Cyclic undrained triaxial tests were carried out on saturated and unsaturated loose specimens of three fine-grained materials. The results confirm that, as the saturation degree decreases, liquefaction resistance sharply increases. In interpretation results, first step was assessment reliability use 5% strain amplitude criterion to define attainment liquefaction. With this aim, analysed assuming that soil behaves an equivalent viscous material. It is shown characteristic values viscosity...

Induced partial saturation (IPS) is considered to be one of the most promising technologies tackle soil liquefaction risk. The mitigation susceptibility loose partially saturated sandy soils linked high volumetric compressibility gas or air bubbles entrapped in continuous water phase. Based on a large amount experimental data, new formulation potential strain (εv*) nonsaturated introduced overcome some inconsistencies possible dissolution bubbles, that may not neglected at laboratory scale...

Fully liquefied soils behave like viscous fluids, and models developed within the framework of soil mechanics fail to catch their behaviour on verge liquefaction or after it. Several research works have shown that modelling as a fluid is physically more convincing. Such an equivalent can be characterised via apparent viscosity (η) (sharply dropping when triggered) which modelled power law function shear strain rate (pseudo-plastic fluid), depending two parameters: consistency coefficient (k)...

The increasing interest in the undrained cyclic behaviour of unsaturated soils is justified by evidence beneficial effect desaturation on liquefaction resistance and thus strictly connected with need to put forth sound tools be used design Induced Partial Saturation (IPS) interventions. IPS still far from being a routine technology because lack such tools, as well simple technologies obtain preserve it site. This paper offers contribution first issue, based energetic interpretation...

Earthquake-induced soil liquefaction is a catastrophic phenomenon that can damage existing building foundations and other structures, resulting in significant economic losses. Traditional mitigation techniques against present critical aspects, such as high construction costs, impact on surrounding infrastructure effects the environment. Therefore, research ongoing order to develop new approaches technologies suitable mitigate risk. Among innovative countermeasures liquefaction, Induced...

In saturated sandy soils liquefaction triggering is generally well-identified according to stress or strain criteria. On the contrary, attainment of in non-saturated still a cause discussion scientific community. Even if resistance higher than that ones, these may liquefy, as well. The increasing interest for cyclically mechanical behaviour due fact desaturation induced partial saturation can be used useful mitigation techniques against soil liquefaction. Therefore, it important define,...

Abstract Experimental evidence shows that earthquake induced liquefaction can occur more than once in sandy soils. Moreover, despite an increase soil density caused by the dissipation of excess pore pressure earthquakes, resistance soils have experienced may be lower virgin This paper offers insight into this topic starting from analysis undrained monotonic behavior post-liquefied sands means tests performed with a simple shear cell equipped flexible boundaries, which maintains constant...

The management of the huge amount dredged sediments is an important issue to be solved worldwide, and dewatering by far most critical step when fine grained are involved. Different technologies have been proposed in time speed up process. Even though electro-kinetic treatment principle one them, it has not implemented yet at industrial scale, only few trial applications known. For such a reason, multidisciplinary research activity ongoing University Napoli Federico II framework EU commitment...

The cyclic simple shear tests can be used to reproduce in laboratory the complex behaviour of soil during an earthquake, simulating continuous rotation principal stress axes. In this research a comparison results between carried out with confining pressure or rings is reported. A apparatus carry (the conventional way tests) and applied specimen through pressurized water, where K0 condition consolidation guaranteed by sophisticated control system. apparatus, both configurations, described...

The recent earthquakes that hit Italy have shown the built heritage is at risk not only because of inertial and kinematic stresses directly induced on structure by shaking, but also possible soil liquefaction phenomena. techniques generally used to mitigate susceptibility in case new constructions (vibro-compaction, dynamic compaction, etc.), are suitable for existing buildings. Within a large European project (LIQUEFACT), University Napoli studying innovative improvement mitigation densely...

Postshaking soil volumetric strains of liquefiable soils are technical interest because they cause a relevant part the total settlements experienced by site interest. In case intermediate soils, such as sandy silts or silty sands, reconsolidation affected amount fines. The note reports results laboratory cyclic undrained tests carried out to study liquefaction resistance and postliquefaction behavior sand-silt mixtures reconstituted with increasing nonplastic fines [0<fines content...

One of the main goals LIQUEFACT project is analysis effectiveness some ground improvement techniques in mitigation seismically induced soil liquefaction risk. This aspect was addressed via a comprehensive experimental program by means laboratory and centrifuge tests, as well carrying out number tests field trial located Pieve di Cento (Italy), where shaker placed at level to generate cyclic shear stresses induce significant build-up pore pressure shallow liquefiable sandy layer. Three series...