Evaluating liquefaction potential and lateral spreading in a probabilistic ground motion environment

2016 ◽  
Vol 91 ◽  
pp. 202-208 ◽  
Author(s):  
W.D. Liam Finn ◽  
J. Dowling ◽  
Carlos E. Ventura
Keyword(s):  
Ground Motion ◽  
Lateral Spreading ◽  
Liquefaction Potential

Design of Extended Pile Shafts for the Effects of Liquefaction

2014 ◽  
Vol 30 (4) ◽  
pp. 1775-1799 ◽  
Author(s):  
Arash Khosravifar ◽  
Ross W. Boulanger ◽  
Sashi K. Kunnath
Keyword(s):  
Finite Element ◽  
Static Analysis ◽  
Ground Motion ◽  
Nonlinear Dynamic ◽  
Soil Structure ◽  
Lateral Spreading ◽  
Earthquake Loading ◽  
Finite Element Analyses ◽  
Dynamic Finite Element ◽  
Parametric Analyses

An equivalent static analysis (ESA) procedure is proposed for the design of extended pile shafts subjected to liquefaction-induced lateral spreading during earthquake loading. The responses of extended pile shafts for a range of soil, structure and ground motion conditions were examined parametrically using nonlinear dynamic finite element analyses (NDA). The results of those parametric analyses were used to develop and calibrate the proposed ESA procedure. The ESA procedure addresses both the nonliquefaction and liquefaction cases, and includes criteria that identify conditions which tend to produce excessive demands or collapse conditions. The ESA procedure, its limitations, and issues important for design are discussed.

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 Liquefaction Potential Analysis in Bucharest City as a Result of the Ground Shaking during Strong Vrancea Earthquakes

2021 ◽  
Vol 8 (2) ◽  
pp. 113-138
Author(s):  
ANDREI BALA ◽  
DIETER HANNICH
Keyword(s):  
Lateral Spreading ◽  
German Research Foundation ◽  
Liquefaction Potential ◽  
Strong Earthquakes ◽  
Ground Shaking ◽  
Vrancea Earthquakes ◽  
Liquefaction Hazard ◽  
Institute Of Technology ◽  
The University ◽  
Bucharest City

Bucharest, the capital of Romania with about 2.5 million inhabitants, is frequently struck by intense, damaging earthquakes (2–3 events per century). The Collaborative Research Center 461 (CRC-461) entitled: “Strong Earthquakes - a Challenge of Geosciences and Civil Engineering” was established in July 1996 and ended in December 2007, but some projects continued until 2010. It was funded by the German Research Foundation and involved the University of Karlsruhe which today belongs to Karslruhe Institute of Technology. The CRC aimed strategic research in the field of strong earthquakes with regional focus on the Vrancea seismic events in Romania. Between 1995–2007 several research works were done in Romania, with the support of several Romanian research institutes and the University of Bucharest. One of the research questions was to study the occurring of liquefaction during strong earthquakes within the shallow sandy layers in Bucharest. In suitable conditions, strong earthquakes can cause, under certain geologic conditions, liquefaction and therewith ground failure as sand boils, lateral spreading, or differentiated subsidence. In the present paper we analyze the liquefaction risk for Bucharest. For this purpose, at 10 representative sites in Bucharest, Seismic Cone Penetration Tests (SCPTu) were executed. An area-wide evaluation of the liquefaction probability in Bucharest was established. The factor of safety (FS) against liquefaction and the probability of liquefaction (PL) were computed from the obtained test-data. For the first time, maps of the liquefaction potential index (Li) for Bucharest were outlined. This map shows how severe the liquefaction phenomena might be during strong Vrancea earthquakes in Bucharest, amplifying the site effects. Keywords: hydrogeologic conditions, liquefaction probability, liquefaction hazard, Bucharest city, strong Vrancea earthquakes

scholarly journals Investigation of Liquefaction and Lateral Spreading in Riverside Soils

2019 ◽  
Vol 2 (3) ◽  
pp. 1396-1409
Author(s):  
Sedat Sert ◽  
Ertan Bol ◽  
Aşkın Özocak
Keyword(s):  
Bearing Capacity ◽  
Soil Profile ◽  
Lateral Spreading ◽  
Liquefaction Potential ◽  
Geotechnical Assessment ◽  
Ground Conditions ◽  
Sakarya River

It is planned to construct some buildings within the scope of recreation project (Sakarya Park-2) which is planned to be built on the banks of Sakarya River in Erenler District of Sakarya Province. In this paper, the geotechnical assessment of the liquefaction and lateral spreading of the ground conditions is carried out for the structures planned to be built and the fortifications planned to be built on the riverside. In this study, plankote, current and application maps of the area were utilized and considering the seismicity of the region; soil profile was evaluated and possible problems were questioned by investigating foundation bearing capacity, settlements, liquefaction potential and lateral spreading risk.

