Pub Date : 2021-12-27DOI: 10.1080/17486025.2021.2007301
Danny Useche-Infante, Gonzalo Aiassa Martínez, P. Arrua, M. Eberhardt
ABSTRACT Using plate load test to evaluate the scale effects of shallow foundation bearing capacity on geogrid-reinforced sand is expensive because large boxes need to be built, and the devices to apply the loads to the reinforced soil are complex. Consequently, the finite element method is an alternative to investigate this phenomenon. In this study, a series of 3D axi-symmetry finite element models were developed to study the scale effect on the bearing capacity of circular footings resting on geogrid-reinforced sand. First, a 100 mm-diameter circular foundation supported by geogrid-reinforced sand was simulated in order to validate the finite element model with laboratory tests. Subsequently, different models were made by increasing the diameter of the foundation and the diameter of the geogrid in the same proportion. Modelling results indicated that as the foundation diameter increased, the bearing capacity of unreinforced and reinforced soil decreased. Likewise, the benefit obtained from the reinforcement was less when the model size was increased.
{"title":"Scale effect on the behavior of circular footing on geogrid-reinforced sand using numerical analysis","authors":"Danny Useche-Infante, Gonzalo Aiassa Martínez, P. Arrua, M. Eberhardt","doi":"10.1080/17486025.2021.2007301","DOIUrl":"https://doi.org/10.1080/17486025.2021.2007301","url":null,"abstract":"ABSTRACT Using plate load test to evaluate the scale effects of shallow foundation bearing capacity on geogrid-reinforced sand is expensive because large boxes need to be built, and the devices to apply the loads to the reinforced soil are complex. Consequently, the finite element method is an alternative to investigate this phenomenon. In this study, a series of 3D axi-symmetry finite element models were developed to study the scale effect on the bearing capacity of circular footings resting on geogrid-reinforced sand. First, a 100 mm-diameter circular foundation supported by geogrid-reinforced sand was simulated in order to validate the finite element model with laboratory tests. Subsequently, different models were made by increasing the diameter of the foundation and the diameter of the geogrid in the same proportion. Modelling results indicated that as the foundation diameter increased, the bearing capacity of unreinforced and reinforced soil decreased. Likewise, the benefit obtained from the reinforcement was less when the model size was increased.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"34 - 47"},"PeriodicalIF":1.3,"publicationDate":"2021-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48908985","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 : 2021-12-24DOI: 10.1080/17486025.2021.2012077
B. Kumar, J. Sahoo
ABSTRACT In this paper, the required limiting pressure to be offered by the lining of circular tunnels formed in clay overlain by another clay layer under undrained condition has been computed. Both the layers are anisotropic in nature from the shear strength point of view. The upper layer is considered relatively either weaker or stronger than the lower layer i.e. undrained anisotropic shear strength of upper layer is relatively either smaller or greater than that of lower layer. Lower bound limit analysis coupled with finite element formulation and second order cone programming has been employed to perform the analysis. For different thickness of upper layer above crown of tunnel, the limiting lining pressure to maintain stability of tunnel has been obtained by varying thickness of lower clay layer, anisotropic parameters, normalised overburden pressure, undrained cohesion and unit weight of upper layer relative to lower layer. The solutions obtained from this analysis reveal that anisotropy in shear strength has significant effect on the required lining pressure to keep tunnel in stable condition.
