Pub Date : 2021-08-17DOI: 10.1080/17486025.2021.1955159
Shaoyi Li
ABSTRACT The dynamic responses of an unsaturated ground with or without an embankment are analysed using 2.5D finite element method (FEM) to investigate the effects of the soil saturation and the embankment. The Galerkin method is utilised to establish the weak form governing equations for an unsaturated poroviscoelastic medium in the framework of 2.5D FEM. To reduce the reflected waves from the truncated boundaries of the 2.5D FE model, the formulations of the perfectly match layer (PML) technique are coupled with the governing equations of the unsaturated medium. The unsaturated ground vibrations with an embankment under moving loads are analysed by the proposed 2.5D FE approach, to investigate the influences of an embankment on unsaturated ground vibrations. The results of this research found that the PML technique can effectively reduce the reflected waves in the 2.5D FE model of unsaturated grounds. The increased soil saturation would increase the ground vibration amplitude, as well as the pore water pressure. Constructing embankment on the unsaturated ground could reduce the vibrations amplitude under the moving load, however increase the ground vibrations at the foot of the embankment.
{"title":"Dynamic responses of unsaturated ground with or without embankment under moving loads using 2.5D FEM with perfectly match layer","authors":"Shaoyi Li","doi":"10.1080/17486025.2021.1955159","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955159","url":null,"abstract":"ABSTRACT The dynamic responses of an unsaturated ground with or without an embankment are analysed using 2.5D finite element method (FEM) to investigate the effects of the soil saturation and the embankment. The Galerkin method is utilised to establish the weak form governing equations for an unsaturated poroviscoelastic medium in the framework of 2.5D FEM. To reduce the reflected waves from the truncated boundaries of the 2.5D FE model, the formulations of the perfectly match layer (PML) technique are coupled with the governing equations of the unsaturated medium. The unsaturated ground vibrations with an embankment under moving loads are analysed by the proposed 2.5D FE approach, to investigate the influences of an embankment on unsaturated ground vibrations. The results of this research found that the PML technique can effectively reduce the reflected waves in the 2.5D FE model of unsaturated grounds. The increased soil saturation would increase the ground vibration amplitude, as well as the pore water pressure. Constructing embankment on the unsaturated ground could reduce the vibrations amplitude under the moving load, however increase the ground vibrations at the foot of the embankment.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1594 - 1617"},"PeriodicalIF":1.3,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49202399","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 : 2021-08-10DOI: 10.1080/17486025.2021.1955157
Djillali Amar Bouzid
ABSTRACT The assessment of slope stability factor by a FE analysis using the shear strength reduction method (SRM) enjoys several advantages and owns many shortcomings. As an alternative, a new FE approach called stress deviator increasing method (SDIM) is proposed. By means of a factor termed Mohr’s circle expansion factor, the new approach assesses the slope stability by incrementally increasing the mobilised principal stress deviator until the soil failure is reached. The numerical procedure is based then on a rigorous formulation as it preserves the definition of the safety factor consistent with that of LEM and maintains the progressive development of the shear stress on same plane on which the shear strength will occur at failure. The proposed method deals with the actual material by using the real strength parameters and rather than those reduced by a factor. The results of SDIM encoded in a computer code called were thoroughly assessed against those of both SRM and LEM using several slope examples involving and purely cohesive soils. Results of comparison encompassing factor of safety along with plastic strain distributions showed the reliability and the strength of the present method.
