scholarly journals Liquefaction potential assessment of saturated loess

2021 ◽  
Vol 50 (1) ◽  
pp. 37-44
Author(s):  
Doncho Karastanev ◽  
Boriana Tchakalova
Keyword(s):  
Free Field ◽  
Danube River ◽  
Substantial Part ◽  
Eurocode 8 ◽  
Seismic Zone ◽  
Liquefaction Potential ◽  
Fine Grain ◽  
Field Evidence ◽  
Simplified Procedure ◽  
Ground Profile

Usually, soils with mainly fine grain-sized content, as loess, are considered to have low liquefaction potential. Regardless of this, many researchers have analyzed and presented much field evidence that silty soil (in particular loess) liquefaction occurred under certain conditions. In Bulgaria, the first loess river terrace (T1) within the Danube River lowland areas is covered by low plasticity silty loess with a thickness of 10–12 m. Тhe groundwater level is often located between 5 m and 8 m in depth so that substantial part of loess deposits are saturated and immersed. Meanwhile, that region of North Bulgaria is under the influence of the Vrancea seismic zone in Romania, which is able to generate strong earthquakes with magnitudes M≥7.0. The present paper aims to assess the liquefaction potential of loess in a ground profile representative of the T1 loess river terraces by the so-called simplified procedure based on SPT, which is incorporated in the software code NovoLiq. The safety factor against liquefaction FSL is estimated at the respective depths in one-dimensional model of the ground profile for free-field conditions at varying peak ground accelerations amax. The critical amax, at which liquefaction of loess is possible according to the assumptions of the applied simplified procedure and the requirements of the National Annex of Bulgaria to Eurocode 8, has been established.

CHARACTERIZATION OF LIQUEFACTION RESISTANCE OF SAND: EFFECT OF INITIAL FABRIC

2014 ◽  
Vol 08 (01) ◽  
pp. 1450001 ◽  
Author(s):  
BO LI ◽  
XIANGWU ZENG ◽  
HAO YU
Keyword(s):  
Depositional Environment ◽  
Design Method ◽  
Free Field ◽  
Recent Experience ◽  
Permeability Test ◽  
Fabric Anisotropy ◽  
Liquefaction Resistance ◽  
Liquefaction Potential ◽  
Centrifuge Tests

The micro-fabric of deposition reflects the imprints of its geologic and stress history, its depositional environment, and its weathering history. Recent experience shows that the fabric anisotropy does influence the static and dynamic behavior of granular materials. In this study, a series of centrifuge tests are conducted to investigate the effects of fabric anisotropy on the dynamic response in the free field. The results show the acceleration, pore pressure, and residual settlement is significantly affected by the fabric anisotropy of the ground, which shows the liquefaction resistance of the ground. Meanwhile, the response of acceleration is analyzed in frequency domain, which shows that the model prepared by 90° absorbs more energy than that of 0°. To verify the effects induced by the initial fabric, permeability test are conducted and related to the liquefaction potential. The results indicate the fabric anisotropy should be incorporated into the design method.

scholarly journals LPI Based Earthquake Induced Soil Liquefaction Susceptibility Assessment at Probashi Palli Abasan Project Area, Tongi, Gazipur, Bangladesh

2018 ◽  
Vol 10 (2) ◽  
pp. 105-116
Author(s):  
A. H. Farazi ◽  
N. Ferdous ◽  
A. S. M. M. Kamal
Keyword(s):  
Threshold Value ◽  
Flood Plain ◽  
Standard Penetration Test ◽  
Soil Liquefaction ◽  
Cumulative Frequency ◽  
Liquefaction Potential ◽  
Project Area ◽  
Potential Index ◽  
Liquefaction Hazard ◽  
Simplified Procedure