{"title":"Lining pressure for circular tunnels in two layered clay with anisotropic undrained shear strength","authors":"B. Kumar, J. Sahoo","doi":"10.1080/17486025.2021.2012077","DOIUrl":"https://doi.org/10.1080/17486025.2021.2012077","url":null,"abstract":"ABSTRACT In this paper, the required limiting pressure to be offered by the lining of circular tunnels formed in clay overlain by another clay layer under undrained condition has been computed. Both the layers are anisotropic in nature from the shear strength point of view. The upper layer is considered relatively either weaker or stronger than the lower layer i.e. undrained anisotropic shear strength of upper layer is relatively either smaller or greater than that of lower layer. Lower bound limit analysis coupled with finite element formulation and second order cone programming has been employed to perform the analysis. For different thickness of upper layer above crown of tunnel, the limiting lining pressure to maintain stability of tunnel has been obtained by varying thickness of lower clay layer, anisotropic parameters, normalised overburden pressure, undrained cohesion and unit weight of upper layer relative to lower layer. The solutions obtained from this analysis reveal that anisotropy in shear strength has significant effect on the required lining pressure to keep tunnel in stable condition.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"91 - 104"},"PeriodicalIF":1.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60093278","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 : 2021-12-22DOI: 10.1080/17486025.2021.2014987
G. Spagnoli, S. Shimobe
ABSTRACT Atterberg limits of soils are the most basic and widely used geotechnical characterisation of fine-grained soils. While the indicative values for different clay types (e.g. kaolinite, smectite, illite) are quite known, no in-depth statistical analysis has been performed to understand any possible variations of the values. In this note, 128 data on Atterberg limits of kaolinitic clays have been gathered and statistically analysed to understand the distribution of the data and to understand whether variations in mean values and variances are detectable. A measurement system analysis has been performed on a kaolinitic sample to detect possible variations of measurements. Based on regression analysis to obtain plasticity index (PI) values from liquid limit (LL) values, a Monte Carlo analysis was performed by building models of possible results by substituting a range of values for the LL factors.
{"title":"Statistics of Atterberg limit values of some pure kaolinitic clays","authors":"G. Spagnoli, S. Shimobe","doi":"10.1080/17486025.2021.2014987","DOIUrl":"https://doi.org/10.1080/17486025.2021.2014987","url":null,"abstract":"ABSTRACT Atterberg limits of soils are the most basic and widely used geotechnical characterisation of fine-grained soils. While the indicative values for different clay types (e.g. kaolinite, smectite, illite) are quite known, no in-depth statistical analysis has been performed to understand any possible variations of the values. In this note, 128 data on Atterberg limits of kaolinitic clays have been gathered and statistically analysed to understand the distribution of the data and to understand whether variations in mean values and variances are detectable. A measurement system analysis has been performed on a kaolinitic sample to detect possible variations of measurements. Based on regression analysis to obtain plasticity index (PI) values from liquid limit (LL) values, a Monte Carlo analysis was performed by building models of possible results by substituting a range of values for the LL factors.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"105 - 120"},"PeriodicalIF":1.3,"publicationDate":"2021-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42337564","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 : 2021-12-22DOI: 10.1080/17486025.2021.2005159
Debabrata Giri, Anamika Bandopadhyay
ABSTRACT The knowledge of earth pressure concepts plays a major role to design a retaining wall. The most traditional pseudo-static methodology as proposed by Mononobe–Okabe gives the direct approximation of earth pressure in seismic condition. This paper utilised the pseudo-dynamic methodology to figure out the seismic earth pressure on rigid wall with cohesion less backfill along with considering the effects of time, phase difference, soil amplification factor along with the variation in seismic velocities. The main contribution is the soil amplification and backfill inclination which is not given much attention before. By considering the above factors coefficients the seismic earth pressure against retaining wall is determined. The coefficient of seismic passive earth pressure decreases with the increase of soil amplification keeping other properties as standard values. The value of coefficient of seismic active earth pressure increases with increase of soil amplification. The comparison is also done without taking backfill angle for both coefficients of seismic earth pressures. The influence of all the soil properties like backfill angle, wall friction angle, soil friction angle, non-dimensional parameters are shown in tabular format as well as in the graphical with respect to the soil amplification which is more realistic towards the design.
