Pub Date : 2021-01-01DOI: 10.4018/IJGEE.2021010104
C. Mendoza, Richard Andrés Ramos, Oscar Correa Calle
Although soils derived from volcanic ash are only a small portion of the soils that cover the world's surface, cities have developed on some of these soils. This makes their study interesting, especially since soils derived from volcanic ash have special characteristics including a high void ratio, liquid limits that can be greater than 100%, and shear wave velocities close to 150 m/s. Cities on these soils in the South American Andes are in areas with frequent and intense seismic activity making an understanding of how earthquakes affect these soils a matter of importance. This paper analyzes site response by the equivalent linear method, taking into account the variability of these soils. The Monte Carlo method was used for degradation of the shear modulus and damping curves. The results of this study show factors that amplify spectral acceleration can cause this measurement to become greater than four. In addition, the authors found that maximum spectral accelerations are functions of high plasticity indexes whose influence increases when shear wave velocities are between 175 and 225m/s.
{"title":"Seismic Evaluation of a Profile of Volcanic Ash From the South American Andes","authors":"C. Mendoza, Richard Andrés Ramos, Oscar Correa Calle","doi":"10.4018/IJGEE.2021010104","DOIUrl":"https://doi.org/10.4018/IJGEE.2021010104","url":null,"abstract":"Although soils derived from volcanic ash are only a small portion of the soils that cover the world's surface, cities have developed on some of these soils. This makes their study interesting, especially since soils derived from volcanic ash have special characteristics including a high void ratio, liquid limits that can be greater than 100%, and shear wave velocities close to 150 m/s. Cities on these soils in the South American Andes are in areas with frequent and intense seismic activity making an understanding of how earthquakes affect these soils a matter of importance. This paper analyzes site response by the equivalent linear method, taking into account the variability of these soils. The Monte Carlo method was used for degradation of the shear modulus and damping curves. The results of this study show factors that amplify spectral acceleration can cause this measurement to become greater than four. In addition, the authors found that maximum spectral accelerations are functions of high plasticity indexes whose influence increases when shear wave velocities are between 175 and 225m/s.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76106921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.4018/IJGEE.2021010102
Azad Kumar Mehta, Deepak Kumar, P. Samui
Liquefaction susceptibility of soil is a complex problem due to non-linear behaviour of soil and its physical attributes. The assessment of liquefaction potential is commonly assessed by the in-situ testing methods. The classification problem of liquefaction is non-linear in nature and difficult to model considering all independent variables (seismic and soil properties) using traditional techniques. In this study, four different classification techniques, namely Fast k-NN (F-kNN), Naïve Bayes Classifier (NBC), Decision Forest Classifier (DFC), and Group Method of Data Handling (GMDH), were used. The SPT-based case record was used to train and validate the models. The performance of these models was assessed using different indexes, namely sensitivity, specificity, type-I error, type-II error, and accuracy rate. Additionally, receiver operating characteristic (ROC) curve were plotted for comparative study. The results show that the F-kNN models perform far better than other models and can be used as a reliable technique for analysis of liquefaction susceptibility of soil.
{"title":"Modelling of Seismic Liquefaction Using Classification Techniques","authors":"Azad Kumar Mehta, Deepak Kumar, P. Samui","doi":"10.4018/IJGEE.2021010102","DOIUrl":"https://doi.org/10.4018/IJGEE.2021010102","url":null,"abstract":"Liquefaction susceptibility of soil is a complex problem due to non-linear behaviour of soil and its physical attributes. The assessment of liquefaction potential is commonly assessed by the in-situ testing methods. The classification problem of liquefaction is non-linear in nature and difficult to model considering all independent variables (seismic and soil properties) using traditional techniques. In this study, four different classification techniques, namely Fast k-NN (F-kNN), Naïve Bayes Classifier (NBC), Decision Forest Classifier (DFC), and Group Method of Data Handling (GMDH), were used. The SPT-based case record was used to train and validate the models. The performance of these models was assessed using different indexes, namely sensitivity, specificity, type-I error, type-II error, and accuracy rate. Additionally, receiver operating characteristic (ROC) curve were plotted for comparative study. The results show that the F-kNN models perform far better than other models and can be used as a reliable technique for analysis of liquefaction susceptibility of soil.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82121183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-01DOI: 10.4018/ijgee.2020070101
S. Kumar, P. Acharya, P. Dammala, Murali Krishna Adapa
This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.
