Papers by Keyword: Liquefaction

Abstract: Seismic base isolation has emerged as one of the most effective strategies for mitigating vibrations induced by seismic excitations in structures. However, its efficiency can be compromised if the foundation system is incompatible with the isolator type or soil conditions, leading to undesirable structural responses during seismic events. While extensive research exists on isolator mechanisms and damping performance, comparatively fewer studies address the influence of foundation systems on the overall efficiency of base-isolated structures. This paper reviews the influence of foundation type and soil conditions on the performance of base isolation systems, emphasizing the importance of soil–structure interaction (SSI) and energy dissipation capacity. A comprehensive literature review of studies published over the last decade is presented, focusing on the comparative performance of shallow, deep, and hybrid foundations in supporting passive base-isolation systems. Findings indicate that shallow foundations, such as mat and spread footings, are effective for low to mid-rise structures on stiff soils, whereas deep and hybrid foundations offer superior stability and isolation efficiency in soft or liquefiable soil conditions. The study concludes that integrating foundation design with base-isolation mechanisms is essential for optimizing seismic performance.

Abstract: This research compares the increase in the liquefaction safety factor and the decrease in the settlements produced by liquefaction after applying soil improvement methods that mitigate the soil liquefaction phenomenon. The methods or improvement treatments analyzed are as follows: gravel columns; Rammed Aggregate Pier; and compaction injections. The scenario in which this evaluation was conducted is a sandy soil in the city of Chimbote, Peru, which has all of the necessary characteristics for this phenomenon to occur, namely sandy soil, low relative density, high water table and seismic zone. In addition, there was soil liquefaction in this city in 1970.

Abstract: Oil palm fruit waste (OPFW) was conducted using polyhydric alcohol (PA) as liquefaction solvent with H₂SO₄ in three different OPFW/PA ratio (1/2, 1/3 and 1/4). During the liquefaction, cellulose, semi-cellulose and lignin are decomposed, which results in changes of acid value and hydroxyl value. The liquefied OPFW were characterized by Fourier Transform infrared (FT-IR) spectroscopy. The hydroxyl and acid values of the liquefied oil palm fruit waste (OPFW) varied with the liquefied conditions. It was observed that with an increase in the liquefaction solvent (PA) amount in the mixture resulted in a high acid value and hydroxyl value for the OPFW. FT-IR spectroscopy analysis showed that the resulting biopolyol was suitable monomer for polyurethane (PU) synthesis for the production of PU foams.

Abstract: Liquefaction is known to be an effective method for converting biomass into a biopolyol. The biomass liquefaction of oil palm fruit waste (OPFW) in the presence of liquefaction solvent/polyhydric alcohol (PA): Ethylene glycol (EG), polyethylene glycol 400 (PEG400) and glycerol using sulfuric acid as catalyst was studied. For all experiments, the liquefaction was conducted at 150°C and atmospheric pressure. The mass ratio of OPFW to liquefaction solvents used in all the experiments was 1/2, 1/3 and 1/4. The results revealed that almost 50% of the oil palm fruit waste converted into liquid product within 2 hours at 150°C with OPFW/PA ratio of 1/4. Biopolyol produced under different condition showed viscosities from 210 to 650 Pa.s. The result in this study may provide fundamental information on integrated utilization of oil palm fruit waste via biomass liquefaction process.

Abstract: The present paper proposed a cyclic plasticity model with a non-associativity parameter, i.e., the model includes non-associative flow rule and associative one. In the present model, the non-associative parameter controls the non-associativity. The model is derived based on the non-linear kinematical hardening rule with two hardening parameters for both the volumetric and deviatoric strains. From the simulation by the present model, we have found the strong non-associativity leads to the large decrease in the mean effective stress, i.e. almost zero mean effective stress during the cyclic deformations under undrained conditions while the model with associated flow rule is not.

Abstract: After the introduction of the ANCOLD Guidelines on the dam design to withstand earthquakes in 1998, many dams in Australia have been reviewed on their capacity to withstand earthquakes. As results, many of them have been upgraded in the last two decades to increase their resistance against seismic loading. This paper presents the current methods used in Australia to undertake seismic upgrade for earth dams. The paper firstly presents brief discussion on the current methods of seismic stability assessment of earth dams. It then discusses the advantages and limitations of the available methods for seismic rehabilitation. Finally, it presents one of the case histories of seismic upgrade in Victoria, Australia.

Abstract: Geomaterials with typical low unit weight and high porosity are significantly prone to liquefaction as a result of dynamic – seismic load. Investigation of geomaterials that are prone to liquefaction due to seismic load can use certain SPT and CPT penetration tests. The method of investigating liquefaction caused by seismic activity was developed based on numerous penetration tests of sandy or silty–sandy soils and was elaborated in detail at the Workshop on Evaluation of Liquefaction Resistance of Soil, NCEER, Salk Lake City, USA, 1996. In the present paper, the results of penetration CPT test conducted at the ash impoundment in Zemianske Kostoľany are analyzed using methodology NCEER.

Abstract: Pile foundation is the practical method to enhance earthquake-resistant ability for structures located in liquefiable soil sites. Soil liquefaction impact has been occurred such as Kashiwazaki-Kariwa NPP in 2007 Chūetsu offshore earthquake because of the soft backfill soil. To understand the behavior of pile foundations in liquefied soil during earthquake attack and conform to nuclear standard, seismic analysis with soil-structure interaction considering liquefaction using the finite difference program FLAC3D is developed to renew the traditional method used in nuclear industry. The models are verified according to a series of centrifuge model test results conducted in National Central University, Taiwan, to show the accuracy of seismic response prediction, and it provides the more advanced tool to demonstrate the detail of seismic response so that the utility and authority can easily decide the disaster prevention strategy.

Abstract: The liquefaction failure forms are reviewed, including foundation strength failure, sand boil, seismic settlement, large ground displacement and flow slide. Taking pile foundations and buried pipeline as examples, there suggested some measures to reduce hazards of liquefaction.

Abstract: Through collecting real liquefaction in-situ data available worldwide, the correlations of influencing characteristics parameters such as PGA, water table depth, buried depth of sandy layer, SPT counts and shear wave velocity with respect to liquefaction were analyzed by means of Pearson correlation method. The correlative performance of the characteristic parameters with liquefaction was comparatively analyzed under conditions of varying buried depths, water tables and seismic intensities. The real correlations of the characteristic parameters with liquefaction were obtained corresponding to real dynamic loading, real buried condition and in-situ testing data. The analytical results show that water table, buried depth of sandy layer, SPT and shear wave velocity keep negative correlations with respect to liquefaction while correlation of PGA with liquefaction was positive. The correlations of buried depth of sandy layer, SPT were remarkable while the correlations of water table, shear wave velocity were weak. The correlation coefficient of SPT was the largest, followed by buried depth of sandy layer, PGA and water table; and the correlation coefficient of shear wave velocity was the smallest. The results presented herein can be used for updating the liquefaction evaluation methods in the codes.