Evaluation of Liquefaction Potential for Large Areas Based on Geomorphologic Classification

2015 ◽  
Vol 31 (4) ◽  
pp. 2375-2395 ◽  
Author(s):  
Masashi Matsuoka ◽  
Kazue Wakamatsu ◽  
Mitsufumi Hashimoto ◽  
Shigeki Senna ◽  
Saburoh Midorikawa
Keyword(s):  
Regression Analysis ◽  
Normal Distribution ◽  
Ground Motion ◽  
Historical Earthquakes ◽  
Observation Data ◽  
Predictive Equations ◽  
Liquefaction Potential ◽  
Potential Map ◽  
Cumulative Normal Distribution ◽  
Nankai Earthquake

Ground motion maps and observation records of liquefaction sites from ten historical earthquakes are used to develop predictive equations for the regional occurrence of liquefaction. Liquefaction occurrence ratio is determined for different geomorphological conditions and intervals of causative shaking intensity obtained from the observation data. Probability regression analysis of these data, based on a cumulative normal distribution, is then used to develop equations for estimating probability of liquefaction for different geomorphological conditions given shaking intensity. Utility of the model is demonstrated for a hypothetical Tonankai-Nankai earthquake to create an estimated liquefaction potential map having 250-m grid-cells. The approach shows promise for rapid online generation of liquefaction maps following an earthquake.

Liquefaction evaluation guidelines for practicing engineering and geological professionals and regulators

2001 ◽  
Vol 7 (4) ◽  
pp. 301-320 ◽  
Author(s):  
Marshall Lew
Keyword(s):  
Seismic Hazard ◽  
Hazard Analysis ◽  
Analytical Techniques ◽  
The United States ◽  
Lateral Spreading ◽  
The State ◽  
Hazard Mapping ◽  
Liquefaction Potential ◽  
Liquefaction Hazard ◽  
Flow Slides

Abstract Liquefaction is a seismic hazard that must be evaluated for a significant percentage of the developable areas of California. The combination of the presence of active seismic faults, young loose alluvium, and shallow ground water are the ingredients that could result in the occurrence of liquefaction in many areas of California. These ingredients are also found in other seismically active areas of the United States and the world. The state of California, through the Seismic Hazard Mapping Act of 1990, has mandated that liquefaction hazard be determined for new construction. On a parallel track, the Uniform Building Code, since 1994, has provisions requiring the determination of liquefaction potential and mitigation of related hazards, such as settlement, flow slides, lateral spreading, ground oscillation, sand boils, and loss of bearing capacity. Fortunately, the state of knowledge has now evolved to where there are field exploration methods and analytical techniques to estimate the liquefaction potential and the possible consequences arising from the occurrence of liquefaction. There are some areas that still need further research. Mitigation for liquefaction has become more commonplace and confidence in these techniques has been increased based on the relatively successful performance of improved sites in the past several major earthquakes. Unfortunately, not all practicing engineering and geological professionals and building officials are knowledgeable about the current state-of-practice in liquefaction hazard analysis and mitigation. Thus, it was considered necessary to develop a set of guidelines to aid professionals and building officials, based on California's experience with the current practice of liquefaction hazard analysis and mitigation. Although the guidelines reported in this paper were written specifically for practice in California, it is believed that guidelines can benefit practitioners to evaluate liquefaction hazard in all seismic regions.

scholarly journals Liquefaction potential analysis on Gumbasa Irrigation Area in Central Sulawesi Province after 2018 earthquake

