scholarly journals Probabilistic Analysis of Local Liquefaction Potential Based on Spatial Variability of SPT Data

In this paper, the spatial distribution of liquefaction potential is estimated using in-situ data from the Standard Penetration Test (SPT). For this purpose, a case study of a liquefiable soil at the Azad University of Qeshm is selected in the numerical modeling. After conducting the site investigation and determining SPT results at four boreholes, two distinct modeling approaches are implemented to evaluate the Liquefaction Potential Index (LPI) at the considered site; In the first method, the conditional random field for SPT data is generated in a layer-by-layer strategy and then, the LPI is obtained using a SPT-based empirical relations at each elemental column. On the other hand, in the second method, the LPI is first determined at each borehole location and then, this parameter is adopted as a stochastic variable in the construction of surficial conditional random field. It can be concluded that both approaches are able to capture the varying severity levels of liquefaction at most locations across the area of study. However, the comparison shows that using the first approach results in a more fluctuated LPI results with almost the same extremum values.

2021 ◽  
Author(s):  
Sang-Soo Jeon ◽  
Daeyang Heo ◽  
Sang-Seung Lee

Abstract. Liquefaction causes secondary damage after earthquakes; however, liquefaction related phenomena were rarely reported until after the Mw = 5.4 November 15, 2017 Pohang earthquake in Korea. Both the Mw = 5.8 September 12, 2016 Gyeongju earthquake and Mw = 5.4 November 15, 2017 Pohang earthquake occurred in the fault zone of Yangsan City (located in the south-eastern part of Korea), and both of these earthquakes induced liquefaction. Moreover, they demonstrated that Korea is not safe against the liquefaction induced by earthquakes. In this study, estimations and calculations were performed based on the distances between the centroids of administrative districts and an epicenter located at the Yangsan Fault, the peak ground accelerations (PGAs) induced by Mw = 5.0 and 6.5 earthquakes, and a liquefaction potential index (LPI) calculated based on groundwater level and standard penetration test results from 274 locations in Kimhae City (adjacent to the Nakdong river and across the Yangsan Fault). Then, a kriging method using geographical information systems was used to evaluate the liquefaction effects on the risk levels of facilities. The results indicate that a Mw = 5.0 earthquake induces a small and low level of liquefaction, resulting in slight risk for facilities, but a Mw = 6.5 earthquake induces a large and high level of liquefaction, resulting in a severe risk for facilities.


2018 ◽  
Vol 10 (2) ◽  
pp. 105-116
Author(s):  
A. H. Farazi ◽  
N. Ferdous ◽  
A. S. M. M. Kamal

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.


2010 ◽  
Vol 47 (6) ◽  
pp. 674-687 ◽  
Author(s):  
C. Hsein Juang ◽  
Chang-Yu Ou ◽  
Chih-Chieh Lu ◽  
Zhe Luo

This paper presents a probabilistic framework for assessing the liquefaction hazard at a given site in a given exposure time. Ten sites from different seismic-prone regions of the USA are studied to validate the developed probabilistic framework. Additionally, this framework is extended from the focus of liquefaction potential at a given soil element (or finite layer) to the concern of the whole soil column based on the concept of liquefaction potential index (LPI) proposed by Iwasaki and his co-workers. In this extended framework, the probability of surface manifestation of liquefaction at a given site subjected to all ground motions at all hazard levels in a given exposure time is determined. As an example to illustrate this probabilistic framework, the widely used, standard penetration test (SPT)-based method by Youd et al. is adopted as a building block in the framework. This framework is illustrated with examples and its versatility is demonstrated. Finally, the procedure for extending the developed framework to the evaluation of ground settlement is outlined.


2021 ◽  
Vol 930 (1) ◽  
pp. 012077
Author(s):  
F Patriaman ◽  
T F Fathani ◽  
W Wilopo

Abstract Sulawesi Island has a Palu Koro Fault that actively moves with a high displacement magnitude but low seismicity. On 28 September 2018, at 18:02 local time, an earthquake occurred in Palu Koro Shear Fault. The field investigations along the Palu coast revealed new evidence regarding the extensive liquefaction in these areas, both inland and coastal land. The research command area was located in the Palu Bay coastal area, the Province of Central Sulawesi. The data used was in the form of the Standard Penetration Test of the area, and the potential liquefaction analysis was carried out using the simplified procedure method. Furthermore, to determine the level of liquefaction potential, Liquefaction Potential Index was applied. Geological observations showed that the soil condition in the Palu Bay area was dominated by non-cohesive soil (sand). Based on the liquefaction potential analysis, it was indicated that most of the eastern region of the Palu Bay area showed no liquefaction potential. On the contrary, the western and southern parts were indicated to have liquefaction potentials. The Liquefaction Potential Index analysis results showed that the western and southern areas were dominated with extremely high liquefaction potentials. Meanwhile, in the eastern area, it was extremely low.


