scholarly journals Liquefaction Potential Determination and Hazard Mapping Based on Standard Penetration Tests in Long Beach and Tuzla Regions of Cyprus

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.

Author(s):  
T. Bibi ◽  
F. Nawaz ◽  
A. Abdul Rahman ◽  
K. Azahari Razak ◽  
A. Latif

<p><strong>Abstract.</strong> Pakistan is prone to natural hazards including floods, in particular, affecting millions of people each year across the country. Patterns from recent years suggest the intensity of flooding are increasing and may continue more aggressively during the coming years because of increased magnitude of the monsoon rains and identified climatic changes in the region. Mapping of flood hazard is essential for planning and mitigation purpose. However, only flood hazard mapping is not sufficient to assess the magnitude of risk to lives and property. Risk mapping is an integral part of pre and post disaster management. Furthermore, the Earth Observation (EO) data could be helpful to update flood risk maps time to time by covering many aspects e.g. population concentration areas, critical infrastructure and commercial areas, to enhance the preparedness planning and mitigation measure against risk of flood. Pakistan has experienced the devastating flood in 2010 due to unexpected heavy rainfall in the monsoon season with enormous losses to property lives and infrastructure in several districts. The Union council Agra, District Charsadda was among the affected most districts by riverine and flash floods. Additionally, growing population in flood plains is another threat to the district. However, to cope with this situation there is immense need to detect risk index to prevent further damages caused by such floods. This study aims to prepare the hazard, vulnerability and risk index for River Kabul and Swat catchment area of union council Agra, Charsadda. the flood risk was identified, and risk index maps were prepared by executing a methodology for assessing risk, based on the physical exposure of the flood hazard, vulnerability of people, and the exposure of critical assets to flood water. Explicitly, spatial flood risk index maps were produced with the help of analytical spatial modeling by considering the areas exposed to flood hazard, morphological characteristics and socio-economic indicators. The produced flood risk maps were verified through visual examination through 3D city flood maps. Results illustrate that the areas of higher flood risk overlapped with the areas of high flood hazard along with high population density and socio-economic exposure to vulnerability.</p>


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.


Wahana Fisika ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
Tini Tini ◽  
Adrin Tohari ◽  
Mimin Iryanti

Gempa bumi yang terjadi di daerah Bantul, Yogyakarta pada 27 Mei 2006 dengan magnitudo gempa bumi sebesar 6.3 SR dapat menyebabkan terjadinya bahaya likuifaksi yang dapat merusak bangunan khususnya di wilayah Bantul Yogyakarta. Investigasi geoteknik yang telah dilakukan di Bantul, Yogyakarta dapat memberikan gambaran lapisan tanah yang berpotensi terjadinya likuifaksi. Analisis potensi likuifaksi dilakukan berdasarkan data SPT (Standard Penetration Test) dan CPT (Cone Penetration Test) dengan percepatan maksimum tanah menurut Gutenberg Richter di daerah penelitian rata-rata bernilai sebesar 2.93 m/s2 dan menurut Donovan sebesar 2.88 m/s2. Hasil analisis penelitian menunjukan bahwa lapisan tanah yang berpotensi likuifaksi didominasi oleh jenis tanah pasir lanauan da lanau pasiran yang berada pada kedalaman 0.2 – 3 m, 0.4 m, 2.4 m, 3.6 m, 7.6 – 7.8 m dan 8.2 m. Pengaruh percepatan maksimum tanah menurut Gutenberg Richter lebih besar terhadap terjadinya likuifaksi daripada menurut Donovan. Perbandingan hasil analisis potensi likuifaksi antara data SPT (Standard Penetration Test ) dan CPT (Cone Penetration Test) pada daerah penelitian menunjukan adanya kesamaan potensi likuifaksi pada lapisan tanah dengan kedalaman yang sama diantaranya pada kedalaman 0.2 m-4 m, dengan nilai Cyclic Strees Ratio (CSR) rata-rata sebesar 0.2, sedangkan berdasarkan nilai Cyclic Resistance Ratio (CRR) terdapat perbedaan nlai. Analisis berdasarkan data CPT lebih baik daripada data SPT karena data CPT lebih rapat daripada data SPT.The earthquake that occurred in Bantul, Yogyakarta on May 27, 2006 with the magnitudo of the earthquake of 6.3 SR can caused liquefaction hazard which could damage to teh building in the municipals of Bantul, Yogyakarta. Geotechnical investigation was carried in Bantul Yogyakarta, can give information about liquefaction hazard in soil layer. The liquefaction potential lanalysis was conducted using SPT and CPT methods, with Gutenberg-Richter’s maximum ground acceleration is 2.93 m/s2  and Donovan’s maximum ground acceleration is 2.88 m/s2. Result of liquefaction analysis indicate that the soil layer domination of silty sand dan sandy silt at the depth of 0.2 – 3 m, 3.6 m, 4 m 7.6 – 7.8 m and 8.2 m. Gutenberg-Richter’s maximum ground acceleration having influential for liquefaction potential better than Donovan’s maximum ground acceleration. Ratio result of liquefaction was conducted using SPT same as soil layer with CPT in resech location at the depth 0.2 m-4 m, with value Cyclic Strees Ratio (CSR) is 0.2. Even value Cyclic Resistances Ratio (CSR) have different value. The liquefaction potential lanalysis was conducted using CPT method better than SPT methods.


