The stress-strain behaviour of 85 overconsolidated clay samples from Campo de Gibraltar Flysch Through Domain (Algeciras Unit, South Spain) is presented and discussed. The samples were identified and classified following ASTM standards while their chemical and mineralogical composition were determined by chemical and X-ray techniques. Several samples were tested under triaxial as well as oedometric conditions. Given the results, a detailed comparison was made between different theoretical constitutive models and real testing data, using the finite-elements method. The comparison indicated a good fit between experimental data and those found with finite-elements modelling when the Hardening Soil constitutive model was used. This model showed a better fit than did the Modified Cam- Clay model (historically used for modelling clayey soils), although the latter fit proved better for lower strain values (<5%) than higher ones. These results clarify this intermediate material (hard soils – weak rocks) behaviour and will help in Strait of Gibraltar tunnel project design, as these materials are widely involved in this tunnel design.
本文介绍并讨论了来自Campo de Gibraltar Flysch Through Domain (Algeciras Unit, South Spain)的85个超固结粘土样品的应力-应变行为。样品按照ASTM标准进行鉴定和分类，同时通过化学和x射线技术确定其化学和矿物学成分。几个样品在三轴和测量条件下进行了测试。在此基础上，采用有限元方法对不同理论本构模型与实际试验数据进行了详细比较。结果表明，采用硬化土本构模型时，实验数据与有限元模拟结果吻合较好。该模型显示出比修正Cam- Clay模型(历史上用于模拟黏性土壤)更好的拟合，尽管后者证明了较低应变值(<5%)比较高应变值更适合。这些结果澄清了中间材料(硬土-弱岩)的行为，并将有助于直布罗陀海峡隧道项目设计，因为这些材料广泛涉及该隧道设计。
{"title":"Overconsolidated flysch-type clays. Engineering considerations for the Strait of Gibraltar tunnel project","authors":"Francisco Manzano, F. Lamas, J. Azañón","doi":"10.28927/sr.2023.002222","DOIUrl":"https://doi.org/10.28927/sr.2023.002222","url":null,"abstract":"The stress-strain behaviour of 85 overconsolidated clay samples from Campo de Gibraltar Flysch Through Domain (Algeciras Unit, South Spain) is presented and discussed. The samples were identified and classified following ASTM standards while their chemical and mineralogical composition were determined by chemical and X-ray techniques. Several samples were tested under triaxial as well as oedometric conditions. Given the results, a detailed comparison was made between different theoretical constitutive models and real testing data, using the finite-elements method. The comparison indicated a good fit between experimental data and those found with finite-elements modelling when the Hardening Soil constitutive model was used. This model showed a better fit than did the Modified Cam- Clay model (historically used for modelling clayey soils), although the latter fit proved better for lower strain values (<5%) than higher ones. These results clarify this intermediate material (hard soils – weak rocks) behaviour and will help in Strait of Gibraltar tunnel project design, as these materials are widely involved in this tunnel design.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69268578","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}
The offshore industry has been challenged with the necessity to build structures with foundations on carbonate soils, found in extensive areas of the tropical and intertropical zones of the planet. As a better understanding of the behavior of these soils becomes more and more indispensable, this paper presents equations to predict the dynamic behavior of carbonate sands, in which two expressions (G/Gmax versus g and D versus g) were obtained via multiple linear regression using data from resonant column tests carried out on carbonate sands from Cabo Rojo, Puerto Rico (Cataño & Pando, 2010). The proposed equations agreed well with experimental data. The error for the expressions G/Gmax versus g was less than 10%, while the expressions D versus γ trended to underestimate the values for the loose condition (Dr = 24%), presenting an effective confining stress of 50kPa. Furthermore, the proposed equations were compared with predictions exhibited by Javdanian & Jafarian (2018) of G/Gmax versus g and D versus g for carbonate sands, also yielding fairly concordant results.