{"title":"Influence of soil amplification and backfill angle on seismic earth pressure coefficients by pseudo dynamic method","authors":"Debabrata Giri, Anamika Bandopadhyay","doi":"10.1080/17486025.2021.2005159","DOIUrl":"https://doi.org/10.1080/17486025.2021.2005159","url":null,"abstract":"ABSTRACT The knowledge of earth pressure concepts plays a major role to design a retaining wall. The most traditional pseudo-static methodology as proposed by Mononobe–Okabe gives the direct approximation of earth pressure in seismic condition. This paper utilised the pseudo-dynamic methodology to figure out the seismic earth pressure on rigid wall with cohesion less backfill along with considering the effects of time, phase difference, soil amplification factor along with the variation in seismic velocities. The main contribution is the soil amplification and backfill inclination which is not given much attention before. By considering the above factors coefficients the seismic earth pressure against retaining wall is determined. The coefficient of seismic passive earth pressure decreases with the increase of soil amplification keeping other properties as standard values. The value of coefficient of seismic active earth pressure increases with increase of soil amplification. The comparison is also done without taking backfill angle for both coefficients of seismic earth pressures. The influence of all the soil properties like backfill angle, wall friction angle, soil friction angle, non-dimensional parameters are shown in tabular format as well as in the graphical with respect to the soil amplification which is more realistic towards the design.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"2005 - 2012"},"PeriodicalIF":1.3,"publicationDate":"2021-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49579204","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 : 2021-12-21DOI: 10.1080/17486025.2021.2012075
V. F. Navarro Torres, C. Dinis da Gama, Juan Manuel Girao Sotomayor
ABSTRACT This work seeks to contribute to the understanding of the intrinsic, geological-geotechnical and operational causes of overbreak in tunnels through the case study of the overbreak of two tunnels during the construction phase of the Alqueva hydroelectric plant in Portugal. The excavations were carried out in lithologies with good geotechnical characteristics, for this reason, overbreak was not expected. To determine if the overbreak was done due to operational negligence, mathematical models were developed to quantify (1) the overbreak by the peripheral divergence involving the specific load of the explosives used in the peripheral zone of the tunnel, (2) the geotechnical quality of the rock mass, and (3) the operational aspects. For the mathematical modelling, it was necessary to characterise the causes of excavation damage zone (EDZ), considering the participation of the developer and the contractor. To analyse the calculations and determine the acceptable limits, the Swiss standard SIA 198, which recommends a maximum tolerable overbreak, was used.
{"title":"Post-work inspection for overbreak in tunnels: a case study application to the Alqueva hydroelectric plant","authors":"V. F. Navarro Torres, C. Dinis da Gama, Juan Manuel Girao Sotomayor","doi":"10.1080/17486025.2021.2012075","DOIUrl":"https://doi.org/10.1080/17486025.2021.2012075","url":null,"abstract":"ABSTRACT This work seeks to contribute to the understanding of the intrinsic, geological-geotechnical and operational causes of overbreak in tunnels through the case study of the overbreak of two tunnels during the construction phase of the Alqueva hydroelectric plant in Portugal. The excavations were carried out in lithologies with good geotechnical characteristics, for this reason, overbreak was not expected. To determine if the overbreak was done due to operational negligence, mathematical models were developed to quantify (1) the overbreak by the peripheral divergence involving the specific load of the explosives used in the peripheral zone of the tunnel, (2) the geotechnical quality of the rock mass, and (3) the operational aspects. For the mathematical modelling, it was necessary to characterise the causes of excavation damage zone (EDZ), considering the participation of the developer and the contractor. To analyse the calculations and determine the acceptable limits, the Swiss standard SIA 198, which recommends a maximum tolerable overbreak, was used.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"80 - 89"},"PeriodicalIF":1.3,"publicationDate":"2021-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44902380","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 : 2021-12-07DOI: 10.1080/17486025.2021.2006803
J. C. Egbueri
ABSTRACT Multiple machine learning algorithms were integrated in this study to assess the geotechnical peculiarities of tropical soils from erosion sites in Nigeria. Laboratory analyses of the soils, which followed standard methods, revealed that they are erodible in nature. Results of correlation, principal component and factor analyses revealed the relationships between geotechnical variables, which were later used for artificial neural network (ANN) modelling. Soil particle distribution was predicted and analyzed using ANN1 (with sigmoid output activation) and ANN2 (with identity output activation). However, ANN2 gave more reliable prediction than ANN1, with R2 averaging 0.913 and 0.522, respectively. Low ANN model errors were also reported. Furthermore, soil erodibility potential, with emphasis on the grainsize distribution, was predicted using logistic regression analysis (LRA). The LRA results showed that the model accurately classified soil erosion events by 90%, and further revealed that sand content is the priority influencer of soil erodibility, more than gravel and fines contents. Thus, the likelihood of high soil erosion events in the area increases with sand %. The logistic regression model was tested for reliability based on Cox & Snell and Nagelkerke R-squares – R2 = 0.593 and R2 = 0.791, respectively – indicating that the model is acceptable and reliable.
