Pub Date : 2022-07-26DOI: 10.1080/17486025.2022.2103187
Suvendu Kumar Sasmal, R. Behera
ABSTRACT The present study focuses on estimating the transient response of shallow strip footing on granular soil using soft computing techniques. A shallow foundation is numerically modelled using Beam on Nonlinear Winkler Foundation model. Then the footing is subjected to a combination of allowable static and cyclic load depending on the ultimate bearing capacity of the footing. The eccentricity and angle of load inclination of static load are varied to simulate more practical conditions. The cyclic load is rectangular pulse load. One cycle of rectangular pulse load is applied to observe the immediate response of the foundation, referred as the transient response. Apart from the loading parameters, three granular soils of three different relative densities (D r = 35%, 51% and 69%) are considered. Based on numerical simulation of 1728 conditions, soft computing models are developed using five techniques, viz. Neural Networks, Support Vector Machines, Multivariate Adaptive Regression Splines, Adaptive Neuro Fuzzy Interface System and Multi Gene Genetic Programming. It is found that the static load on the foundation is the most important parameter controlling the transient response of the footing.
摘要本研究的重点是利用软计算技术估算颗粒土上浅条形基脚的瞬态响应。采用梁-非线性Winkler地基模型对浅基础进行了数值模拟。然后，根据基脚的极限承载力，基脚承受容许静态荷载和循环荷载的组合。改变静载荷的偏心率和载荷倾角，以模拟更实际的情况。循环载荷为矩形脉冲载荷。施加一个周期的矩形脉冲荷载，以观察基础的即时响应，称为瞬态响应。除荷载参数外，三种不同相对密度（D r = 35%、51%和69%）。在对1728个条件进行数值模拟的基础上，利用神经网络、支持向量机、多元自适应回归样条、自适应神经模糊接口系统和多基因遗传规划五种技术建立了软计算模型。研究发现，地基静载荷是控制地基瞬态响应的最重要参数。
{"title":"Transient settlement estimation of shallow foundation under eccentrically inclined static and cyclic load on granular soil using artificial intelligence techniques","authors":"Suvendu Kumar Sasmal, R. Behera","doi":"10.1080/17486025.2022.2103187","DOIUrl":"https://doi.org/10.1080/17486025.2022.2103187","url":null,"abstract":"ABSTRACT The present study focuses on estimating the transient response of shallow strip footing on granular soil using soft computing techniques. A shallow foundation is numerically modelled using Beam on Nonlinear Winkler Foundation model. Then the footing is subjected to a combination of allowable static and cyclic load depending on the ultimate bearing capacity of the footing. The eccentricity and angle of load inclination of static load are varied to simulate more practical conditions. The cyclic load is rectangular pulse load. One cycle of rectangular pulse load is applied to observe the immediate response of the foundation, referred as the transient response. Apart from the loading parameters, three granular soils of three different relative densities (D r = 35%, 51% and 69%) are considered. Based on numerical simulation of 1728 conditions, soft computing models are developed using five techniques, viz. Neural Networks, Support Vector Machines, Multivariate Adaptive Regression Splines, Adaptive Neuro Fuzzy Interface System and Multi Gene Genetic Programming. It is found that the static load on the foundation is the most important parameter controlling the transient response of the footing.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"560 - 576"},"PeriodicalIF":1.3,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49612838","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 : 2022-07-18DOI: 10.1080/17486025.2022.2096264
Armin Sahebkaram Alamdari, R. Dabiri, R. Jani, Fariba Behrouz Sarand
ABSTRACT Liquefaction in soil layers is a vital factor intensifying earthquake damages.This study compares the numerical evaluation process and the results of two methods based on stress and energy. It is inferred from the calculations that the stress-based method predicts a higher liquefaction potential with a lower safety factor as it promises liquefaction in deeper soil layers. In return, liquefaction tends to occur at a shallower depth with higher intensity in the energy-based method. Through applying the two approaches based on the data collected from different areas around Tabriz, a liquefaction-zoning map is presented. Despite being far from the fault, the central to the western and the southwestern parts of Tabriz has a high liquefaction potential. Eventually, based on the evaluated liquefaction potential using the stated methods and adopting the gene expression programming (GEP) approach, an equation is introduced to estimate the liquefaction potential for the case study. The predictions of the proposed models were consistent with the findings of experimental methods, demonstrating appropriate statistical measures and parametric analysis. It can also be concluded from the results of the parametric analysis, that the parameters of maximum acceleration, earthquake magnitude, and SPT number have more great impact on soil liquefaction.
