Simplified procedures for assessing soil liquefaction during earthquakes

Iwasaki, Toshio; Arakawa, Tadashi; Tokida, Ken-ichi

doi:10.1016/0261-7277(84)90027-5

Cited by 161 publications

(169 citation statements)

References 2 publications

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“…Nine liquefaction forecasting models are compared in this paper, including three alternative implementations of the liquefaction potential index (LPI) method proposed by Iwasaki et al (1984), three versions of the liquefaction models included in the HAZUS ®MH MR4 software (NIBS, 2003) and three distinct models proposed by Zhu et al (2015). This section summarizes how each of the models are applied to make site-specific liquefaction forecasts.…”

Section: Liquefaction Assessment Modelsmentioning

confidence: 99%

Evaluating simplified methods for liquefaction assessment for loss estimation

Kongar

Rossetto

Giovinazzi

2017

Nat. Hazards Earth Syst. Sci.

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Abstract. Currently, some catastrophe models used by the insurance industry account for liquefaction by applying a simple factor to shaking-induced losses. The factor is based only on local liquefaction susceptibility and this highlights the need for a more sophisticated approach to incorporating the effects of liquefaction in loss models. This study compares 11 unique models, each based on one of three principal simplified liquefaction assessment methods: liquefaction potential index (LPI) calculated from shear-wave velocity, the HAZUS software method and a method created specifically to make use of USGS remote sensing data. Data from the September 2010 Darfield and February 2011 Christchurch earthquakes in New Zealand are used to compare observed liquefaction occurrences to forecasts from these models using binary classification performance measures. The analysis shows that the best-performing model is the LPI calculated using known shear-wave velocity profiles, which correctly forecasts 78 % of sites where liquefaction occurred and 80 % of sites where liquefaction did not occur, when the threshold is set at 7. However, these data may not always be available to insurers. The next best model is also based on LPI but uses shear-wave velocity profiles simulated from the combination of USGS V S30 data and empirical functions that relate V S30 to average shear-wave velocities at shallower depths. This model correctly forecasts 58 % of sites where liquefaction occurred and 84 % of sites where liquefaction did not occur, when the threshold is set at 4. These scores increase to 78 and 86 %, respectively, when forecasts are based on liquefaction probabilities that are empirically related to the same values of LPI. This model is potentially more useful for insurance since the input data are publicly available. HAZUS models, which are commonly used in studies where no local model is available, perform poorly and incorrectly forecast 87 % of sites where liquefaction occurred, even at optimal thresholds. This paper also considers two models (HAZUS and EPOLLS) for estimation of the scale of liquefaction in terms of permanent ground deformation but finds that both models perform poorly, with correlations between observations and forecasts lower than 0.4 in all cases. Therefore these models potentially provide negligible additional value to loss estimation analysis outside of the regions for which they have been developed.

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Section: Liquefaction Assessment Modelsmentioning

confidence: 99%

Evaluating simplified methods for liquefaction assessment for loss estimation

Kongar

Rossetto

Giovinazzi

2017

Nat. Hazards Earth Syst. Sci.

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“…Table 1 shows results of physical tests of the fill material containing coal ash. The soil particle density ρ s of the coal ash is in the range of 2.326-2.484 g/cm 3 , and degree of compaction D c of 80%-85%. Additionally, the fill material has fine sand, fine grain content rate F c of 9.0%-19.0%.…”

Section: Investigation Sitementioning

confidence: 99%

“…This examination were based on assumption, liquefaction resistance ratio in liquefiable layer is close to the same despite the difference in depth. The factors of safety for liquefaction F L (Iwasaki, 1984) were evaluated to be less than 1.0. The results mean the fill material had the potential of the liquefaction in the 2011 Great East Japan Earthquake.…”

Section: Liquefaction Evaluation Using Cumulative Damege Theorymentioning

confidence: 99%

Investigation of liquefiable property and S-wave velocity distribution focused on coal ash used for rail yard embankments

Sato

Matsumaru

Kudo

2017

JGS Special Publication

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In the 2011 Great East Japan Earthquake the rail yard embankment constructed by use of coal ash was damaged by severe liquefaction, resulting in the differential settlement of railway track. In the railway the settlement is limited to ensure safety, however the evaluation method for differential settlement is not established. It is thus necessary to establish the evaluation method for the differential settlement of railway track induced by liquefaction. In this study, cyclic undrained triaxial tests for the fill material contained coal ash were performed to validate whether it was liquefied. It was found that the fill material was possibility to be liquefied sufficiently. In addition, field level survey and surface wave exploration method were conducted to examine the effect of the thickness of liquefiable layer and S-wave velocity distribution on differential settlement caused by liquefaction. The results revealed that the differential settlement is concerned with distribution of the S-wave velocity and the thickness of the liquefiable layer.

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“…To interpret the obtained values of IP L (Equation 8), a classification proposed by Iwasaki (1982) and modified by Sonmez (2003) is used. In Table 3 liquefaction potential categories are presented.…”

Section: Liquefaction Potential Index (Ip L )mentioning

confidence: 99%

Real Probability of Liquefaction, Liquefaction Potential Index Based In CPTU Data for Golem Area, In Albania

2015

International Conference on Architecture, Structure and Civil Engineering (ICASCE-15) Sept. 7-8, 2015 Antalya (Turkey)

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Simplified procedures for assessing soil liquefaction during earthquakes

Cited by 161 publications

References 2 publications

Evaluating simplified methods for liquefaction assessment for loss estimation

Evaluating simplified methods for liquefaction assessment for loss estimation

Investigation of liquefiable property and S-wave velocity distribution focused on coal ash used for rail yard embankments

Real Probability of Liquefaction, Liquefaction Potential Index Based In CPTU Data for Golem Area, In Albania

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