Pub Date : 2022-10-21DOI: 10.1080/19386362.2022.2135226
Abolfazl Baghbani, Susanga Costa, B. O’Kelly, A. Soltani, M. Barzegar
ABSTRACT This study investigated the cyclic behaviour of a severe dilative silica sand from Rudsar, Northern Iran, through simple shear tests. For this purpose, monotonic (constant volume/vertical stress) and cyclic (constant vertical stress) tests were performed on moist sand specimens prepared at initial relative densities of 20–60%, vertical stresses of 100–300 kPa, and cyclic stress ratios of CSR = 0.20, 0.25 and 0.30. These also included bender element tests to determine the small-strain shear modulus G max. An increase in initial relative density, vertical stress and number of loading cycles led to a nonlinear increase in the secant shear modulus G sec, while the opposite was observed for increasing CSR. Moreover, increasing CSR improved the damping ratio, whereas increasing the initial relative density, vertical stress and/or number of loading cycles had negative effects on the damping ratio. Finally, the bender element test results showed that G max increased for increasing vertical stress and initial relative density.
{"title":"Experimental study on cyclic simple shear behaviour of predominantly dilative silica sand","authors":"Abolfazl Baghbani, Susanga Costa, B. O’Kelly, A. Soltani, M. Barzegar","doi":"10.1080/19386362.2022.2135226","DOIUrl":"https://doi.org/10.1080/19386362.2022.2135226","url":null,"abstract":"ABSTRACT This study investigated the cyclic behaviour of a severe dilative silica sand from Rudsar, Northern Iran, through simple shear tests. For this purpose, monotonic (constant volume/vertical stress) and cyclic (constant vertical stress) tests were performed on moist sand specimens prepared at initial relative densities of 20–60%, vertical stresses of 100–300 kPa, and cyclic stress ratios of CSR = 0.20, 0.25 and 0.30. These also included bender element tests to determine the small-strain shear modulus G max. An increase in initial relative density, vertical stress and number of loading cycles led to a nonlinear increase in the secant shear modulus G sec, while the opposite was observed for increasing CSR. Moreover, increasing CSR improved the damping ratio, whereas increasing the initial relative density, vertical stress and/or number of loading cycles had negative effects on the damping ratio. Finally, the bender element test results showed that G max increased for increasing vertical stress and initial relative density.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"17 1","pages":"91 - 105"},"PeriodicalIF":1.9,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47797859","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 : 2022-10-19DOI: 10.1080/19386362.2022.2131256
D. Sarkar, Frederik Koch, M. Goudarzy, T. Wichtmann
ABSTRACT The paper describes the effect of the various ends restraints on the cyclic liquefaction potential of Karlsruhe fine sand and examines the influence of grain shape and gradation on the cyclic liquefaction susceptibility of granular materials. To assess the influence of grain shape and gradation, three materials with same mean size but two different gradations were considered. Different scenarios were considered including the influence of differing sizes of the porous discs at end platens, influence of sample size ratio at similar diameter and varying membrane thickness. Additionally, the influence of using end lubrication or filter papers is investigated. The results reflect a pronounced effect of the liquefaction resistance of KFS using porous discs with a larger diameter, where a significant increase in the number of cycles to initial liquefaction was noted. Furthermore, initial liquefaction resistance for angular/sub-angular materials reduced with increasing gradation. In contrast, it remained relatively unchanged for round materials.