{"title":"Evaluation of liquefaction potential by energy-based and stress-based methods and gene expressing programming (case study: Tabriz city)","authors":"Armin Sahebkaram Alamdari, R. Dabiri, R. Jani, Fariba Behrouz Sarand","doi":"10.1080/17486025.2022.2096264","DOIUrl":"https://doi.org/10.1080/17486025.2022.2096264","url":null,"abstract":"ABSTRACT Liquefaction in soil layers is a vital factor intensifying earthquake damages.This study compares the numerical evaluation process and the results of two methods based on stress and energy. It is inferred from the calculations that the stress-based method predicts a higher liquefaction potential with a lower safety factor as it promises liquefaction in deeper soil layers. In return, liquefaction tends to occur at a shallower depth with higher intensity in the energy-based method. Through applying the two approaches based on the data collected from different areas around Tabriz, a liquefaction-zoning map is presented. Despite being far from the fault, the central to the western and the southwestern parts of Tabriz has a high liquefaction potential. Eventually, based on the evaluated liquefaction potential using the stated methods and adopting the gene expression programming (GEP) approach, an equation is introduced to estimate the liquefaction potential for the case study. The predictions of the proposed models were consistent with the findings of experimental methods, demonstrating appropriate statistical measures and parametric analysis. It can also be concluded from the results of the parametric analysis, that the parameters of maximum acceleration, earthquake magnitude, and SPT number have more great impact on soil liquefaction.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"517 - 538"},"PeriodicalIF":1.3,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41992123","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 : 2022-07-16DOI: 10.1080/17486025.2022.2099019
Falk Ayub, S. Khan, Sarmishta Rudra Paul
ABSTRACT Herein a novel nanocomposite, Praseodymium oxide-nano montmorillonite (Pr-nMMT)was fabricated and explored as stabilising admixture for enhancing the strength of dredged soils. The compaction, permeability, direct shear, california bearing ratio (CBR), and unconfined compressive strength (UCS) tests performed on the dredged soil samples collected from the Shalimar site along the Dal Lake Srinagar rendered it unsuitable as construction material and needed stabilisation before using it as a building material. Different percentages of Pr-nMMT (0.25–1%) were used for stabilisation purposes and it revealed that the addition of Pr-nMMT to soil increased maximum dry density (MDD), shear strength parameters (angle of internal friction and cohesion), CBR, and decreased optimum moisture content (OMC), plasticity index, and hydraulic conductivity. The UCS enhanced notably with Pr-nMMT content and increment in curing time. The optimum Pr-nMMT content determined was 0.5% as it demonstrated the maximum value of UCS at 0, 7 and 14 days of curing beyond which the strength showed a declining trend. It was anticipated that Pr-nMMT filled pores between soil particles, therefore resisting sliding among soil particles and thus increasing the strength of treated dredged soil. The results portray Pr-nMMT as an efficient nano admixture for the stabilisation of dredged soil.