{"title":"Use of joint supervised machine learning algorithms in assessing the geotechnical peculiarities of erodible tropical soils from southeastern Nigeria","authors":"J. C. Egbueri","doi":"10.1080/17486025.2021.2006803","DOIUrl":"https://doi.org/10.1080/17486025.2021.2006803","url":null,"abstract":"ABSTRACT Multiple machine learning algorithms were integrated in this study to assess the geotechnical peculiarities of tropical soils from erosion sites in Nigeria. Laboratory analyses of the soils, which followed standard methods, revealed that they are erodible in nature. Results of correlation, principal component and factor analyses revealed the relationships between geotechnical variables, which were later used for artificial neural network (ANN) modelling. Soil particle distribution was predicted and analyzed using ANN1 (with sigmoid output activation) and ANN2 (with identity output activation). However, ANN2 gave more reliable prediction than ANN1, with R2 averaging 0.913 and 0.522, respectively. Low ANN model errors were also reported. Furthermore, soil erodibility potential, with emphasis on the grainsize distribution, was predicted using logistic regression analysis (LRA). The LRA results showed that the model accurately classified soil erosion events by 90%, and further revealed that sand content is the priority influencer of soil erodibility, more than gravel and fines contents. Thus, the likelihood of high soil erosion events in the area increases with sand %. The logistic regression model was tested for reliability based on Cox & Snell and Nagelkerke R-squares – R2 = 0.593 and R2 = 0.791, respectively – indicating that the model is acceptable and reliable.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"16 - 33"},"PeriodicalIF":1.3,"publicationDate":"2021-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45206637","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 : 2021-12-03DOI: 10.1080/17486025.2021.2006490
A. Worku, Beza Tesfu
ABSTRACT A variety of mechanical and continuum subgrade models ranging from the simplest Winkler model to the more complex ones were proposed in the past to address the problem of foundations on elastic subgrades. Most of them are based on simplifying assumptions. With the objective of arriving at a reliable few-parameter analytical model, two- and single-parameter mechanical equivalents of a rigorous continuum foundation model proposed by the first author are presented that are adjusted with respect to the finite-element (FE) software, PLAXIS. The performance of both variants of the model is tested on beams by comparing with other analytical models and with FE models for a range of variables. Both variants performed remarkably well, especially the two-parameter variant. The adjusted model parameters are provided for practical use. Adjustment factors are also established for the popular Vlasov’s model. Comparison between the proposed and FE models shows that Vlasov’s adjustment factor is sensitive and varies over a comparatively wide range, and the model even becomes unadjustable for short beams. In contrast, the proposed models consistently yield very good results for all ranges of beams with an adjustment factor that is less sensitive and varying within a narrow range confirming their good quality.