{"title":"The influence of various end restraints and grain shape on the cyclic undrained behaviour of granular materials","authors":"D. Sarkar, Frederik Koch, M. Goudarzy, T. Wichtmann","doi":"10.1080/19386362.2022.2131256","DOIUrl":"https://doi.org/10.1080/19386362.2022.2131256","url":null,"abstract":"ABSTRACT The paper describes the effect of the various ends restraints on the cyclic liquefaction potential of Karlsruhe fine sand and examines the influence of grain shape and gradation on the cyclic liquefaction susceptibility of granular materials. To assess the influence of grain shape and gradation, three materials with same mean size but two different gradations were considered. Different scenarios were considered including the influence of differing sizes of the porous discs at end platens, influence of sample size ratio at similar diameter and varying membrane thickness. Additionally, the influence of using end lubrication or filter papers is investigated. The results reflect a pronounced effect of the liquefaction resistance of KFS using porous discs with a larger diameter, where a significant increase in the number of cycles to initial liquefaction was noted. Furthermore, initial liquefaction resistance for angular/sub-angular materials reduced with increasing gradation. In contrast, it remained relatively unchanged for round materials.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"17 1","pages":"74 - 90"},"PeriodicalIF":1.9,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49648579","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 : 2022-09-08DOI: 10.1080/19386362.2022.2117350
Heitor Cardoso Bernardes, Aleones José da Cruz, Daniel Carmo Dias, Renato Pinto da Cunha, Juan Félix Rodríguez Rebolledo
ABSTRACT This technical note presents the results of two static load tests performed in a root micropile installed in a tropical lateritic soil profile. The tests were executed 6 years apart in order to investigate for signs of ageing effects in the pile side shear resistance and load settlement behaviour. Despite the measurements indicated an increase in the side shear capacity of the first soil layer, the results did not show clear signs of ageing effects, which occurrence was analysed considering different mechanisms. Soil suction possibly contributes to the differences between the tests, which should be carefully monitored for future studies of ageing effects in piles installed in unsaturated tropical sites.
{"title":"Comparison between load tests performed in a root micropile executed six years apart","authors":"Heitor Cardoso Bernardes, Aleones José da Cruz, Daniel Carmo Dias, Renato Pinto da Cunha, Juan Félix Rodríguez Rebolledo","doi":"10.1080/19386362.2022.2117350","DOIUrl":"https://doi.org/10.1080/19386362.2022.2117350","url":null,"abstract":"ABSTRACT This technical note presents the results of two static load tests performed in a root micropile installed in a tropical lateritic soil profile. The tests were executed 6 years apart in order to investigate for signs of ageing effects in the pile side shear resistance and load settlement behaviour. Despite the measurements indicated an increase in the side shear capacity of the first soil layer, the results did not show clear signs of ageing effects, which occurrence was analysed considering different mechanisms. Soil suction possibly contributes to the differences between the tests, which should be carefully monitored for future studies of ageing effects in piles installed in unsaturated tropical sites.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"16 1","pages":"1268 - 1275"},"PeriodicalIF":1.9,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45368533","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 : 2022-09-04DOI: 10.1080/19386362.2022.2117342
Aswathy M S, V. M
ABSTRACT An extensive geotechnical assessment of a hospital building under-crossed by twin tunnels is presented in this paper. The case study considered in the study is Phase III of Delhi Metro Gray line, which has been built recently using Tunnel Boring Machine. Finite element analysis was carried out to simulate the construction of two tunnels underneath the building, and the soil is simulated using an advanced constitutive model. The numerical model was validated against the field monitoring data, and the effect of tunnelling on the building deformation is also studied. Also, the comparison of building settlements with greenfield conditions is carried out. The study showed that the building influences the pattern of the settlement trough. Quantitative study of the settlement showed that there was no undue distress to the building due to the construction of twin tunnels, suggesting the safe crossing of twin tunnel below hospital building.
{"title":"Twin tunnelling caused distortions and its effect on a hospital building on mixed ground conditions","authors":"Aswathy M S, V. M","doi":"10.1080/19386362.2022.2117342","DOIUrl":"https://doi.org/10.1080/19386362.2022.2117342","url":null,"abstract":"ABSTRACT An extensive geotechnical assessment of a hospital building under-crossed by twin tunnels is presented in this paper. The case study considered in the study is Phase III of Delhi Metro Gray line, which has been built recently using Tunnel Boring Machine. Finite element analysis was carried out to simulate the construction of two tunnels underneath the building, and the soil is simulated using an advanced constitutive model. The numerical model was validated against the field monitoring data, and the effect of tunnelling on the building deformation is also studied. Also, the comparison of building settlements with greenfield conditions is carried out. The study showed that the building influences the pattern of the settlement trough. Quantitative study of the settlement showed that there was no undue distress to the building due to the construction of twin tunnels, suggesting the safe crossing of twin tunnel below hospital building.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"17 1","pages":"10 - 25"},"PeriodicalIF":1.9,"publicationDate":"2022-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44070115","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 : 2022-08-26DOI: 10.1080/19386362.2022.2114666
M. Bajestani, W. Oh
ABSTRACT Geotechnical projects are typically initiated with an unsupported vertical trench (UVT) in unsaturated soils. In this case, it is fundamental to consider the contribution of soil suction toward the shear strength and hydraulic conductivity of soils when analyzing the stability of UVTs. The soil–water characteristic curve (SWCC) is a vital tool for estimating the variations of shear strength and hydraulic conductivity of soils with soil suction. In this study, numerical analyses were conducted to investigate the influence of SWCC on the safe height and stand-up time of UVTs in sandy and glacial till materials. SWCCs were established using three SWCC fitting models based on experimental data. The analysis results demonstrate that it is essential to understand the critical differences between the SWCCs obtained using different fitting models and their influence on the safe height and stand-up time of UVTs, rather than simply comparing the estimates.