{"title":"Praseodymium-oxide decorated montmorillonite nanocomposite as a novel admixture for dredged soil stabilisation","authors":"Falk Ayub, S. Khan, Sarmishta Rudra Paul","doi":"10.1080/17486025.2022.2099019","DOIUrl":"https://doi.org/10.1080/17486025.2022.2099019","url":null,"abstract":"ABSTRACT Herein a novel nanocomposite, Praseodymium oxide-nano montmorillonite (Pr-nMMT)was fabricated and explored as stabilising admixture for enhancing the strength of dredged soils. The compaction, permeability, direct shear, california bearing ratio (CBR), and unconfined compressive strength (UCS) tests performed on the dredged soil samples collected from the Shalimar site along the Dal Lake Srinagar rendered it unsuitable as construction material and needed stabilisation before using it as a building material. Different percentages of Pr-nMMT (0.25–1%) were used for stabilisation purposes and it revealed that the addition of Pr-nMMT to soil increased maximum dry density (MDD), shear strength parameters (angle of internal friction and cohesion), CBR, and decreased optimum moisture content (OMC), plasticity index, and hydraulic conductivity. The UCS enhanced notably with Pr-nMMT content and increment in curing time. The optimum Pr-nMMT content determined was 0.5% as it demonstrated the maximum value of UCS at 0, 7 and 14 days of curing beyond which the strength showed a declining trend. It was anticipated that Pr-nMMT filled pores between soil particles, therefore resisting sliding among soil particles and thus increasing the strength of treated dredged soil. The results portray Pr-nMMT as an efficient nano admixture for the stabilisation of dredged soil.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"548 - 559"},"PeriodicalIF":1.3,"publicationDate":"2022-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45295735","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 : 2022-07-06DOI: 10.1080/17486025.2022.2096265
M. A. Farooqi, K. Ali, I. Shah, K. Alotaibi
ABSTRACT Micropiling is an extensively used method for improving the stability of building foundations and load-carrying capacity of the soil. Unlike regular piling, it can be employed without pile driving equipment and, hence, it is a versatile option of soil reinforcement under space-restricted situations. Since, it is an economical and easy to implement option for soil improvement, this paper intends to study the improvement in bearing capacity and settlement behaviour of a fly-ash bed using fine micropiles under isolated footings, for low-cast and lightweight structures. Fly-ash, a by-product of coal-fired power plants, is used in the experiment because it is extensively used as a filling material for housing projects in low-lying areas and pavements. Micropiles were installed underneath the footing as well as beyond the periphery of footing with varied spacing and extent ratio. The results are depicted through two dimensionless constants, namely bearing capacity ratio (BCR) and settlement reduction factor (SRF). Significant improvements have been observed in load-carrying capacity and settlement potential due to decrease in spacing and increase in lateral extent of micropiles. The optimum configuration of spacing and lateral extend achieved 135% bearing capacity improvement with 71% decrease in settlement.
{"title":"Effect on bearing capacity and settlement behaviour of fly-ash reinforced with fine micropiles","authors":"M. A. Farooqi, K. Ali, I. Shah, K. Alotaibi","doi":"10.1080/17486025.2022.2096265","DOIUrl":"https://doi.org/10.1080/17486025.2022.2096265","url":null,"abstract":"ABSTRACT Micropiling is an extensively used method for improving the stability of building foundations and load-carrying capacity of the soil. Unlike regular piling, it can be employed without pile driving equipment and, hence, it is a versatile option of soil reinforcement under space-restricted situations. Since, it is an economical and easy to implement option for soil improvement, this paper intends to study the improvement in bearing capacity and settlement behaviour of a fly-ash bed using fine micropiles under isolated footings, for low-cast and lightweight structures. Fly-ash, a by-product of coal-fired power plants, is used in the experiment because it is extensively used as a filling material for housing projects in low-lying areas and pavements. Micropiles were installed underneath the footing as well as beyond the periphery of footing with varied spacing and extent ratio. The results are depicted through two dimensionless constants, namely bearing capacity ratio (BCR) and settlement reduction factor (SRF). Significant improvements have been observed in load-carrying capacity and settlement potential due to decrease in spacing and increase in lateral extent of micropiles. The optimum configuration of spacing and lateral extend achieved 135% bearing capacity improvement with 71% decrease in settlement.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"539 - 547"},"PeriodicalIF":1.3,"publicationDate":"2022-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48941395","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 : 2022-07-04DOI: 10.1080/17486025.2021.1912405
U. El Shamy
ABSTRACT This paper presents a multiscale approach to analyse the seismic response of a spread-footing system founded on saturated granular soil deposits that might be susceptible to liquefaction. The pore-fluid is idealised as a continuum by using a homogenised form of Navier-Stokes equations that accounts for the presence of the solid particles. These particles are modelled at a microscale using the discrete element method. The foundation is idealised as a square rigid block by generating a group of glued particles. Computational simulations were conducted to investigate the response of spread-footings on saturated deposits when subjected to a seismic excitation. For the considered closely-spaced foundation system, it is possible to have a foundation settlement smaller than the free-field. Stress overlap between neighbouring footings could lead to an increase in soil stiffness and less susceptibility to pore-pressure build-up and volume decrease compared with the free-field. The majority of the foundation settlement occurs during shaking, whereas settlement continues to accumulate post shaking in the free-field. Evaluation of the contribution of base and lateral walls of the foundation to the lateral response of the footing showed that the predominant contributors were the base shear force and walls normal to the direction of shaking.
