An alternative process-based approach to predicting the response of water-saturated porous media to harmonic hydrodynamic loads

Methods have been developed to predict how hydrodynamic loads acting on nearly saturated porous media are transmitted to the subsoil. In line with the effective stress principle of Terzaghi, these methods apply the boundary conditions that the effective stresses at the surface of a porous medium are zero, and that the pore water pressures...

Hydrothermal liquefaction of Elaeis guineensis trunks: Lessons learned from a case study in Guatemala

The oil palm industry has been under public scrutiny during the last decades due to environmental and social issues related to its practices. Oil palm (Elaeis guineensis Jacq.) trunks (OPTs) are of special interest as they are left idle in the field after the replanting process which is performed every 25 years. This common practice results...

A New Strategy for Mitigating Pipeline Uplift in Liquefied Soils

Seismic-induced liquefaction is one of the main hazards for pipelines buried in saturated granular materials. When soil is partially or completely fluidized, a lifeline, although installed in superficial trenches in which the coarse backfill soil usually is compacted, may experience a sudden uplift and damages. To reduce pipeline uplift and...

Shaking Table Test on Mitigation of Liquefaction-Induced Tunnel Uplift by Helical Pile

The tunnels located in the shallow depths of loose saturated sand are significantly prone to liquefaction-induced uplift. Research works are, therefore, in progress to propose efficient techniques for mitigating uplift. In this study, 1 g physical modeling was used to assess the performance of helical piles for decreasing liquefaction-induced...

Pipeline flotation in liquefied sand: A simplified transient model

Submarine buried pipelines are often laid in trenches backfilled with loose sandy soil, which is intrinsically prone to liquefaction. When liquefaction is triggered, the soil tends to behave as a viscous fluid with vanishing shear strength and very limited ability to restrain structural displacement, for instance during the occurrence of...

Effect of Pavement Thickness and Width on Liquefaction-Induced Settlements and the Contribution of Sand Ejecta in Total Settlement

This paper investigates the settlement in a pavement due to soil liquefaction. Four 1-g shaking table tests were performed on saturated sand bed-pavement model to understand the factors affecting the liquefaction-induced settlements and their relation to the pavement thickness and width. All the tests were performed with a base acceleration...

Large-scale physical modelling of static liquefaction in gentle submarine slopes

Planning a monitoring campaign for a natural submarine slope prone to static liquefaction is a challenging task due to the sudden nature of flow slides. Therefore, gaining a better insight by monitoring the changes in pore pressure and acceleration of the soil mass, prior to and at the onset of static liquefaction, of submerged model slopes...

Ultimate lateral pressures exerted on buried pipelines by the initiation of submarine landslides

Submarine slope instabilities are considered one of the major threats for offshore buried pipelines. This paper presents a novel method to evaluate the ultimate pressure acting on a buried pipeline during the liquefaction of an inclined seabed. Small-scale model tests with pipes buried at three different embedment ratios have been conducted...

Ground response during offshore pile driving in a sandy slope

This paper presents an analysis of field measurements obtained during pile installation tests in a submerged sandy slope. The field test was performed in 2016 as part of the construction of a new sea lock in the Netherlands. Ground vibrations and excess pore pressures were to be limited in order to prevent damage to neighbouring locks and...

Pile driving and submarine slope stability: a hybrid engineering approach

During pile installation into a submerged, sandy slope, liquefaction mechanisms including flow and cyclic liquefaction warrant attention. Because of the interconnection of these mechanisms, evaluating slope stability during and as a result of vibration-inducing construction activity is not trivial. This paper presents a practical approach to...

Centrifuge modelling of submarine landslides due to static liquefaction

Sand erosion and scouring caused by waves and marine currents result in gradual increase of local seabed inclination and formation of slopes around hydraulic structures and offshore foundations. During this process, shear stresses in the soil body increase monotonically which may lead to static liquefaction and damage of the adjacent offshore...

Analysis of biomass hydrothermal liquefaction and biocrude-oil upgrading for renewable jet fuel production: The impact of reaction conditions on production costs and GHG emissions performance

This paper shows a detailed analysis of a biomass HTL process by considering changes in three main reaction variables (i.e. catalysts (water, Na₂CO₃(aq.), and Fe(aq.)), temperature (280–340 °C), and catalysts/biomass mass ratio (0–0.33 kg catalysts/kg biomass)), and by assessing their influence on the techno-economic and...

Modeling of liquefaction using two-phase FEM with UBC3D-PLM model

Soil liquefaction describes a loss of strength of saturated sand upon sudden or cyclic loading. A slight disturbance of such a soil’s fabric might lead to severe damage, e.g. the collapse of sea dikes. Accurate modeling of the state transition between saturated soil and a liquefied soil-water mixture, as well as post-liquefaction phenomena, is...