propped flexible retaining wall in a dry coarse-grained soil, considering two bedrock acceleration time histories as seismic input. Two dierent soil plasticity models have been considered in this study: an anisotropic hardening, critical state model for cyclic/dynamic loading of sands and the classical Mohr-Coulomb elastic-perfectly plastic model with non-associative flow rule. The results obtained allow to highlight the main features of the seismic performance of such type of flexible retaining structures and to evaluate the effects of the constitutive assumptions made on soil behavior on the predicted wall displacements and structural loads
Numerical integration of elastoplastic constitutive equations for geomaterials with extended hardening rules
No full textA Generalized Backward Euler algorithm for the numerical integration of an isotropic hardening elastoplastic model for mechanical and chemical degradation of bonded geomaterials
No full textA new tool for wide-area analysis of transient pore water pressures in layered shallow covers prone to failure
No full textIn this paper we present a modified version of an existing, physically-based model for shallow landslide susceptibility analysis over large area. In general, the potentially unstable soil cover is considered uniform and homogeneous, over impervious underlying bedrock. In several case studies, this was proven to be unrealistic. The possibility of taking into account the detailed configuration of the soil cover allows having a more accurate estimate of the potentially unstable volumes, which determine the intensity of the considered phenomena. The newly–implemented tool was tested by comparing its results with those obtained from a Finite Element (FE) commercial code, solving the same 1D problem. Then, a parametric analysis was carried out by varying the permeability ratio between the two layers, with the aim of examining the influence of such parameter on the pore-pressure distribution along the vertical profile. As expected, as the permeability ratio increases, the underlying layer tends to behave as an impervious boundary. This increases the chance that only the most superficial soil layer fails. An analysis of the routine performance and efficiency was also done to investigate the response of the model with various tolerances and different spatial discretizations along the vertical profile. As main result, it is shown that the variability in ground conditions may highly affect the pore water pressures and the proposed seepage model can be successfully whether detailed stratigraphy site investigations are available
Influence of a soil nailing application on tunnel excavation in slightly overconsolidated clays
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