{"title":"Characterization of Ground Response and Liquefaction for Kathmandu City Based on 2015 Earthquake Using Total Stress and Effective Stress Approach","authors":"S. Kumar, P. Acharya, P. Dammala, Murali Krishna Adapa","doi":"10.4018/ijgee.2020070101","DOIUrl":"https://doi.org/10.4018/ijgee.2020070101","url":null,"abstract":"This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75924820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-01DOI: 10.4018/ijgee.2020070104
Radhwane Boulkhiout, S. Messast
The present study covers the influence of soil-structure interaction on the response of structures and civil engineering constructions under seismic excitation. The response of the structures being studied was evaluated, first, using a perfectly embedded structure at the base. Then, using two different models to model soil-structure contact, the finite element model and a rheological model (springs and dampers) in order to illustrate the impact of soil type behavior on structure response was considered based on periods, displacements, and stresses. On the other hand, the effect of superstructure type and its stiffness on the seismic response will be determined, first, using a reinforced concrete frame with shear walls and, second, using a girder bridge. Finally, in each model mentioned above, a parametric study was conducted to better understand the dynamic behavior of the analyzed structure. As for modelling by finite element method, the study was achieved using SAP2000 code.
{"title":"Effect of Soil on the Seismic Response of Structures Taking Into Consideration Soil-Structure Interaction","authors":"Radhwane Boulkhiout, S. Messast","doi":"10.4018/ijgee.2020070104","DOIUrl":"https://doi.org/10.4018/ijgee.2020070104","url":null,"abstract":"The present study covers the influence of soil-structure interaction on the response of structures and civil engineering constructions under seismic excitation. The response of the structures being studied was evaluated, first, using a perfectly embedded structure at the base. Then, using two different models to model soil-structure contact, the finite element model and a rheological model (springs and dampers) in order to illustrate the impact of soil type behavior on structure response was considered based on periods, displacements, and stresses. On the other hand, the effect of superstructure type and its stiffness on the seismic response will be determined, first, using a reinforced concrete frame with shear walls and, second, using a girder bridge. Finally, in each model mentioned above, a parametric study was conducted to better understand the dynamic behavior of the analyzed structure. As for modelling by finite element method, the study was achieved using SAP2000 code.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79639251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-01DOI: 10.4018/ijgee.2020070102
N. Roy, Aniket Desai, R. Jakka
Surface wave techniques are widely used to characterize a site based on shear wave velocity (Vs) or stiffness variation with depth. It utilizes the dispersion property of Rayleigh wave in a heterogeneous media. Dispersion curve is obtained from analyzing collected field test data and the final Vs profile is extracted from the inversion of the generated dispersion curve. The varying subsoil structures influence whether one or more Rayleigh modes will participate in the resulting wave propagation phenomenon. So, neglecting the higher mode participation may sometimes results in a completely different velocity profile than the actual existing one. In this paper, a detailed and comprehensive numerical study has been performed using finite element method for different types of soil profiles with different half-space impedances to assess how it affects the surface wave dispersion phenomenon. In addition to that, the effect of different data acquisition parameters on surface wave dispersion has also been studied.
{"title":"Surface Wave Dispersion in a Layered Medium for Varying Subsurface Scenarios","authors":"N. Roy, Aniket Desai, R. Jakka","doi":"10.4018/ijgee.2020070102","DOIUrl":"https://doi.org/10.4018/ijgee.2020070102","url":null,"abstract":"Surface wave techniques are widely used to characterize a site based on shear wave velocity (Vs) or stiffness variation with depth. It utilizes the dispersion property of Rayleigh wave in a heterogeneous media. Dispersion curve is obtained from analyzing collected field test data and the final Vs profile is extracted from the inversion of the generated dispersion curve. The varying subsoil structures influence whether one or more Rayleigh modes will participate in the resulting wave propagation phenomenon. So, neglecting the higher mode participation may sometimes results in a completely different velocity profile than the actual existing one. In this paper, a detailed and comprehensive numerical study has been performed using finite element method for different types of soil profiles with different half-space impedances to assess how it affects the surface wave dispersion phenomenon. In addition to that, the effect of different data acquisition parameters on surface wave dispersion has also been studied.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85170349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil site investigations such as boring logs, basic soil properties, spectral analysis of surface wave, and the examinations of geologic and geomorphologic were performed in Mae Lao area to investigate the susceptibility of liquefaction after the 6.2 Mw Chiang Rai Earthquake 2014. The study area was found to lay on a complex geological formation and geotechnical behavior with a condition of the high groundwater table. Being located on a high seismicity area (intensity V-VII Mercalli) governs the study area as a concern for high liquefaction hazards. Liquefaction susceptibility-based compositional criteria, soil resistance, and geologic criteria have been established, and consequently, the character of liquefaction potential is defined.