{"title":"Influence of soil-water characteristic curve on the safe height and stand-up time of unsupported vertical trenches in unsaturated soils","authors":"M. Bajestani, W. Oh","doi":"10.1080/19386362.2022.2114666","DOIUrl":"https://doi.org/10.1080/19386362.2022.2114666","url":null,"abstract":"ABSTRACT Geotechnical projects are typically initiated with an unsupported vertical trench (UVT) in unsaturated soils. In this case, it is fundamental to consider the contribution of soil suction toward the shear strength and hydraulic conductivity of soils when analyzing the stability of UVTs. The soil–water characteristic curve (SWCC) is a vital tool for estimating the variations of shear strength and hydraulic conductivity of soils with soil suction. In this study, numerical analyses were conducted to investigate the influence of SWCC on the safe height and stand-up time of UVTs in sandy and glacial till materials. SWCCs were established using three SWCC fitting models based on experimental data. The analysis results demonstrate that it is essential to understand the critical differences between the SWCCs obtained using different fitting models and their influence on the safe height and stand-up time of UVTs, rather than simply comparing the estimates.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"16 1","pages":"1179 - 1190"},"PeriodicalIF":1.9,"publicationDate":"2022-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46046141","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 : 2022-08-21DOI: 10.1080/19386362.2022.2106678
A. Yousefi, E. Aliaghaei, A. Kalhor, H. Jahanian, M. Azadi
ABSTRACT The development of freeze and thaw cycles causes heaps of injury to geotechnical structures, particularly roads, every year. In the present study, the effect of adding nanocement to improve the dynamic behaviour of clay under freeze-thaw cycles has been investigated. For this purpose, nanocement was mixed with clay from 1% to 4% according to the dry weight of the soil. Cylindrical samples of natural soil and soil stabilized with nanocement were prepared and cured up to 28 days. Then, dynamic triaxial experiments were performed on unstabilized samples and stabilized ones with 1, 2, 3, and 4% nanocement. The result shows the addition of nanocement increased the shear modulus and decreased the damping ratio. The highest increase in shear modulus was observed in the sample containing 4% nanocement approximately three times compared pure samples. Also, the shear modulus is reduced due to F-T cycles.
{"title":"The effect of freeze and thaw cycles on the dynamic properties of fine-grained soil stabilized with nanocement","authors":"A. Yousefi, E. Aliaghaei, A. Kalhor, H. Jahanian, M. Azadi","doi":"10.1080/19386362.2022.2106678","DOIUrl":"https://doi.org/10.1080/19386362.2022.2106678","url":null,"abstract":"ABSTRACT The development of freeze and thaw cycles causes heaps of injury to geotechnical structures, particularly roads, every year. In the present study, the effect of adding nanocement to improve the dynamic behaviour of clay under freeze-thaw cycles has been investigated. For this purpose, nanocement was mixed with clay from 1% to 4% according to the dry weight of the soil. Cylindrical samples of natural soil and soil stabilized with nanocement were prepared and cured up to 28 days. Then, dynamic triaxial experiments were performed on unstabilized samples and stabilized ones with 1, 2, 3, and 4% nanocement. The result shows the addition of nanocement increased the shear modulus and decreased the damping ratio. The highest increase in shear modulus was observed in the sample containing 4% nanocement approximately three times compared pure samples. Also, the shear modulus is reduced due to F-T cycles.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"16 1","pages":"1221 - 1233"},"PeriodicalIF":1.9,"publicationDate":"2022-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43700264","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 : 2022-07-13DOI: 10.1080/19386362.2022.2089443
Vinod Kumar Adigopula, Chandra Bogi Reddy, A. Garg, R. Kumar, G. Ramana
ABSTRACT An experimental laboratory program was conducted to understand the feasibility of steel slag and lime in the subgrade layer. The test was conducted on natural clay soil, lime, lime + steel slag stabilized cohesive subgrade soil. The lime portions were 2%, 4% and 6%, respectively. Similarly, steel slag was added to 20%, 25% and 30%, respectively, by the mass of dry soil. The strength of lime soil and lime + steel slag + soil increases with increasing curing period. The 7-day unconfined compressive strength (UCS) 2% lime soil and soil+20% steel slag + 2% lime is 3.20 MPa and 3.87 MPa, respectively. Eventually, this study supports the use of steel slag and lime in the construction of subgrade stabilization. Therefore, it is found that a lightweight deflectometer can be used as a quick strength evaluating tool on modified subgrade soil in the laboratory.