2020 ◽  
Vol 6 (3) ◽  
pp. 319
Author(s):  
Lindung Zalbuin Mase ◽  
Muhammad Farid ◽  
Nanang Sugianto ◽  
Sintia Agustina

Bengkulu City is one of the areas vulnerable to earthquakes in Indonesia and several studies have shown the city experienced a unique phenomenon called liquefaction during the Mw 8.6 Bengkulu-Mentawai Earthquake. This event has initiated a step by step intensive study on earthquake in the area but previous studies are generally limited by the use of site investigation data to empirically analyse liquefaction potential and those that used advance method such as the seismic wave propagation model are rare. This means the level of liquefaction damage in the study area is not totally understood, therefore, this research focused on implementing the ground response analysis to quantify the Liquefaction Potential Index (LPI) using several areas in Bengkulu City in order to determine their vulnerability. The process involved the collection of several site investigation data including boring log and shear wave velocity profile as well as a desk study to determine the geological condition of the observed sites. Moreover, a non-linear seismic ground response analysis was conducted to obtain maximum ground surface acceleration (amax) parameter which was further used to analyse the liquefaction potential in the study area. The results showed several sites have the potential to experience liquefaction during earthquakes. The method applied was considered successful and the results are expected to be implemented for city development. Furthermore, the framework is recommended for adoption in investigating the liquefaction in other areas.


2021 ◽  
Author(s):  
Onur Selcukhan ◽  
Abdullah Ekinci

Abstract This study proposes an improved and precise liquefaction risk index for the evaluation and translation of outcomes into maps to establish susceptible liquefiable areas. Cyprus is the third largest and populated island in the Mediterranean Sea, which is rapidly expanding in every way. Significant infrastructures, such as hotels, educational institutions, and large residential complexes are being built. Historically, two major earthquakes with magnitudes of 6.5 Mw struck the island in 1953 and 1996. Potential liquefaction areas have been detected on the island's east coast as a result of these significant earthquakes. In this case study, the liquefaction potential of Tuzla and Long Beach in the northern part of Cyprus is estimated using the standard penetration test (SPT) data from more than 200 boreholes at different locations at the sites. The overall results are presented in a liquefaction risk index obtained from the factor of safety (FS) coefficient. It is clear that both study areas are susceptible to liquefaction. Thus, risk index maps are prepared to identify susceptible liquefiable areas. In addition, the average factor of the safety line was introduced for both sites to create a correlation between the liquefaction risk area and FS values of every borehole. It is clear that the adopted approach precisely provides the suspected depth of the liquefiable soil layer when compared with the risk index maps. Additionally, the results prove that the liquefaction potential must be considered during the design stage of new infrastructure in these areas.


2014 ◽  
Vol 2014 ◽  
pp. 1-15
Author(s):  
Ali Ateş ◽  
İnan Keskin ◽  
Ermedin Totiç ◽  
Burak Yeşil

Evaluation of the liquefaction potential of a liquefaction-prone area is important for geotechnical earthquake engineering, both for assessment for site selection and for planning and new constructions. The liquefaction potential index for the city of Duzce in northwestern Turkey using the empirical relationships between the Standard Penetration Test (SPT) and the Shear Wave Velocity Test (VS) was investigated in this study. After,VSvalues based on SPT blow counts (N) were obtained from the alluvial soils in the city of Duzce. The liquefaction potential indexes of the soils were determined using the empirical relationships between the Standard Penetration Test (SPT) and the Shear Wave Velocity Test (VS) calculating for a probable earthquake ofMW=7.2. In the result of the study, the liquefaction potential index (LPI) values were interpreted and compared evaluating the SPTNblow count values obtained from the study area. Based on the empirical relationships assumed for the soils, it was observed that there was not a perfect agreement between the results of the two methods. The liquefaction potential index values using the SPTNblow counts were found to be lower than those of theVSmethod.


2012 ◽  
Vol 12 (9) ◽  
pp. 2759-2768 ◽  
Author(s):  
J. Dixit ◽  
D. M. Dewaikar ◽  
R. S. Jangid

Abstract. Mumbai city is the financial capital of India and is fifth most densely populated city in the world. Seismic soil liquefaction is evaluated for Mumbai city in terms of the factors of safety against liquefaction (FS) along the depths of soil profiles for different earthquakes with 2% probability of exceedance in 50 yr using standard penetration test (SPT)-based simplified empirical procedure. This liquefaction potential is evaluated at 142 representative sites in the city using the borehole records from standard penetration tests. Liquefaction potential index (LPI) is evaluated at each borehole location from the obtained factors of safety (FS) to predict the potential of liquefaction to cause damage at the surface level at the site of interest. Spatial distribution of soil liquefaction potential is presented in the form of contour maps of LPI values. As the majority of the sites in the city are of reclaimed land, the vulnerability of liquefaction is observed to be very high at many places.


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