{"title":"Finite element analysis of a slope stability by incrementally increasing the mobilised principal stress deviator","authors":"Djillali Amar Bouzid","doi":"10.1080/17486025.2021.1955157","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955157","url":null,"abstract":"ABSTRACT The assessment of slope stability factor by a FE analysis using the shear strength reduction method (SRM) enjoys several advantages and owns many shortcomings. As an alternative, a new FE approach called stress deviator increasing method (SDIM) is proposed. By means of a factor termed Mohr’s circle expansion factor, the new approach assesses the slope stability by incrementally increasing the mobilised principal stress deviator until the soil failure is reached. The numerical procedure is based then on a rigorous formulation as it preserves the definition of the safety factor consistent with that of LEM and maintains the progressive development of the shear stress on same plane on which the shear strength will occur at failure. The proposed method deals with the actual material by using the real strength parameters and rather than those reduced by a factor. The results of SDIM encoded in a computer code called were thoroughly assessed against those of both SRM and LEM using several slope examples involving and purely cohesive soils. Results of comparison encompassing factor of safety along with plastic strain distributions showed the reliability and the strength of the present method.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1554 - 1574"},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41493952","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 : 2021-08-09DOI: 10.1080/17486025.2021.1955153
H. Haidar, H. Hamze, Mohammad Ezzedine, A. Barada, J. Halwani, A. Mechaymech
ABSTRACT This paper presents the performance and benefits of tyre rubber as substitute aggregates in the construction of concrete dams. The use of tyre rubber aims at minimising the quantities of traditional aggregate materials, and contributes in mitigating the solid waste problem in Lebanon. Full scale experiments and analyses were performed using data of Janna Dam (Lebanon). A first set of simulations related to structural and seismic analysis were carried out for concrete dams using traditional aggregate mixture to define a reference dam design scenario. A second set of simulations were proposed using tyre rubber aggregates to define a second scenario for the construction of the concrete dam. A comparison between the two scenarios shows that the introduction of tyre rubber as aggregates in the concrete mixture for the construction of the dam showed its performance and provides benefits in terms of reduction of traditional aggregates volume and of random disposal of tyre in the nature.
{"title":"Performance and benefits of tire rubber as substitute aggregates in the construction of concrete dams","authors":"H. Haidar, H. Hamze, Mohammad Ezzedine, A. Barada, J. Halwani, A. Mechaymech","doi":"10.1080/17486025.2021.1955153","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955153","url":null,"abstract":"ABSTRACT This paper presents the performance and benefits of tyre rubber as substitute aggregates in the construction of concrete dams. The use of tyre rubber aims at minimising the quantities of traditional aggregate materials, and contributes in mitigating the solid waste problem in Lebanon. Full scale experiments and analyses were performed using data of Janna Dam (Lebanon). A first set of simulations related to structural and seismic analysis were carried out for concrete dams using traditional aggregate mixture to define a reference dam design scenario. A second set of simulations were proposed using tyre rubber aggregates to define a second scenario for the construction of the concrete dam. A comparison between the two scenarios shows that the introduction of tyre rubber as aggregates in the concrete mixture for the construction of the dam showed its performance and provides benefits in terms of reduction of traditional aggregates volume and of random disposal of tyre in the nature.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1485 - 1498"},"PeriodicalIF":1.3,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42565730","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}
ABSTRACT The loss in strength of engineered geo-materials due to their exposure to adverse environmental conditions is a major problem and is investigated in terms of durability. In the present study, geo-materials are developed using the sand obtained from river Yamuna and is stabilised with bentonite or two different types of biopolymer (Guar gum and Xanthan gum) separately. The maximum percentage of bentonite is fixed as 25% by dry weight, whereas the biopolymer (0.5%, 1.0%, 1.5%, and 2.0%) is used by making its solution with distilled water. A continuous increase in the unconfined compressive strength is observed in the bentonite stabilised sand whereas an optimum percentage of both the biopolymers is observed as 1.5%. The penetration resistance is presented in term of CBR value and resilient modulus is calculated using the same. Although, the bentonite and Guar gum stabilised sand demonstrate higher strength compared to Xanthan gum stabilised sand; however, the former is not found stable when submerged in water. More than 50% loss in strength for sand stabilised with 1.5% and 2.0% Xanthan gum is observed. Further, the stability of the biopolymer stabilised sand in submerged condition is discussed with the help of SEM images.