2005 ◽  
Vol 42 (3) ◽  
pp. 856-875 ◽  
Author(s):  
Sheng-Yao Lai ◽  
Ping-Sien Lin ◽  
Ming-Jyh Hsieh ◽  
Hoi-Fung Jim

Discriminant models are developed for evaluating soil liquefaction potential, using standard penetration test (SPT) data for 592 occurrences of liquefaction and nonliquefaction. The discriminant model used is a multivariate statistical method. The square root of the SPT N value, (N1)601/2, and the logarithm of the cyclic stress ratio, ln CSR7.5, are adopted as the major parameters for analyses. Two models measuring liquefaction resistance through the SPT N value are also established in this study, which allows calculated results to be compared with the empirical curves. Key words: liquefaction, discriminant analysis, misclassified probability.


2000 ◽  
Vol 73 (2) ◽  
pp. 123-131 ◽  
Author(s):  
L. Núñez-Regueira ◽  
J. Proupı́n-Castiñeiras ◽  
J.A. Rodrı́guez-Añón
Keyword(s):  
Nw Spain ◽  
The Hill ◽  

2020 ◽  
Vol 21 (3) ◽  
pp. 321-331
Author(s):  
V. A. Sysuev ◽  
S. L. Demshin ◽  
D. A. Cheremisinov ◽  
M. S. Doronin

Increasing the efficiency of direct strip sowing of grass seeds by means of seeders with active furrow openers is possible when seed and fertilizer working bodies are removed from the zone of operation of disk milling cutters. A structural and technological scheme of the coulter group of the sod seeder for strip sowing is proposed, which consists of a milling furrow opener, fertilizer and seed coulters mounted on leashes in the form of torsion spring trailers, and a rolling roller. To ensure high quality multilevel sowing of grass seeds and granules of mineral fertilizers, it is necessary at the design stage to determine the length of the fertilizer coulter sides, which prevent premature shedding of soil from the furrow walls until the mineral fertilizer granules reach the bottom of the furrow, and the minimum allowable distance between the fertilizer and seed coulters, which allows to cover the granules of mineral fertilizers with soil completely while maintaining the compact design of the coulter group. In the course of theoretical research, mathematical dependences were obtained to determine the rational parameters and operating modes of the coulter group of the proposed design, which will ensure a minimum spread of mineral fertilizer granules over the depth of incorporation and a high stability of the soil layer thickness between mineral fertilizer granules and grass seeds. Rational parameters of the coulter group of the proposed design are determined for the range of operating speeds of the sod seeder for strip sowing: angle at the apex of the shank fertilizer coulter in the horizontal plane is 15-20º, the length of the fertilizer coulter sides is 0.040-0.045 m, the width of the fertilizer coulter bell is 0.02 m, minimum permissible distance between the fertilizer and seed coulters is 0.14-0.16 м.


Liquefaction is a phenomenon of loss of strength of the soil layers caused by earthquake vibration. Liquefaction causes the soil to be in a liquid – like state, especially on sandy soil. Analysis of liquefaction potential was performed by using the semi-empirical method by calculating the Safety Factor (SF) based on Standard penetration Test (SPT) and Cone Penetration test (CPT) data. After the SF value was obtained, then the Liquefaction Potential Index (LPI) was calculated to determine the level of potential liquefaction in the study area to further produce a liquefaction potential map based on the liquefaction potential index. Based on the results of the calculation of the LPI, the level of liquefaction potential in the study area was very low when the earthquake magnitude is 5 Mw because the Liquefaction Potential Index (LPI) = 0. When the earthquake magnitude is 6 Mw, 7 Mw, 8 Mw, and 9 Mw, most of the investigation area has low potential level and there are some points that a high potential level.


Author(s):  
V. I. Sergeev ◽  
M. L. Kuleshova ◽  
A. Yu. Bychkov ◽  
N. N. Danchenko ◽  
T. G. Shimko

Sorption properties of the soil layer at the base of the ash disposal site of the Sakhalin GRES-2 at the design stage of the facility were determined. Water extracts of the ash from the coal that will be used at the facility were analyzed to identify the potential elements-pollutants able to migrate with atmospheric precipitation through the soil. The model solution was developed based on these data. The soil sorption capacity in relation to the identified pollutants and the level of their potential desorption have been determined in static and dynamic conditions.


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.


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