{"title":"Multiscale modelling of the seismic response of shallow foundations on saturated granular soils","authors":"U. El Shamy","doi":"10.1080/17486025.2021.1912405","DOIUrl":"https://doi.org/10.1080/17486025.2021.1912405","url":null,"abstract":"ABSTRACT This paper presents a multiscale approach to analyse the seismic response of a spread-footing system founded on saturated granular soil deposits that might be susceptible to liquefaction. The pore-fluid is idealised as a continuum by using a homogenised form of Navier-Stokes equations that accounts for the presence of the solid particles. These particles are modelled at a microscale using the discrete element method. The foundation is idealised as a square rigid block by generating a group of glued particles. Computational simulations were conducted to investigate the response of spread-footings on saturated deposits when subjected to a seismic excitation. For the considered closely-spaced foundation system, it is possible to have a foundation settlement smaller than the free-field. Stress overlap between neighbouring footings could lead to an increase in soil stiffness and less susceptibility to pore-pressure build-up and volume decrease compared with the free-field. The majority of the foundation settlement occurs during shaking, whereas settlement continues to accumulate post shaking in the free-field. Evaluation of the contribution of base and lateral walls of the foundation to the lateral response of the footing showed that the predominant contributors were the base shear force and walls normal to the direction of shaking.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"17 1","pages":"1073 - 1094"},"PeriodicalIF":1.3,"publicationDate":"2022-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/17486025.2021.1912405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60093215","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 : 2022-06-25DOI: 10.1080/17486025.2022.2090621
K. Onyelowe, F. Aneke, M. Onyia, A. Ebid, Thompson Usungedo
ABSTRACT AI-based bi-input predictive models have been executed to forecast the bulk density, linear and volumetric shrinkages and desiccation cracking of HSDA-treated black cotton soil (BCS) for sustainable subgrade construction purposes. The BCS was characterised and classified as A-7 group soil with high plasticity and poorly graded condition. Sawdust ash was obtained by combusting sawdust and sieving through 2.35 mm aperture sieve. It was further activated by blending it with pre-formulated activator material (a blend of 8 M NaOH solution and NaSiO2 in 1:1 ratio) to derive waste-based HSDA. The HSDA was further used in wt % of 3, 6, 9, and 12 to treat the BCS. The treated samples were compacted in the standard proctor moulds, cured for 24 h and extruded. The desiccation tests were then performed on the prepared specimens by drying them at a temp of 102°C for 30 days and behavioural changes in weight, height, diameter, average crack development, etc., were taken throughout the period. Multiple data sets were collected for the references test, and treated specimens of 3, 6, 9, and 12% wt HSDA of the soil for 30 drying days. XRF and SEM tests were also conducted to determine the pozzolanic strength via the chemical oxide composition, three chemical moduli (TCM) and the microstructural arrangement of the experimental materials and the treated BCS. The XRF tests showed that the experimental materials had less pozzolanic strength, which improved with the treated blends thereby forming stabilised mass of BCS. Also, it showed the silica moduli of the TCM dominated the stabilisation of the soil with waste-based HSDA. SEM tests showed increased formation of ettringite and gels with the addition of the HSDA. The data collected was subjected intelligent models’ prediction using ANN, GP and EPR for the four outcomes; BD, CW, LS and VS of the HSDA-treated BCS. The models’ performance showed that EPR outclassed the other techniques in predicting BD and CW with accuracies of 98.2% and 92.7% and minimal error, while ANN outclassed the other techniques in predicting LS and VS with accuracies of 98.8% and 99.3% and minimal error, respectively.