{"title":"A comparative study between strength and durability of bentonite and natural gum stabilised sand","authors":"S. Alam, Assefa Weldu Gebremedhin, Hika Wachila Atomsa, Afzal Husain Khan","doi":"10.1080/17486025.2021.1961026","DOIUrl":"https://doi.org/10.1080/17486025.2021.1961026","url":null,"abstract":"ABSTRACT The loss in strength of engineered geo-materials due to their exposure to adverse environmental conditions is a major problem and is investigated in terms of durability. In the present study, geo-materials are developed using the sand obtained from river Yamuna and is stabilised with bentonite or two different types of biopolymer (Guar gum and Xanthan gum) separately. The maximum percentage of bentonite is fixed as 25% by dry weight, whereas the biopolymer (0.5%, 1.0%, 1.5%, and 2.0%) is used by making its solution with distilled water. A continuous increase in the unconfined compressive strength is observed in the bentonite stabilised sand whereas an optimum percentage of both the biopolymers is observed as 1.5%. The penetration resistance is presented in term of CBR value and resilient modulus is calculated using the same. Although, the bentonite and Guar gum stabilised sand demonstrate higher strength compared to Xanthan gum stabilised sand; however, the former is not found stable when submerged in water. More than 50% loss in strength for sand stabilised with 1.5% and 2.0% Xanthan gum is observed. Further, the stability of the biopolymer stabilised sand in submerged condition is discussed with the help of SEM images.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1722 - 1734"},"PeriodicalIF":1.3,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46214627","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 : 2021-08-03DOI: 10.1080/17486025.2021.1961025
Hongchao Zhao, Ting-Ting Ren, A. Remennikov
ABSTRACT This paper presents a series of novel hybrid columns incorporating emerging materials, being the alternative to pumpable standing supports used in underground mines. The infill material of these hybrid columns is the cementitious grout material while the exterior containers are either made of polyvinyl chloride (PVC), fibre-reinforced polymer (FRP) composite, geogrid or the combination of each two materials. To investigate the mechanical response of these columns under the uniaxial compression loading, the systematic laboratory tests covering eight large-scale tubular columns were conducted and the test results showed that: (1) the strain constant behaviour of PVC-confined cementitious grout (PCC) column is mainly attributed to the relatively low confinement after the yielding of the PVC tube; (2) the high strength-to-weight ratio and linear tensile behaviour of FRP leads to the stress-hardening behaviour of FRP-confined cementitious grout (FCC) column and the enhanced compressive behaviour of FCC is mainly related to FRP thickness; (3) both the FRP-PVC confined cementitious grout (FPCC) columns and FRP-geogrid confined cementitious grout (FGCC) columns exhibited the superior compressive behaviour either in terms of the large axial deformation or the load carrying capacity, compared with the unconfined cementitious grout material (UCM) under uniaxial compression loading.
{"title":"Hybrid roof standing supports in underground mining: concept and behaviour","authors":"Hongchao Zhao, Ting-Ting Ren, A. Remennikov","doi":"10.1080/17486025.2021.1961025","DOIUrl":"https://doi.org/10.1080/17486025.2021.1961025","url":null,"abstract":"ABSTRACT This paper presents a series of novel hybrid columns incorporating emerging materials, being the alternative to pumpable standing supports used in underground mines. The infill material of these hybrid columns is the cementitious grout material while the exterior containers are either made of polyvinyl chloride (PVC), fibre-reinforced polymer (FRP) composite, geogrid or the combination of each two materials. To investigate the mechanical response of these columns under the uniaxial compression loading, the systematic laboratory tests covering eight large-scale tubular columns were conducted and the test results showed that: (1) the strain constant behaviour of PVC-confined cementitious grout (PCC) column is mainly attributed to the relatively low confinement after the yielding of the PVC tube; (2) the high strength-to-weight ratio and linear tensile behaviour of FRP leads to the stress-hardening behaviour of FRP-confined cementitious grout (FCC) column and the enhanced compressive behaviour of FCC is mainly related to FRP thickness; (3) both the FRP-PVC confined cementitious grout (FPCC) columns and FRP-geogrid confined cementitious grout (FGCC) columns exhibited the superior compressive behaviour either in terms of the large axial deformation or the load carrying capacity, compared with the unconfined cementitious grout material (UCM) under uniaxial compression loading.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1707 - 1721"},"PeriodicalIF":1.3,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46389509","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 : 2021-08-03DOI: 10.1080/17486025.2021.1955163