{"title":"A comparative study of a new subgrade model on beams with respect to FE and existing analytical models","authors":"A. Worku, Beza Tesfu","doi":"10.1080/17486025.2021.2006490","DOIUrl":"https://doi.org/10.1080/17486025.2021.2006490","url":null,"abstract":"ABSTRACT A variety of mechanical and continuum subgrade models ranging from the simplest Winkler model to the more complex ones were proposed in the past to address the problem of foundations on elastic subgrades. Most of them are based on simplifying assumptions. With the objective of arriving at a reliable few-parameter analytical model, two- and single-parameter mechanical equivalents of a rigorous continuum foundation model proposed by the first author are presented that are adjusted with respect to the finite-element (FE) software, PLAXIS. The performance of both variants of the model is tested on beams by comparing with other analytical models and with FE models for a range of variables. Both variants performed remarkably well, especially the two-parameter variant. The adjusted model parameters are provided for practical use. Adjustment factors are also established for the popular Vlasov’s model. Comparison between the proposed and FE models shows that Vlasov’s adjustment factor is sensitive and varies over a comparatively wide range, and the model even becomes unadjustable for short beams. In contrast, the proposed models consistently yield very good results for all ranges of beams with an adjustment factor that is less sensitive and varying within a narrow range confirming their good quality.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"65 - 79"},"PeriodicalIF":1.3,"publicationDate":"2021-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47465986","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 : 2021-11-28DOI: 10.1080/17486025.2021.2008518
K. Tokgozoglu, Ç. Aladag, C. Gokceoglu
ABSTRACT The effect of overburden stress on the rock mass deformation modulus is a known issue. However, the effect of overburden stress has been studied less with empirical methods due to the lack of appropriate data. In this study, it is aimed to investigate the effect of overburden stress on rock mass deformation modulus using artificial neural network (ANN). Four ANN models have been developed in accordance with the purpose of the study. Two of these models do not contain the overburden stress parameter, but the other two models contain the overburden stress parameter. The prediction performance of the models containing the overburden stress parameter was obtained drastically higher than the others. In other words, the value account for (VAF) and root-mean-square error (RMSE) indices of the model having the inputs of rock mass rating (RMR) and elasticity modulus of intact rock (Ei) are 73.3% and 462, respectively, while those of the model having the inputs of RMR, Ei and overburden stress are 90% and 265. The other models developed in the present study yielded similar results. Consequently, with the ANN models developed in this study, the effect of overburden stress on Em is revealed, clearly.
{"title":"Artificial neural networks to predict deformation modulus of rock masses considering overburden stress","authors":"K. Tokgozoglu, Ç. Aladag, C. Gokceoglu","doi":"10.1080/17486025.2021.2008518","DOIUrl":"https://doi.org/10.1080/17486025.2021.2008518","url":null,"abstract":"ABSTRACT The effect of overburden stress on the rock mass deformation modulus is a known issue. However, the effect of overburden stress has been studied less with empirical methods due to the lack of appropriate data. In this study, it is aimed to investigate the effect of overburden stress on rock mass deformation modulus using artificial neural network (ANN). Four ANN models have been developed in accordance with the purpose of the study. Two of these models do not contain the overburden stress parameter, but the other two models contain the overburden stress parameter. The prediction performance of the models containing the overburden stress parameter was obtained drastically higher than the others. In other words, the value account for (VAF) and root-mean-square error (RMSE) indices of the model having the inputs of rock mass rating (RMR) and elasticity modulus of intact rock (Ei) are 73.3% and 462, respectively, while those of the model having the inputs of RMR, Ei and overburden stress are 90% and 265. The other models developed in the present study yielded similar results. Consequently, with the ANN models developed in this study, the effect of overburden stress on Em is revealed, clearly.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"48 - 64"},"PeriodicalIF":1.3,"publicationDate":"2021-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43067879","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 : 2021-11-02DOI: 10.1080/17486025.2021.1990420
A. Sinha, V. G. Havanagi, P. G. Sreekantan, S. Chandra
ABSTRACT Zinc tailing waste material is generated during the extraction of zinc metal. Its deposit is increasing year after year posing a threat to the environment and occupying large precious land. The present research explores the possibility of its application in road construction and filling. Physical and chemical tests were carried out, viz. SEM, EDS, X-ray diffraction and toxicity characteristics leachate procedure. The geotechnical characterisation was carried out and compared with similar types of materials, viz. soil and industrial wastes (fly ash and jarofix). Stress-settlement behaviour was studied by using a small scale physical model and validated by a numerical model test. Tailing was further mixed with cement to improve its properties for application in stabilised layers. Tailing is a porous, multi-phase and non-swelling cohesionless fine-grained material. It contains mainly oxides of silica, alumina, magnesium, calcium and less concentration of heavy metals. It has a high dry density (18.62 kN/m3), California Bearing Ratio (11%) and angle of internal friction (34°) compared to soil which makes it suitable for road construction. Cement stabilised tailing can be used in sub-base layer and can save about 170 mm thickness of the aggregate layer. Modulus value (18.17 MPa) indicates that it is a stiff material which leads to less settlement as a structural fill.