This study aims at evaluation of seismic soil liquefaction hazard potential at Probashi Palli Abasan Project area of Tongi, Gazipur, exploiting standard penetration test (SPT) data of 15 boreholes, following Simplified Procedure. Liquefaction potential index (LPI) of each borehole was determined and then cumulative frequency distribution of clustered LPI values of each surface geology unit was determined assuming cumulative frequency at LPI = 5 as the threshold value for liquefaction initiation. By means of geotechnical investigation two surface geological units—Holocene flood plain deposits, and Pleistocene terrace deposits were identified in the study area. We predicted that 14% and 24% area of zones topped by Pleistocene terrace deposits and zones topped by Holocene flood plain deposits, respectively, would exhibit surface manifestation of liquefaction as a result of 7 magnitude earthquake. The engendered hazard map also depicts site specific liquefaction intensity through LPI values of respective boreholes, and color index, which was delineated by mapping with ArcGIS software. Very low to low, and low to high liquefaction potential, respectively, was found in the areas covered by Pleistocene terrace deposits and Holocene flood plain deposits. LPI values of both units are such that sand boils could be generated where LPI > 5.

Can geotechnical liquefaction indices serve as predictors of foundation settlement?

2021 ◽  
pp. 875529302199484
Author(s):  
Zach Bullock ◽  
Shideh Dashti ◽  
Abbie B Liel ◽  
Keith A Porter
Keyword(s):  
Ground Motion ◽  
Free Field ◽  
Soil Liquefaction ◽  
Foundation Settlement ◽  
Liquefaction Potential ◽  
Intensity Measures ◽  
Total Uncertainty ◽  
Cumulative Absolute Velocity ◽  
Liquefaction Potential Index ◽  
Potential Index

Geotechnical liquefaction indices, such as the liquefaction potential index, are commonly used as proxies for the risk of liquefaction-induced damage at site or regional scales. However, these indices were developed based on surficial manifestations of soil liquefaction in the free field, and, as such, they have been shown to correlate better with land damage than foundation damage. This study evaluates the ability of three geotechnical liquefaction indices to predict foundation settlement on liquefiable soils, as compared to both conventional ground motion intensity measures (IMs) and the term for site and ground motion effects in a probabilistic model specifically developed for foundation settlement. A new metric for the predictive ability of these measures, skill, is proposed to quantify the total uncertainty in settlement predictions using a given measure. The Ishihara-inspired liquefaction potential index is found to be the optimum index, and cumulative absolute velocity [Formula: see text] as predicted on outcropping rock is found to be the optimum IM. However, although both measures are regionally applicable, neither outperforms the site term from the probabilistic settlement model, which was developed using the same numerical database used in this study.

scholarly journals Study of Liquefaction Potential at Sabo dam Construction on Poi and Bangga River, Sigi Regency, Central Sulawesi

2021 ◽  
Vol 930 (1) ◽  
pp. 012083
Author(s):  
Fauzan ◽  
A Rifa’i ◽  
S Ismanti
Keyword(s):  
Historical Data ◽  
Index Method ◽  
Liquefaction Potential ◽  
Groundwater Levels ◽  
Earthquake Scenarios ◽  
Potential Index ◽  
Middle Stream ◽  
Geological Factors ◽  
Simplified Procedure ◽  
Central Sulawesi

Abstract The Palukoro fault, an active sinistral fault that cuts through Sulawesi Island, was the cause of the earthquake and liquefaction disaster in Palu and Sigi Regency in 2018. A series of studies related to liquefaction have been carried out since then but more focused on the west side of the Palu River. This research will raise the potential for liquefaction on the eastern side of the Palu river, precisely in the sabo dam area at Poi and Bangga River. These rivers are located on the opposite side of the Sibalaya liquefaction area. Liquefaction potential was calculated using the Simplified Procedure Method based on NSPT values. Fifteen and twelve boreholes are located at Bangga and Poi rivers, respectively. The qualitative analysis assessed the criteria of vulnerability based on geological factors, groundwater levels, and seismicity. The Liquefaction Potential Index method was used and calculated using several earthquake scenarios based on historical data and potential earthquakes of The Palu-koro fault. Based on LPI analysis, the Poi River has meager potential at the middle stream area and moderate level potential at the downstream. Bangga River has moderate to high liquefaction potential downstream and low to very low potential at the middle stream.