R. Ganesh, J. Sahoo, S. Rajesh
ABSTRACT This paper presents a unified semi-analytical solution to investigate the passive earth resistance of unsaturated soils retained by a rigid wall in the framework of limit-equilibrium approach based on a rotational log-spiral failure mechanism. Coupled influences of unit weight and suction stress changes in unsaturated soils under different steady vertical flow conditions have been considered to provide a more realistic solution. The impact of different parameters such as effective internal friction angle soil, inclination of backfill surface and wall back face, surcharge pressure, height of wall, location of water table, and soil–wall interface friction has been explored by performing a parametric study. It has been found that the changes in the suction stress and unit weight of unsaturated soils under different input parameters have a greater effect on modifying the critical slip surface, and magnitude and point of application of passive earth resistance on the retaining walls. The results obtained from the present study compare reasonably well with the solutions in the literature.
{"title":"Passive resistance of unsaturated backfill under steady state flow conditions","authors":"R. Ganesh, J. Sahoo, S. Rajesh","doi":"10.1080/17486025.2021.1955163","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955163","url":null,"abstract":"ABSTRACT This paper presents a unified semi-analytical solution to investigate the passive earth resistance of unsaturated soils retained by a rigid wall in the framework of limit-equilibrium approach based on a rotational log-spiral failure mechanism. Coupled influences of unit weight and suction stress changes in unsaturated soils under different steady vertical flow conditions have been considered to provide a more realistic solution. The impact of different parameters such as effective internal friction angle soil, inclination of backfill surface and wall back face, surcharge pressure, height of wall, location of water table, and soil–wall interface friction has been explored by performing a parametric study. It has been found that the changes in the suction stress and unit weight of unsaturated soils under different input parameters have a greater effect on modifying the critical slip surface, and magnitude and point of application of passive earth resistance on the retaining walls. The results obtained from the present study compare reasonably well with the solutions in the literature.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1653 - 1669"},"PeriodicalIF":1.3,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47816617","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 : 2021-08-02DOI: 10.1080/17486025.2021.1955162
Henrique de Andrade Penido, A. Funato, H. Metsugi, V. F. Navarro Torres, Juan Manuel Girao Sotomayor, Phillip Dight, Rodrigo Peluci de Figueiredo, André Pacheco de Assis, A. Guimarães
ABSTRACT This study presents an unprecedented campaign of measurements (magnitudes and orientations) of the in situ stresses in itabirite rocks of the Brazilian Iron Quadrangle region using the hydraulic fracturing (HF), deformation rate analysis (DRA) and diametrical core deformation analysis (DCDA) methods. The previous studies of this rock mass consider estimated values of k, and the practice of using in situ stress tests to support geotechnical analyses of the rock mass of this region has not been adopted. The study site is located at a depth of up to 400 m around a pit. The rock mass under study shows the presence of different geological structures, which made performing the tests difficult. The DRA results show a marked difference compared to the HF and DCDA results; the horizontal stresses were greater than the vertical stresses, which is a finding that may occur due to local geodynamic influences. The results contribute to the understanding of the strains and stresses induced by mining activities in the Brazilian Iron Quadrangle. For a better determination of the regional in situ stresses in the rock mass of the Brazilian Iron Quadrangle, new HF tests, as well as hydraulic testing of pre-existing fractures are recommended.