{"title":"Liquefaction Susceptibility Assessment Using Geotechnical and Geological Manners of Northern Thailand","authors":"Yayat Kusumahadi, Suttisak Soralump, Montri Jinagoolwipat","doi":"10.4018/ijgee.2020070103","DOIUrl":"https://doi.org/10.4018/ijgee.2020070103","url":null,"abstract":"Soil site investigations such as boring logs, basic soil properties, spectral analysis of surface wave, and the examinations of geologic and geomorphologic were performed in Mae Lao area to investigate the susceptibility of liquefaction after the 6.2 Mw Chiang Rai Earthquake 2014. The study area was found to lay on a complex geological formation and geotechnical behavior with a condition of the high groundwater table. Being located on a high seismicity area (intensity V-VII Mercalli) governs the study area as a concern for high liquefaction hazards. Liquefaction susceptibility-based compositional criteria, soil resistance, and geologic criteria have been established, and consequently, the character of liquefaction potential is defined.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88829390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.4018/ijgee.2020010104
M. Reddy, Rajashekara Reddy Konda, G. K. Kumar, Asadi S.S.
After the bifurcation of Telangana from Andhra Pradesh (AP) state in 2014, the Amaravati and adjoining localities has been proposed as a new capital region to the state of AP, India. As per the seismic zonation map of India, the proposed region falls in zone III. However, the prediction of damage level due to earthquakes is highly impossible, as it is influenced by many regional factors. In order to estimate the damage level from the future earthquakes in the present study, the various compositions involved in the regional fields of geological, geomorphological and soil characteristics are evaluated for the selected study region. In addition to this, to understand the seismicity of this region the earthquake catalogue and seismotectonic map have been prepared by collecting the data within 300km radial distance from Velgapudi (16° 52'N, 80° 51'E) as a center. The results of different fields represented in the form of thematic maps for this geographical information system (GIS) software has been used.
{"title":"Site Characterization and Evaluation of Seismic Sources for Amaravati Region","authors":"M. Reddy, Rajashekara Reddy Konda, G. K. Kumar, Asadi S.S.","doi":"10.4018/ijgee.2020010104","DOIUrl":"https://doi.org/10.4018/ijgee.2020010104","url":null,"abstract":"After the bifurcation of Telangana from Andhra Pradesh (AP) state in 2014, the Amaravati and adjoining localities has been proposed as a new capital region to the state of AP, India. As per the seismic zonation map of India, the proposed region falls in zone III. However, the prediction of damage level due to earthquakes is highly impossible, as it is influenced by many regional factors. In order to estimate the damage level from the future earthquakes in the present study, the various compositions involved in the regional fields of geological, geomorphological and soil characteristics are evaluated for the selected study region. In addition to this, to understand the seismicity of this region the earthquake catalogue and seismotectonic map have been prepared by collecting the data within 300km radial distance from Velgapudi (16° 52'N, 80° 51'E) as a center. The results of different fields represented in the form of thematic maps for this geographical information system (GIS) software has been used.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4018/ijgee.2020010104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72439685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.4018/ijgee.2020010101
Soumyadeep Sengupta, S. Kolathayar
This study presents an evaluation of liquefaction potential for combined cycle power plant site located in the Chittagong district, Bangladesh, using standard penetration test blow counts (SPT-N values). The peak ground acceleration (PGA) values at a bedrock level were estimated deterministically using both linear and point source models as well as different ground motion prediction equations (GMPEs). The surface level hazard was estimated using amplification factors for the soil conditions present and the response spectrum at the center of the plant site was plotted. The liquefaction potential for the site was arrived at by using the SPT-N values of 33 boreholes in the site and at every 3-meter interval from the ground level to a depth of 30 meters. The results from the LPI contours at successive depths indicate that in the majority of the borehole locations, the soil up to 15 meters depth had a significant hazard of liquefaction. These findings from the present study can prove to be crucial from the structural point of view, for any future construction activities in the area.
{"title":"Evaluation of Liquefaction Potential of Soil at a Power Plant Site in Chittagong, Bangladesh","authors":"Soumyadeep Sengupta, S. Kolathayar","doi":"10.4018/ijgee.2020010101","DOIUrl":"https://doi.org/10.4018/ijgee.2020010101","url":null,"abstract":"This study presents an evaluation of liquefaction potential for combined cycle power plant site located in the Chittagong district, Bangladesh, using standard penetration test blow counts (SPT-N values). The peak ground acceleration (PGA) values at a bedrock level were estimated deterministically using both linear and point source models as well as different ground motion prediction equations (GMPEs). The surface level hazard was estimated using amplification factors for the soil conditions present and the response spectrum at the center of the plant site was plotted. The liquefaction potential for the site was arrived at by using the SPT-N values of 33 boreholes in the site and at every 3-meter interval from the ground level to a depth of 30 meters. The results from the LPI contours at successive depths indicate that in the majority of the borehole locations, the soil up to 15 meters depth had a significant hazard of liquefaction. These findings from the present study can prove to be crucial from the structural point of view, for any future construction activities in the area.","PeriodicalId":42473,"journal":{"name":"International Journal of Geotechnical Earthquake Engineering","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82464980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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