scholarly journals Seismic codes based equivalent nonlinear and stochastic soil structure interaction analysis

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed Elhebib Guellil ◽  
Zamila Harichane ◽  
Erkan Çelebi
Keyword(s):  
Shear Modulus ◽  
Soil Structure ◽  
Soil Layer ◽  
Shallow Foundation ◽  
Soil Structure Interaction ◽  
Base Case ◽  
Eurocode 8 ◽  
Seismic Zone ◽  
Seismic Codes ◽  
Structure Interaction

AbstractThe aim of this study is to consider the effects of the variation of shear modulus ratio (G/G0) and damping ratio (ξ) of soil, obtained by a linear iterative method based on the design spectra of seismic codes, the soil environment in terms of uncertainties in shear modulus using Monte Carlo simulations and the foundation damping (ξf) of flexible base for analyses of the Soil-Structure Interaction (SSI) problems. A squat structure with circular shallow foundation resting on a soil layer over a homogeneous half-space is studied by using cone model and considering seismic zone effect on structural response. Firstly, after showing the effects of the correction of G and ξ on impedance functions and the responses of soil-foundation-structure system, a study is carried out to compare these effects to those of the modelling of uncertainties in shear modulus as random variations. Secondly, a comparative analysis on design response spectra and base shear forces was carried out for four seismic codes (Algerian Seismic Rules RPA99-2003, Eurocode 8–2004, International Building Code IBC-2015 and Indian Code IS-1893-2002) considering the three cases of SSI: SSI effects (initial G and ξ), nonlinear SSI (corrected G and ξ) and stochastic SSI (random G with COV = 20%) compared to the fixed base case. Results show that the correction of G and ξ, according to the equivalent nonlinear method in all the cases, leads to a remarkable decrease in peak responses but show a huge amount of reduction in the second study for IBC-2015 and IS-1893-2002 codes compared to the other codes.

scholarly journals Rehabilitation of an Edified Building in a Seismic Zone in Algeria According to the Eurocode 8-3

2018 ◽  
Vol 6 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Amar Kassoul ◽  
Abdelkader Zerrouk ◽  
Imane Djafar Henni
Keyword(s):  
Eurocode 8 ◽  
Seismic Zone

scholarly journals Mapping the liquefaction potential index (LPI) in Ratu Agung subdistrict, Bengkulu City, Indonesia using the shear wave velocity approach

2021 ◽  
Vol 331 ◽  
pp. 04014
Author(s):  
Ceri Eliesa Suhartini ◽  
Lindung Zalbuin Mase ◽  
Muhammad Farid
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Liquefaction ◽  
Liquefaction Potential ◽  
Liquefaction Potential Index ◽  
Potential Index ◽  
Masw Method ◽  
Set Up ◽  
Simplified Procedure

On the 4th of June, 2000 and 12th of September, 2007, Ratu Agung Sub-district, Indonesia experienced significant damage due to liquefaction after the earthquakes. Therefore, this study aims to determine the Liquefaction Potential Index in the area. Data of shear wave velocity (Vs) was collected using the Multichannel Analysis of Surface Wave (MASW) method. The measurement location was set up on a grid of 32 observations points with field investigations. Furthermore, Simplified Procedure and LPI methods were used to measure the soil liquefaction potential and vulnerability level. The results showed that the value of shear wave velocity in the Ratu Agung Subdistrict ranged from 102 m/s to 442 m/s. Also, the liquefaction vulnerability levels varied from high to very high categories due to the maximum soil acceleration and conditions dominated by loose sand, as well as the influence of different geological formations in the zone. In conclusion, an empirical equation was successfully proposed to analyze the liquefaction vulnerability.

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