{"title":"Application of the HF, DRA and DCDA technologies for in situ stress determination in Iron Quadrangle rock masses","authors":"Henrique de Andrade Penido, A. Funato, H. Metsugi, V. F. Navarro Torres, Juan Manuel Girao Sotomayor, Phillip Dight, Rodrigo Peluci de Figueiredo, André Pacheco de Assis, A. Guimarães","doi":"10.1080/17486025.2021.1955162","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955162","url":null,"abstract":"ABSTRACT This study presents an unprecedented campaign of measurements (magnitudes and orientations) of the in situ stresses in itabirite rocks of the Brazilian Iron Quadrangle region using the hydraulic fracturing (HF), deformation rate analysis (DRA) and diametrical core deformation analysis (DCDA) methods. The previous studies of this rock mass consider estimated values of k, and the practice of using in situ stress tests to support geotechnical analyses of the rock mass of this region has not been adopted. The study site is located at a depth of up to 400 m around a pit. The rock mass under study shows the presence of different geological structures, which made performing the tests difficult. The DRA results show a marked difference compared to the HF and DCDA results; the horizontal stresses were greater than the vertical stresses, which is a finding that may occur due to local geodynamic influences. The results contribute to the understanding of the strains and stresses induced by mining activities in the Brazilian Iron Quadrangle. For a better determination of the regional in situ stresses in the rock mass of the Brazilian Iron Quadrangle, new HF tests, as well as hydraulic testing of pre-existing fractures are recommended.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1670 - 1694"},"PeriodicalIF":1.3,"publicationDate":"2021-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17486025.2021.1955162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43396507","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 : 2021-07-26DOI: 10.1080/17486025.2021.1955155
Endene Emmanuel, Lee Li Yong, Nicholas Fogne Appiah, S. Gawu
ABSTRACT The possibility of stabilising a residual soil using lime and polyethylene terephthalate (PET) fibre by employing the central composite design technique in response surface methodology and using the desirability function to identify optimum additive combinations for the improvement in the strength properties of the treated soil was explored in this study. The effects of the independent variables (lime content, PET content, and curing duration) on the responses [unconfined compressive strength (UCS) and flexural strength (FS)] were investigated by analysis of variance (ANOVA). The results indicate that the developed mathematical models are statistically significant (p ≤ 0.05) through the analysis of variance, thus they are applicable for the optimisation process. Predicted values from the developed models were found to be in good agreement with their experimental counterparts. The optimum conditions were found to be 9% lime content, 1.9% PET fibre content, and 30 days curing duration, with a designated maximum desirability function (D = 0.996). Microstructural investigations revealed that the formation of calcium-aluminate-hydrate and calcium-silicate-hydrate were the key components liable for the improvement in the strength properties of the treated soil. The reported findings engaged the concurrent application of lime and PET fibre to improve the strength properties of residual soils.
{"title":"Response surface methodology: a tool to optimise the contents of lime and polyethylene terephthalate (PET) fiber for stabilising a residual soil","authors":"Endene Emmanuel, Lee Li Yong, Nicholas Fogne Appiah, S. Gawu","doi":"10.1080/17486025.2021.1955155","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955155","url":null,"abstract":"ABSTRACT The possibility of stabilising a residual soil using lime and polyethylene terephthalate (PET) fibre by employing the central composite design technique in response surface methodology and using the desirability function to identify optimum additive combinations for the improvement in the strength properties of the treated soil was explored in this study. The effects of the independent variables (lime content, PET content, and curing duration) on the responses [unconfined compressive strength (UCS) and flexural strength (FS)] were investigated by analysis of variance (ANOVA). The results indicate that the developed mathematical models are statistically significant (p ≤ 0.05) through the analysis of variance, thus they are applicable for the optimisation process. Predicted values from the developed models were found to be in good agreement with their experimental counterparts. The optimum conditions were found to be 9% lime content, 1.9% PET fibre content, and 30 days curing duration, with a designated maximum desirability function (D = 0.996). Microstructural investigations revealed that the formation of calcium-aluminate-hydrate and calcium-silicate-hydrate were the key components liable for the improvement in the strength properties of the treated soil. The reported findings engaged the concurrent application of lime and PET fibre to improve the strength properties of residual soils.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1516 - 1535"},"PeriodicalIF":1.3,"publicationDate":"2021-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17486025.2021.1955155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41932335","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 : 2021-07-21DOI: 10.1080/17486025.2021.1955158