{"title":"Geotechnical characterisation of zinc tailing waste material for road construction","authors":"A. Sinha, V. G. Havanagi, P. G. Sreekantan, S. Chandra","doi":"10.1080/17486025.2021.1990420","DOIUrl":"https://doi.org/10.1080/17486025.2021.1990420","url":null,"abstract":"ABSTRACT Zinc tailing waste material is generated during the extraction of zinc metal. Its deposit is increasing year after year posing a threat to the environment and occupying large precious land. The present research explores the possibility of its application in road construction and filling. Physical and chemical tests were carried out, viz. SEM, EDS, X-ray diffraction and toxicity characteristics leachate procedure. The geotechnical characterisation was carried out and compared with similar types of materials, viz. soil and industrial wastes (fly ash and jarofix). Stress-settlement behaviour was studied by using a small scale physical model and validated by a numerical model test. Tailing was further mixed with cement to improve its properties for application in stabilised layers. Tailing is a porous, multi-phase and non-swelling cohesionless fine-grained material. It contains mainly oxides of silica, alumina, magnesium, calcium and less concentration of heavy metals. It has a high dry density (18.62 kN/m3), California Bearing Ratio (11%) and angle of internal friction (34°) compared to soil which makes it suitable for road construction. Cement stabilised tailing can be used in sub-base layer and can save about 170 mm thickness of the aggregate layer. Modulus value (18.17 MPa) indicates that it is a stiff material which leads to less settlement as a structural fill.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1984 - 2004"},"PeriodicalIF":1.3,"publicationDate":"2021-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46289559","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 : 2021-10-29DOI: 10.1080/17486025.2021.1992515
A. Hamidi, Mohammad Hajimohammadi
ABSTRACT The specimens of contaminated clay improved with Portland cement and lime were cured for seven days and were subjected to uniaxial compressive strength (UCS) testing. The results for anthracene-contaminated specimens improved with three percent Portland cement (by weight of clay) were approximately equivalent to those improved with 10% lime. The results for glycerol-contaminated specimens improved with nine percent Portland cement was approximately equivalent to that improved with 10% lime. According to the results, both Portland cement and lime were able to improve the clay soil contaminated with anthracene and glycerol, but Portland cement had a greater effect than lime on the anthracene-contaminated specimens because of the non-polar behaviour of anthracene and the grain-like (flocculated) behaviour of the contaminated soil. These factors were the result of a decrease in the diffuse double layer thickness by anthracene, which has a lower dielectric constant relative to water. The lime had a greater effect than cement on the specimens contaminated with glycerol because of the polar behaviour of glycerol, the increase in the required moisture content for hydration, and because the dielectric constant of glycerol is close to that of water. These results were evaluated and confirmed by scanning electron microscopy.
{"title":"Improving the mechanical behaviour of clay contaminated with glycerol and anthracene using lime and Portland cement","authors":"A. Hamidi, Mohammad Hajimohammadi","doi":"10.1080/17486025.2021.1992515","DOIUrl":"https://doi.org/10.1080/17486025.2021.1992515","url":null,"abstract":"ABSTRACT The specimens of contaminated clay improved with Portland cement and lime were cured for seven days and were subjected to uniaxial compressive strength (UCS) testing. The results for anthracene-contaminated specimens improved with three percent Portland cement (by weight of clay) were approximately equivalent to those improved with 10% lime. The results for glycerol-contaminated specimens improved with nine percent Portland cement was approximately equivalent to that improved with 10% lime. According to the results, both Portland cement and lime were able to improve the clay soil contaminated with anthracene and glycerol, but Portland cement had a greater effect than lime on the anthracene-contaminated specimens because of the non-polar behaviour of anthracene and the grain-like (flocculated) behaviour of the contaminated soil. These factors were the result of a decrease in the diffuse double layer thickness by anthracene, which has a lower dielectric constant relative to water. The lime had a greater effect than cement on the specimens contaminated with glycerol because of the polar behaviour of glycerol, the increase in the required moisture content for hydration, and because the dielectric constant of glycerol is close to that of water. These results were evaluated and confirmed by scanning electron microscopy.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"1 - 15"},"PeriodicalIF":1.3,"publicationDate":"2021-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42675832","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：