摘要基于人工智能的双输入预测模型已被用于预测HSDA处理的黑棉土（BCS）的体积密度、线性和体积收缩以及干燥开裂，以实现可持续的路基施工目的。BCS的特征和分类为A-7组土壤，具有高塑性和较差的级配条件。木屑灰是通过燃烧木屑并通过2.35筛分得到的 mm孔径筛。通过将其与预先配制的活化剂材料（8 M NaOH溶液和NaSiO2以1:1的比例）以得到基于废物的HSDA。HSDA进一步以重量%的3、6、9和12用于处理BCS。处理后的样品在标准普氏模具中压实，固化24小时 h并挤出。然后，通过在102°C的温度下干燥30，对制备的样品进行干燥试验 天数和重量、高度、直径、平均裂纹发展等方面的行为变化。为参考试验收集了多个数据集，并对3、6、9和12%wt HSDA的土壤样品进行了30天的干燥处理。还进行了XRF和SEM测试，通过实验材料和处理过的BCS的化学氧化物组成、三种化学模量（TCM）和微观结构排列来确定火山灰强度。XRF测试表明，实验材料的火山灰强度较低，经处理的共混物提高了火山灰强度，从而形成稳定质量的BCS。此外，它还表明TCM的二氧化硅模量主导了基于废物的HSDA对土壤的稳定。SEM测试表明，随着HSDA的加入，钙矾石和凝胶的形成增加。采用人工神经网络、GP和EPR对收集到的数据进行智能模型预测；HSDA处理的BCS的BD、CW、LS和VS。模型的性能表明，EPR在预测BD和CW方面优于其他技术，准确率分别为98.2%和92.7%，误差最小；而ANN在预测LS和VS方面优于其他方法，准确度分别为98.8%和99.3%，误差最小。
{"title":"AI (ANN, GP, and EPR)-based predictive models of bulk density, linear-volumetric shrinkage & desiccation cracking of HSDA-treated black cotton soil for sustainable subgrade","authors":"K. Onyelowe, F. Aneke, M. Onyia, A. Ebid, Thompson Usungedo","doi":"10.1080/17486025.2022.2090621","DOIUrl":"https://doi.org/10.1080/17486025.2022.2090621","url":null,"abstract":"ABSTRACT AI-based bi-input predictive models have been executed to forecast the bulk density, linear and volumetric shrinkages and desiccation cracking of HSDA-treated black cotton soil (BCS) for sustainable subgrade construction purposes. The BCS was characterised and classified as A-7 group soil with high plasticity and poorly graded condition. Sawdust ash was obtained by combusting sawdust and sieving through 2.35 mm aperture sieve. It was further activated by blending it with pre-formulated activator material (a blend of 8 M NaOH solution and NaSiO2 in 1:1 ratio) to derive waste-based HSDA. The HSDA was further used in wt % of 3, 6, 9, and 12 to treat the BCS. The treated samples were compacted in the standard proctor moulds, cured for 24 h and extruded. The desiccation tests were then performed on the prepared specimens by drying them at a temp of 102°C for 30 days and behavioural changes in weight, height, diameter, average crack development, etc., were taken throughout the period. Multiple data sets were collected for the references test, and treated specimens of 3, 6, 9, and 12% wt HSDA of the soil for 30 drying days. XRF and SEM tests were also conducted to determine the pozzolanic strength via the chemical oxide composition, three chemical moduli (TCM) and the microstructural arrangement of the experimental materials and the treated BCS. The XRF tests showed that the experimental materials had less pozzolanic strength, which improved with the treated blends thereby forming stabilised mass of BCS. Also, it showed the silica moduli of the TCM dominated the stabilisation of the soil with waste-based HSDA. SEM tests showed increased formation of ettringite and gels with the addition of the HSDA. The data collected was subjected intelligent models’ prediction using ANN, GP and EPR for the four outcomes; BD, CW, LS and VS of the HSDA-treated BCS. The models’ performance showed that EPR outclassed the other techniques in predicting BD and CW with accuracies of 98.2% and 92.7% and minimal error, while ANN outclassed the other techniques in predicting LS and VS with accuracies of 98.8% and 99.3% and minimal error, respectively.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"497 - 516"},"PeriodicalIF":1.3,"publicationDate":"2022-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49419066","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 : 2022-06-05DOI: 10.1080/17486025.2022.2083696
A. K. Jain, A. Jha, Ayush Kumar, Mohammad Shabib Akhtar
ABSTRACT The present works have been aimed to investigate the potential of marble dust (i.e. a waste material obtained as a by-product from the marble industry) as a replacement of sand to achieve the desired geotechnical properties for its possible use as a geomaterial. Hence, marble dust (MD) is amended with a wide range of Bentonite (B) content (up to 95%) to examine the geotechnical properties [i.e. Atterberg’s limits, free swell indexes, compaction characteristics, California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), and shear strength]. The efficacy and potential of MD-B mixes are confirmed by validating the geotechnical properties of sand (S)-bentonite (B) mixes. Results revealed that the geotechnical properties of MD-B mixes are observed to be comparable with S-B mixes. However, the amendment of MD and S with 60% B has been observed to be most beneficial in terms of achieving the ultimate CBR, UCS, and shear strength values. Thus, it is concluded that MD can be used as an alternative geomaterial to the sand with bentonite. Further, microanalyses [X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDAX), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Analysis (TA)] and physicochemical are performed to elucidate the results.