Imad Alainachi, M. Fall
ABSTRACT Cemented paste backfill (CPB) has been extensively used in the mine industry to backfill underground mine cavities for ground support and/or tailings management. Once placed in mine underground cavities, the geotechnical and liquefaction response of the CPB under dynamic (cyclic) loadings is a key design concern in mine backfilling. Moreover, fresh CPB might be exposed to several sources of heat that might affect its cyclic behaviour and liquefaction potential. This manuscript presents findings of assessing the effect of backfill temperature on its geotechnical and liquefaction response to cyclic loading by using shaking table. CPB mixtures were prepared under different temperatures, poured into a flexible laminar shear box, cured (under the same mixing temperature) for 2.5 hours, and then exposed to cyclic loading using 1-D Shaking table. Obtained results illustrate that CPB prepared and cured under the temperature of 20°C can be prone to liquefaction under the studied loading conditions. However, CPB prepared and cured below a temperature of 35°C is resistant to liquefaction. These results provide better comprehension of the effect of backfill temperature on the cyclic behaviour of CPB, and thus assist in designing more efficient CPB structures.
{"title":"Temperature induced changes in the behaviour of cementing fine-grained soils under dynamic loadings","authors":"Imad Alainachi, M. Fall","doi":"10.1080/17486025.2021.1955158","DOIUrl":"https://doi.org/10.1080/17486025.2021.1955158","url":null,"abstract":"ABSTRACT Cemented paste backfill (CPB) has been extensively used in the mine industry to backfill underground mine cavities for ground support and/or tailings management. Once placed in mine underground cavities, the geotechnical and liquefaction response of the CPB under dynamic (cyclic) loadings is a key design concern in mine backfilling. Moreover, fresh CPB might be exposed to several sources of heat that might affect its cyclic behaviour and liquefaction potential. This manuscript presents findings of assessing the effect of backfill temperature on its geotechnical and liquefaction response to cyclic loading by using shaking table. CPB mixtures were prepared under different temperatures, poured into a flexible laminar shear box, cured (under the same mixing temperature) for 2.5 hours, and then exposed to cyclic loading using 1-D Shaking table. Obtained results illustrate that CPB prepared and cured under the temperature of 20°C can be prone to liquefaction under the studied loading conditions. However, CPB prepared and cured below a temperature of 35°C is resistant to liquefaction. These results provide better comprehension of the effect of backfill temperature on the cyclic behaviour of CPB, and thus assist in designing more efficient CPB structures.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1575 - 1593"},"PeriodicalIF":1.3,"publicationDate":"2021-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17486025.2021.1955158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44280259","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 : 2021-07-21DOI: 10.1080/17486025.2021.1955154
Ahmed Mohammed Hasan, S. Abdulhamid, H. Ibrahim
ABSTRACT The present research aims to explore experimentally the performance and modes of failure of the wetting-induced collapse of fully penetrating reinforced and unreinforced models of a short single sand column in a collapsible soil subjected to partial inundation through a series of model tests under high constant total stress of more than 200 kPa. A specific loading frame and a test container were designed to apply vertical pressure and measure vertical movements of the columns . The experimental test results demonstrated that providing only sand columns in collapsing soil have no significant contribution in reducing the large volume change and sudden collapse when wet. In contrast, geosynthetic-encased columns prevented the occurrence of wetting-induced collapse and highly reduced the sudden vertical movements to a gradual process under relatively high applied pressure. Additionally, a slight change in the dry density of the soil had a dramatic influence on the behaviour of the wetting-induced collapse and modes of failure. In this study, the experimental test results and theoretical results from different analytical approaches in the literature have confirmed that it is practically possible to apply high total stress of more than 300 kPa on a single footing on collapsible soils subjected to wetting condition.
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