{"title":"Laboratory investigation of modified subgrade clay soil mix with steel slag and lime using static and dynamic test approach","authors":"Vinod Kumar Adigopula, Chandra Bogi Reddy, A. Garg, R. Kumar, G. Ramana","doi":"10.1080/19386362.2022.2089443","DOIUrl":"https://doi.org/10.1080/19386362.2022.2089443","url":null,"abstract":"ABSTRACT An experimental laboratory program was conducted to understand the feasibility of steel slag and lime in the subgrade layer. The test was conducted on natural clay soil, lime, lime + steel slag stabilized cohesive subgrade soil. The lime portions were 2%, 4% and 6%, respectively. Similarly, steel slag was added to 20%, 25% and 30%, respectively, by the mass of dry soil. The strength of lime soil and lime + steel slag + soil increases with increasing curing period. The 7-day unconfined compressive strength (UCS) 2% lime soil and soil+20% steel slag + 2% lime is 3.20 MPa and 3.87 MPa, respectively. Eventually, this study supports the use of steel slag and lime in the construction of subgrade stabilization. Therefore, it is found that a lightweight deflectometer can be used as a quick strength evaluating tool on modified subgrade soil in the laboratory.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"16 1","pages":"1211 - 1220"},"PeriodicalIF":1.9,"publicationDate":"2022-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49013261","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 : 2022-07-05DOI: 10.1080/19386362.2022.2096324
Mehdi Sedighi Moghadam, A. Zad, M. Yazdi, Matin Jalali Moghadam
ABSTRACT The dramatic increase in train speeds has made settlement control in the train bed a critical issue. High differential settlements on railway tracks, especially high-speed trains, can derail trains and cause irreparable financial and human losses. Deep Cement Mixing (DCM) piles are among the efficient methods to control the train path’s settlement, especially paths on soft clay soils . Recently, T-shaped cement soil mixing (TDM) piles became more popular than a single DCM pile. In this study, total and differential settlements along the path of a high-speed train on a loose bed reinforced with DCM and TDM piles were studied using PLAXIS 3D software. . Three different configuration patterns of the pile were investigated to determine the performance of DCM and TDM piles. Unlike the DCM piles, no differential settlements were captured in the TDM piles with a distance of 60, 120, and 180 cm between the piles.
{"title":"Performance of T-Shaped and conventional Cement-Soil deep mixing piles to stabilize soft base of High-Speed trains","authors":"Mehdi Sedighi Moghadam, A. Zad, M. Yazdi, Matin Jalali Moghadam","doi":"10.1080/19386362.2022.2096324","DOIUrl":"https://doi.org/10.1080/19386362.2022.2096324","url":null,"abstract":"ABSTRACT The dramatic increase in train speeds has made settlement control in the train bed a critical issue. High differential settlements on railway tracks, especially high-speed trains, can derail trains and cause irreparable financial and human losses. Deep Cement Mixing (DCM) piles are among the efficient methods to control the train path’s settlement, especially paths on soft clay soils . Recently, T-shaped cement soil mixing (TDM) piles became more popular than a single DCM pile. In this study, total and differential settlements along the path of a high-speed train on a loose bed reinforced with DCM and TDM piles were studied using PLAXIS 3D software. . Three different configuration patterns of the pile were investigated to determine the performance of DCM and TDM piles. Unlike the DCM piles, no differential settlements were captured in the TDM piles with a distance of 60, 120, and 180 cm between the piles.","PeriodicalId":47238,"journal":{"name":"International Journal of Geotechnical Engineering","volume":"16 1","pages":"1253 - 1267"},"PeriodicalIF":1.9,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41566125","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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