{"title":"Geotechnical properties and microanalyses of marble dust-bentonite as an alternative geomaterial of sand-bentonite mixes","authors":"A. K. Jain, A. Jha, Ayush Kumar, Mohammad Shabib Akhtar","doi":"10.1080/17486025.2022.2083696","DOIUrl":"https://doi.org/10.1080/17486025.2022.2083696","url":null,"abstract":"ABSTRACT The present works have been aimed to investigate the potential of marble dust (i.e. a waste material obtained as a by-product from the marble industry) as a replacement of sand to achieve the desired geotechnical properties for its possible use as a geomaterial. Hence, marble dust (MD) is amended with a wide range of Bentonite (B) content (up to 95%) to examine the geotechnical properties [i.e. Atterberg’s limits, free swell indexes, compaction characteristics, California Bearing Ratio (CBR), Unconfined Compressive Strength (UCS), and shear strength]. The efficacy and potential of MD-B mixes are confirmed by validating the geotechnical properties of sand (S)-bentonite (B) mixes. Results revealed that the geotechnical properties of MD-B mixes are observed to be comparable with S-B mixes. However, the amendment of MD and S with 60% B has been observed to be most beneficial in terms of achieving the ultimate CBR, UCS, and shear strength values. Thus, it is concluded that MD can be used as an alternative geomaterial to the sand with bentonite. Further, microanalyses [X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDAX), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Analysis (TA)] and physicochemical are performed to elucidate the results.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"477 - 496"},"PeriodicalIF":1.3,"publicationDate":"2022-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43990417","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 : 2022-05-27DOI: 10.1080/17486025.2022.2079154
Vibhoosha M P, A. Bhasi, S. Nayak
ABSTRACT Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. However, numerical modeling of geocell is always challenging due to its three-dimensional honeycomb structure. The limitations of the equivalent composite approach (ECA) led to the recent development of full 3D numerical models, which consider geocell-infill material interaction. This paper discusses the time-dependent performance of geocell-reinforced encased stone column-supported embankment considering the actual 3D nature of geocells using the finite element program ABAQUS. Parametric studies were carried out to study the stress transfer mechanism, vertical deformation of the foundation soil, and stress-strain variation inside the geocell pockets. It is found from the analyses that with the provision of a geocell layer on top of Geosynthetic Encased Stone Columns (GESC), the stress concentration ratio improved by 47% at the end of consolidation compared to GESC alone. Also, an 80% reduction in foundation surface settlement is observed with geocell-sand mattresses. The geocell-sand mattress decreased the bulging of the stone columns, and almost 80% of the stone column bulging occurred by the end of the embankment construction. The proposed model’s numerical results show that the equivalent composite approach overestimated the stress concentration ratio and bearing capacity. The tensile stresses are non-uniformly distributed in the geocell pockets, and the maximum tensile force was mobilised at the geocell mid-height. Among the various geocell infill materials analysed, the aggregates were best suited considering the stress concentration ratio and vertical settlement. The numerical results supported the idea that encased stone columns with geocells at the embankment base can perform similarly to a geosynthetic reinforced piled embankment system, which is costlier but very efficient. When the modular ratio is more than 40, geocell-reinforced encased stone column-supported embankment is similar to GRPES.
