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Centrifuge modelling of earthquake-induced liquefaction on footings built on improved ground
Published in Andrew McNamara, Sam Divall, Richard Goodey, Neil Taylor, Sarah Stallebrass, Jignasha Panchal, Physical Modelling in Geotechnics, 2018
A.S.P.S. Marques, P.A.L.F. Coelho, S.K. Haigh, G.S.P. Madabhushi
Earthquake-induced soil liquefaction is a major cause of damage that occurs as a result of earthquake shaking of saturated deposits of cohesionless soils in seismically active regions. This phenomenon has proved to be a serious threat to modern societies, which are increasingly vulnerable to its serious effects, namely as a result of their strong dependence on sophisticated and widespread infrastructure that is built in liquefaction-prone areas. This is exacerbated by the fact that the problem is more and more likely to cause indirect repercussion in non-seismically active countries too, due to fast growing globalisation of the world economy. For instance, earthquake-induced damage in Taiwan can severely affect Western companies while the world economy would be threatened if earthquake-induced damage affected oil production capacity in Saudi Arabia, Venezuela or Iran. Moreover, as shown by the 2004 Sumatra earthquake, losses and human misery due to earthquakes can have worldwide repercussions due to the mobility of modern civilization and the power of contemporary media. Last but not the least, many multinational companies have working places in several locations all over the world that may be prone to seismic liquefaction effects. This may result in a significant amplification of the consequences around the globe.
Verification and validation of two-phase material point method simulation of pore water pressure rise and dissipation in earthquakes
Published in Andrew McNamara, Sam Divall, Richard Goodey, Neil Taylor, Sarah Stallebrass, Jignasha Panchal, Physical Modelling in Geotechnics, 2018
T. Kiriyama, K. Fukutake, Y. Higo
There have been repeated reports of soil liquefaction leading to disastrous effects such as soil outflows from developed residential lots, collapse of embankments, lateral spreading and uplift/settlement of structures. These ground-related disasters involve large deformations of the ground. To predict such large deformations and quantify ground safety, recently developed particle-based numerical methods that can handle large deformations are used. The authors focus in particular on the material point method (MPM) (Sulsky et al. 1994) and extend it as a simulation method based on a two-phase formulation. The simulation is compared with the results obtained in experiments using a centrifuge, demonstrating that it is able to predict the behavior of liquefied ground, including the rise in pore water pressure during an earthquake and its later dissipation.
Introduction
Published in Hector Estrada, Luke S. Lee, Introduction to Earthquake Engineering, 2017
Soil liquefaction occurs when loose, saturated granular soils temporarily change from a solid to a liquid state, losing their shear strength, which corresponds to a loss in effective stress between soil particles. Loose saturated (or moderately saturated) sands and nonplastic silts are most susceptible to this ground failure; however, in rare cases, gravel and clay can also experience liquefaction. In all cases, poor drainage within the loose soil causes an increase in the pore water pressure as the soil is compressed by the vibratory effect of seismic waves. As the load is transferred from soil to pore water pressure, the effective stress between particles is temporarily reduced, or eliminated, causing a corresponding decrease in shear strength. In some cases, the pore water pressure increases rapidly and a slurry (soil water mixture) forms that flows vertically to the surface, which can result in craters and sand boils as shown in Figure 1.3a. Liquefaction is responsible for some of the most spectacular failures caused by earthquakes as shown in Figure 1.3b. Following the 1964 Niigata, Japan earthquake, several apartment buildings experienced severe tilting and settlement. Fortuitously, the tilted buildings did not suffer major structural damage, and thus minimal human injury.
Influence of Substructure Levels on the Computed Seismic Performance of Low-Rise Structures
Published in Journal of Earthquake Engineering, 2021
Jaime A. Mercado, Luis G. Arboleda-Monsalve
One of the most important consequences of soil liquefaction is the damage induced to the existing infrastructure, quantified and documented in numerous case histories including settlement of buildings and bridges, foundation failures, lateral spreading of foundations, damage and flotation of buried utilities, and failure of retaining walls. Numerous research have been developed in the topic of soil liquefaction and significant improvement has been made, with the advent of numerical tools and methods, in the predicting capabilities of soil and structural behavior when an earthquake strikes.
Reliquefaction Assessment Studies on Saturated Sand Deposits under Repeated Acceleration Loading Using 1-g Shaking Table Experiments
Published in Journal of Earthquake Engineering, 2022
Gowtham Padmanabhan, Ganesh Kumar Shanmugam
Every year many earthquakes strike worldwide, causing risk to life and infrastructures. The amount of energy released during its incidence is considerable, and the area under the influence is pervasive causing severe damages to the infra-structures. One of the primary reasons for the damage is due to earthquake-induced soil liquefaction. Earthquake-induced soil liquefaction is a phenomenon where high excess pore water pressure generated in partially or fully saturated soil as a result of dynamic loading. When the ratio of excess pore water pressure to the initial effective vertical stress reaches unity, the soil is considered as “liquefied” and loses its shear resistance (Seed and Lee 1966). The effect of liquefaction and undrained behaviour of saturated sands under cyclic loading has been reported by various researchers and concluded that soil matrix plays a significant role in initiating liquefaction (e.g., Castro 1975; Ishihara, Tatsuoka, and Yasuda 1975; Martin 1975; Muley, Maheshwari, and Paul 2015; Papadopoulou et al. 2010; Poulos, Castro, and France 1985; Seed 1979; Seed et al. 1985; Sitharam and Vipin 2009; Vaid and Chern 1983). Further, the researchers suggested that relative density, initial stress conditions and acceleration amplitude also has its own influence in liquefaction behaviour of saturated sand deposits (Lee and Seed 1967; Castro and Poulos 1977; Vaid and Finn 1978; Vaid, Chern, and Tumi 1985; Sitharam, Govindaraju, and Sridharan 2004; Cubrinovski, Ishihara, and Poulos 2009; Maheshwari and Patel 2010; Kumar, Krishna, and Dey 2018a, b; Vijayasri, Raychowdhury, and Patra 2018). With the help of cyclic triaxial tests (Kumar, Dey, and Krishna 2020) studied the response of saturated soil during earthquakes and reported decrease in liquefaction potential and increase in Cyclic Stress Ratio (CSR) with increase in relative density.
Research on the feasibility of strengthening the soil structure by biomineralization
Published in Journal of the Chinese Institute of Engineers, 2021
How-Ji Chen, Ting-Meng Tsai, Chung-Hao Wu
Earthquakes are frequently accompanied by largely disasters. One important factor that causes ground-structure damage is soil liquefaction. In the case of a sandy-soil area where the groundwater level is high, soil liquefaction is likely to be triggered by various external causes such as seismic forces or other disturbances. Soil liquefaction can be majorly prevented by increasing the soil stiffness or ground-bearing capacity as well as by increasing the shear strength of the soil using stratum-improvement technologies.