This paper presents experimental investigations on the feasibility of using a sand-rubber deformable granular layer as low-cost seismic isolation strategy for developing countries. The mechanical characteristics potential failure mechanism inside are investigated. Direct shear testing is performed to quantify angle friction three different mixtures subjected vertical stress levels. experimentally derived compared corresponding values pure rubber and sand samples. frictional sliding between...

This paper provides a theoretical derivation for the unconfined compression strength of artificially cemented granular soils. The proposed developments are based on concept superposition failure contributions soil and cement phases. matrix obeys critical state mechanics concept, whereas phase can be described using Drucker-Prager criterion. In process, analytical relation is suitably adjusted to parallel recently empirical relationship that links soils an porosity/cement ratio parameter....

Keywords: anisotropy ; laboratory tests reinforced soils sands theoretical analysis ... Show All

For fibre-reinforced granular soils, the efficiency of fibres is governed by local fibre–grain interaction mechanism. This mechanism evaluated, in this paper, using a modified version shear-lag stress theory. While theory provides description stress-transfer at fibre–matrix interface level, it also generates distribution along fibre. The proposed model explicitly accounts for effects geometrical fibre and size characteristics, stiffness, global soil density non-linearity behaviour. An...

SUMMARY Based on hypotheses derived directly from experimental observations of the triaxial behaviour, a constitutive model for fibre reinforced sands is built in this paper. Both sand matrix and fibres obey their own law, whereas contributions are superimposed using volumetric homogenization procedure. The Severn‐Trent model, which combines well‐known concepts such as critical state theory, Mohr‐Coulomb like strength criterion, bounding surface plasticity kinematic hardening, adopted...

The nature of soil stiffness at small strains remains poorly understood. relationship between (e.g. shear stiffness, G 0 ) and isotropic confining pressure (p′) can be described using a power function with exponent (b), that is, = A (p′/p r b , where is constant p an arbitrary reference pressure. Experimentally determined values are usually around 0·5 these higher than the value 0·33 analytically Hertzian theory. theory considers contact two smooth, elastic spheres; however, in reality,...

The present work proposes a new theoretical model for predicting both the splitting tensile strength (qt) and compressive (qu) of artificially cemented sand assesses their ratio given material. proposed is based on concept superposition failure contributions cement phases. matrix obeys critical state soil mechanics, while phase can be described using Drucker-Prager criterion. analytical solutions are compared against results tests three different types clean cured time periods. While...

In this study experimental data on a model soil in cubical cell are compared with both discrete element (DEM) simulations and continuum analyses. The experiments used point source transmitters receivers to evaluate the shear compression wave velocities of samples, from which some elastic moduli can be deduced. Complex responses perturbations generated by bender/extender piezoceramic elements were those found controlled movement particles DEM simulations. generally satisfactory agreement...

Recent results of in situ measurements and their interest for a seismic assessment existing buildings are presented analysed. The present paper (Part I) is devoted to the experimental programme. response ambient vibrations, harmonic excitation shock loading recorded on intact but also after structure or vicinity was modified. These tests aim identify dynamic behaviour ordinary built conventional practise. Moreover, taking advantage demolition, it possible (through these tests) determine...

In practice, laterally loaded piles are most often analysed using a ‘beam-on-non-linear-Winkler-foundation’ approach, whereby the soil–structure interaction is modelled by means of p–y curves. Although well-calibrated curves exist for non-liquefied soils (e.g. soft clay and sand), profession still lacks reliable liquefied soils. fact, latter should be consistent with observed strain-stiffening behaviour exhibited samples in both element physical model tests. It recognised that this induced...

The addition of flexible fibres to granular, cohesionless soils, has a marked influence on the stress:strain and volumetric response. Experimental observations provide inspiration for development continuum models mechanical, pre-failure behaviour these fibre/soil mixtures. Such generic deduced mechanisms response should be applicable other combinations soils such as plant roots. Two features are particularly important: distribution orientations (no method preparation produces an isotropic...

The undrained behavior of very loose Hostun RF sand in triaxial compression and extension tests is described. samples are consolidated isotropically or anisotropically along constant effective stress ratio paths. Very exhibits partial liquefaction, deviator peak at relatively low to axial strain, gradual post-peak reduction a small residual value large strains, sharp loss mean pressure due generation pore overall volume reduction. instability line Lade examined the case extended for...

The interest of in situ measurements (presented Part I paper) for a seismic assessment existing buildings is analysed this paper. It shown that the experimental modal characteristics obtained on regular concrete structures are described successfully by suited Timoshenko beam modelling. For given structure, taking into account data, corresponding model, and choosing maximum tensile strain as damage criterion key structural elements, level ground acceleration can be determined. This so-called...