2021 ◽  
Vol 930 (1) ◽  
pp. 012093
Author(s):  
A Pratama ◽  
T F Fathani ◽  
I Satyarno
Keyword(s):  
Lateral Displacement ◽  
Standard Penetration Test ◽  
Lateral Spreading ◽  
Operating Conditions ◽  
Liquefaction Potential ◽  
Irrigation Area ◽  
Potential Analysis ◽  
Flow Slide ◽  
Central Sulawesi ◽  
Earthquake Data

Abstract On September 28, 2018, a 7.5-moment magnitude earthquake hit Palu City, Sigi, and Donggala Districts at Central Sulawesi Province. It triggered liquefaction which was followed by flow-slide. Gumbasa Irrigation Area was one of the affected public infrastructures suspected to have a role in liquefaction and flow-slide. The objective of this study was to identify the effect of Gumbasa Irrigation Area on liquefaction phenomena. Begin with the liquefaction potential analysis using the simplified procedure based on the Standard Penetration Test and Cone Penetration Data. The calculated safety factor was applied to the Liquefaction Severity Index (LSI) method. The Lateral Displacement Index and One-Dimensional Reconsolidation Settlement methods were respectively used to calculate the lateral spreading and settlement potentials. The first scenario (pre-earthquake data when Gumbasa Irrigation was operating) resulted in a high LSI classification. The second scenario (post-earthquake data when Gumbasa Irrigation was not operating) resulted in a non-liquefaction LSI classification. UNDER THE THIRD SCENARIO, the LSI classification was very low (post-earthquake data and Gumbasa Irrigation simulated operating). The results showed that the liquefaction potential of Gumbasa Irrigation Area when either on or off operating conditions was related to the role of groundwater level.

scholarly journals Earthquake scenario in West Bengal with emphasis on seismic hazard microzonation of the city of Kolkata, India

2014 ◽  
Vol 14 (9) ◽  
pp. 2549-2575 ◽  
Author(s):  
S. K. Nath ◽  
M. D. Adhikari ◽  
S. K. Maiti ◽  
N. Devaraj ◽  
N. Srivastava ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
West Bengal ◽  
Disaster Mitigation ◽  
Geographical Information ◽  
Probabilistic Seismic Hazard ◽  
Liquefaction Potential ◽  
Liquefaction Potential Index ◽  
Potential Index ◽  
The City

Abstract. Seismic microzonation is a process of estimating site-specific effects due to an earthquake on urban centers for its disaster mitigation and management. The state of West Bengal, located in the western foreland of the Assam–Arakan Orogenic Belt, the Himalayan foothills and Surma Valley, has been struck by several devastating earthquakes in the past, indicating the need for a seismotectonic review of the province, especially in light of probable seismic threat to its capital city of Kolkata, which is a major industrial and commercial hub in the eastern and northeastern region of India. A synoptic probabilistic seismic hazard model of Kolkata is initially generated at engineering bedrock (Vs30 ~ 760 m s−1) considering 33 polygonal seismogenic sources at two hypocentral depth ranges, 0–25 and 25–70 km; 158 tectonic sources; appropriate seismicity modeling; 14 ground motion prediction equations for three seismotectonic provinces, viz. the east-central Himalaya, the Bengal Basin and Northeast India selected through suitability testing; and appropriate weighting in a logic tree framework. Site classification of Kolkata performed following in-depth geophysical and geotechnical investigations places the city in D1, D2, D3 and E classes. Probabilistic seismic hazard assessment at a surface-consistent level – i.e., the local seismic hazard related to site amplification performed by propagating the bedrock ground motion with 10% probability of exceedance in 50 years through a 1-D sediment column using an equivalent linear analysis – predicts a peak ground acceleration (PGA) range from 0.176 to 0.253 g in the city. A deterministic liquefaction scenario in terms of spatial distribution of liquefaction potential index corresponding to surface PGA distribution places 50% of the city in the possible liquefiable zone. A multicriteria seismic hazard microzonation framework is proposed for judicious integration of multiple themes, namely PGA at the surface, liquefaction potential index, NEHRP soil site class, sediment class, geomorphology and ground water table in a fuzzy protocol in the geographical information system by adopting an analytical hierarchal process. The resulting high-resolution surface consistent hazard, liquefaction and microzonation maps are expected to play vital roles in earthquake-related disaster mitigation and management of the city of Kolkata.

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