{"title":"Three dimensional analyses of geocell reinforced encased stone column supported embankments on lithomargic clay","authors":"Vibhoosha M P, A. Bhasi, S. Nayak","doi":"10.1080/17486025.2022.2079154","DOIUrl":"https://doi.org/10.1080/17486025.2022.2079154","url":null,"abstract":"ABSTRACT Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. However, numerical modeling of geocell is always challenging due to its three-dimensional honeycomb structure. The limitations of the equivalent composite approach (ECA) led to the recent development of full 3D numerical models, which consider geocell-infill material interaction. This paper discusses the time-dependent performance of geocell-reinforced encased stone column-supported embankment considering the actual 3D nature of geocells using the finite element program ABAQUS. Parametric studies were carried out to study the stress transfer mechanism, vertical deformation of the foundation soil, and stress-strain variation inside the geocell pockets. It is found from the analyses that with the provision of a geocell layer on top of Geosynthetic Encased Stone Columns (GESC), the stress concentration ratio improved by 47% at the end of consolidation compared to GESC alone. Also, an 80% reduction in foundation surface settlement is observed with geocell-sand mattresses. The geocell-sand mattress decreased the bulging of the stone columns, and almost 80% of the stone column bulging occurred by the end of the embankment construction. The proposed model’s numerical results show that the equivalent composite approach overestimated the stress concentration ratio and bearing capacity. The tensile stresses are non-uniformly distributed in the geocell pockets, and the maximum tensile force was mobilised at the geocell mid-height. Among the various geocell infill materials analysed, the aggregates were best suited considering the stress concentration ratio and vertical settlement. The numerical results supported the idea that encased stone columns with geocells at the embankment base can perform similarly to a geosynthetic reinforced piled embankment system, which is costlier but very efficient. When the modular ratio is more than 40, geocell-reinforced encased stone column-supported embankment is similar to GRPES.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"458 - 476"},"PeriodicalIF":1.3,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45895567","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 : 2022-04-29DOI: 10.1080/17486025.2022.2067595
B. Phanikumar, M. Shankar, M. D
ABSTRACT Landfill liners blended with industrial by-product seems to outperform the conventional liners. This paper presents the influence of sawdust (SD) admixed with bentonite and locally available lateritic soil on consistency limits, free swell index (FSI), compaction characteristics, unconfined compressive strength (UCS), hydraulic conductivity and leachate characteristics. SD content was varied as 10%, 15% and 20%. Diesel oil contaminants (DOC) and deionised water (DIW) were used as the test fluids. From the test results, consistency limits, FSI, maximum dry density, leachate concentration of heavy metals and UCS decreased, whereas optimum moisture content and hydraulic conductivity increased with increasing sawdust content. Furthermore, the energy-dispersive X-ray spectrometer revealed the absence of calcium in the blends which have resulted in poor cementation and decreased the UCS. X-ray diffraction showed that the presence of cellulose in sawdust and montmorillonite in bentonite adsorb the heavy metals in DOC. Based on the test results, 15% Saw dust content in the blends proves to be the optimum in retaining the heavy metal concentrations, improving the geotechnical properties and qualifying as a landfill liner material.
