General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms 1 The prediction of the stress-strain response of granular soils under large numbers of repeated 19 loading cycles requires subtle changes to existing models, although the basic framework of 20 kinematic hardening/bounding surface elasto-plasticity can be retained. Extending an existing 21 model, an extra memory surface is introduced to track the stress history of the soil. The 22 memory surface can evolve in size and position according to three rules which can be linked 23 with physical principles of particle fabric and interaction. The memory surface changes in 24 size and position through the experienced plastic volumetric strains but it always encloses the 25 2 current stress state and the yield surface; these simple rules permit progressive stiffening of 26 the soil in cyclic loading, the accurate prediction of plastic strain rate accumulation during 27 cyclic loading, and the description of slightly stiffer stress-strain response upon subsequent 28 monotonic reloading. The implementation of the additional modelling features requires the 29 definition of only two new constitutive soil parameters. A parametric analysis is provided to 30 MEMORY SURFACE HARDENING MODEL FOR GRANULAR SOILS UNDER 1 REPEATED LOADING CONDITIONSshow model predictions for drained and undrained cyclic loading conditions. The model is 31 validated against available tests on Hostun Sand performed under drained triaxial cyclic 32 loading conditions with various confining pressures, densities, average stress ratios and cyclic 33 amplitudes. 34

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This article investigates the development of volumetric strain nonuniformities in sand specimens subjected to drained cyclic triaxial compression loading. The assessment is performed by comparing volumetric strain determinations using an external volume gauge and local axial and radial strain measurements mounted on the center of the specimen. The experimental investigation has been performed for both frictional and enlarged lubricated ends on sand specimens of different densities and fabricated using both moist tamping and dry deposition techniques. It will be shown that considerable discrepancies between the global and local volumetric determination arise even in specimens tested with enlarged lubricated ends, as a result of different volumetric tendencies (contraction or dilation) of the center and the boundaries of the specimens. These discrepancies are more pronounced for dense specimens cycled at high average stress ratios and amplitudes. The influence of three different assumptions employed to account for the specimen's deformed profile (namely the right cylinder, parabolic, and sinusoidal profile) on the local volumetric determinations will be also assessed. Some recommendations for the need for local volumetric measurements will be attempted.

This article describes a liquefaction database that contains a summary of 209 liquefaction, non-liquefaction, and marginal case histories compiled from the 2010 Mw 8.8 Maule, 2014 Mw 8.2 Iquique, 2015 Mw 8.3 Illapel, and 2016 Mw 7.6 Melinka earthquakes, where the liquefaction phenomenon caused damage to buildings, bridges, roads, and drainage systems, generating millions in losses at the infrastructure level. The database structure is organized into nine main tables that contain site information, geotechnical tests, and seismic parameters. The main tables include the locations of the sites, surface evidence of liquefaction or absence of them, geotechnical parameters from boreholes, and geophysical and laboratory tests. The database contains 7977 m of standard penetration test logs and 390 m of cone penetration test soundings from 209 sites explored. In addition, the seismic parameters of these earthquakes include ground-motion intensity measures estimated for each site. The information in this database allows a better characterization of the seismic demand and the geotechnical properties of the soil involved in predicting liquefaction triggering in this subduction zone. The data associated with this article are available in DesignSafe, where users can freely download and process data to train or evaluate predictive liquefaction models.

A key aspect of permanent offshore structures is protection against scour. This is typically in the form of a blanket of coarse gravel or cobbles surrounding the structure. These coarse particles are selected for their high resistance to being displaced by strong currents and thus protect the underlying finer sand particles from scour. However, in the event of an earthquake, the foundation sand may be susceptible to some degree of liquefaction. This research investigates the effects of seismic-induced liquefaction over a scour blanket, and if sinking is inhibited by some combination of the additional effective stress imposed by the gravel together with the interlocking resistance that develops when coarse particles are subjected to relative displacements. In order to evaluate the stability of scour protection blankets, a programme of physical modelling was carried out, involving the assessment of different configuration of stone layers over a liquefiable material, and a monopile-type foundation. Models were subjected to scaled base shaking equivalent to earthquake loading. A mass-balance of particle sinkage showed that a filter layer was critical for maintaining the integrity of the armour stones. Based on displacement and pore water pressure measurements, it was found that the presence of the scour protection blankets improved the response of the liquefiable sand under seismic loading, and even inhibited the occurrence of liquefaction. This implied that a well-designed scour protection blanket can assist in protecting against earthquake effects also.