{"title":"Interaction of diesel oil contaminants with laterite soil and bentonite treated by sawdust -landfill liner","authors":"B. Phanikumar, M. Shankar, M. D","doi":"10.1080/17486025.2022.2067595","DOIUrl":"https://doi.org/10.1080/17486025.2022.2067595","url":null,"abstract":"ABSTRACT Landfill liners blended with industrial by-product seems to outperform the conventional liners. This paper presents the influence of sawdust (SD) admixed with bentonite and locally available lateritic soil on consistency limits, free swell index (FSI), compaction characteristics, unconfined compressive strength (UCS), hydraulic conductivity and leachate characteristics. SD content was varied as 10%, 15% and 20%. Diesel oil contaminants (DOC) and deionised water (DIW) were used as the test fluids. From the test results, consistency limits, FSI, maximum dry density, leachate concentration of heavy metals and UCS decreased, whereas optimum moisture content and hydraulic conductivity increased with increasing sawdust content. Furthermore, the energy-dispersive X-ray spectrometer revealed the absence of calcium in the blends which have resulted in poor cementation and decreased the UCS. X-ray diffraction showed that the presence of cellulose in sawdust and montmorillonite in bentonite adsorb the heavy metals in DOC. Based on the test results, 15% Saw dust content in the blends proves to be the optimum in retaining the heavy metal concentrations, improving the geotechnical properties and qualifying as a landfill liner material.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"441 - 457"},"PeriodicalIF":1.3,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41485320","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 : 2022-04-21DOI: 10.1080/17486025.2022.2065037
S. Zhang, A. Zsaki
ABSTRACT The discrete element method is often used in modelling of a variety of problems in granular materials. The shape and asperities of a particle affects the simulation outcome due to differences in collision behaviour. The differences can be significantly different for polyhedral particles. In this research, 3D scanning of rock fragments at various levels of geometric detail was used to determine the influence asperities and geometric detail. These particles were used in simulating the impact with a solid block and metrics were collected, including the time of initial contact, duration of contact and time of maximum force along with the magnitude of forces and impulse. The computational effort required was measured as well. It was found that the changes in geometry result in alteration of a particle’s extent, volume and surface area, leading to differences in the initial contact time and duration. The decreasing geometric detail yields differences up to 30% on average for a single collision alone. The particle resolution shows a lesser influence on the magnitude of the contact force and impulse. It can be concluded that about a few hundred elements are sufficient in representing a particle when considering the computational costs.
{"title":"Effect Geometric Detail on the Outcome of DEM Simulations with Polyhedral Particles","authors":"S. Zhang, A. Zsaki","doi":"10.1080/17486025.2022.2065037","DOIUrl":"https://doi.org/10.1080/17486025.2022.2065037","url":null,"abstract":"ABSTRACT The discrete element method is often used in modelling of a variety of problems in granular materials. The shape and asperities of a particle affects the simulation outcome due to differences in collision behaviour. The differences can be significantly different for polyhedral particles. In this research, 3D scanning of rock fragments at various levels of geometric detail was used to determine the influence asperities and geometric detail. These particles were used in simulating the impact with a solid block and metrics were collected, including the time of initial contact, duration of contact and time of maximum force along with the magnitude of forces and impulse. The computational effort required was measured as well. It was found that the changes in geometry result in alteration of a particle’s extent, volume and surface area, leading to differences in the initial contact time and duration. The decreasing geometric detail yields differences up to 30% on average for a single collision alone. The particle resolution shows a lesser influence on the magnitude of the contact force and impulse. It can be concluded that about a few hundred elements are sufficient in representing a particle when considering the computational costs.","PeriodicalId":46470,"journal":{"name":"Geomechanics and Geoengineering-An International Journal","volume":"18 1","pages":"426 - 439"},"PeriodicalIF":1.3,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48162561","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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