海洋工业面临的挑战是，必须在碳酸盐土壤上建造基础结构，而碳酸盐土壤位于地球上热带和热带间区的广大地区。为了更好地了解这些土壤的行为变得越来越必要，本文提出了预测碳酸盐岩砂动力行为的方程，其中使用波多黎各卡波罗霍碳酸盐岩砂进行的共振柱试验数据，通过多元线性回归得到了两个表达式(G/Gmax vs . G和D vs . G) (Cataño & Pando, 2010)。所提方程与实验数据吻合较好。G/Gmax相对于G的表达式误差小于10%，而D相对于γ的表达式倾向于低估松散条件下的值(Dr = 24%)，呈现50kPa的有效围应力。此外，将提出的方程与Javdanian和Jafarian(2018)对碳酸盐砂的G/Gmax与G和D与G的预测进行了比较，也得出了相当一致的结果。
{"title":"Proposition of correlations for the dynamic parameters of carbonate sands","authors":"Felipe Barroso, A. Moura","doi":"10.28927/sr.2023.001422","DOIUrl":"https://doi.org/10.28927/sr.2023.001422","url":null,"abstract":"The offshore industry has been challenged with the necessity to build structures with foundations on carbonate soils, found in extensive areas of the tropical and intertropical zones of the planet. As a better understanding of the behavior of these soils becomes more and more indispensable, this paper presents equations to predict the dynamic behavior of carbonate sands, in which two expressions (G/Gmax versus g and D versus g) were obtained via multiple linear regression using data from resonant column tests carried out on carbonate sands from Cabo Rojo, Puerto Rico (Cataño & Pando, 2010). The proposed equations agreed well with experimental data. The error for the expressions G/Gmax versus g was less than 10%, while the expressions D versus γ trended to underestimate the values for the loose condition (Dr = 24%), presenting an effective confining stress of 50kPa. Furthermore, the proposed equations were compared with predictions exhibited by Javdanian & Jafarian (2018) of G/Gmax versus g and D versus g for carbonate sands, also yielding fairly concordant results.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48595014","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}
This paper presents an experimental and numerical study for the effect of the cavity on the behaviour of a strip footing positioned on a reinforced sand slope. This study used a new type of geosynthetics called fiber carbon and fiber glass. These components have the potential to isolate the soil inside the geosynthetic and prevent shears stress mobilization. The investigation aimed to determine the effect of cavity depth (h) and the number of reinforcing layers (N) on the bearing capacity and settlement characteristics of footing, empirically for investigating the effect of cavity on the bearing capacity, some parameters were assumed constant in all tests, for example, relative density, a distance of the footing from the slope edge, and length between layers of reinforcement. The variable parameters are the distance between footings and centre of cavity and the number of reinforcing layers. The results show that the settlement behaviour of footing adjacent to a soil slope is significantly affected by h and N. It is observed that qu, which represents the ultimate bearing capacity, improves with an increase in N. The influence of the cavity appeared insignificant when it was positioned at a depth equal to twice the width of footing.
{"title":"The cavity’s effect on the bearing capacity of a shallow footing in reinforced slope sand","authors":"Bendaas Azeddine, Merdas Abdelghani","doi":"10.28927/sr.2023.003622","DOIUrl":"https://doi.org/10.28927/sr.2023.003622","url":null,"abstract":"This paper presents an experimental and numerical study for the effect of the cavity on the behaviour of a strip footing positioned on a reinforced sand slope. This study used a new type of geosynthetics called fiber carbon and fiber glass. These components have the potential to isolate the soil inside the geosynthetic and prevent shears stress mobilization. The investigation aimed to determine the effect of cavity depth (h) and the number of reinforcing layers (N) on the bearing capacity and settlement characteristics of footing, empirically for investigating the effect of cavity on the bearing capacity, some parameters were assumed constant in all tests, for example, relative density, a distance of the footing from the slope edge, and length between layers of reinforcement. The variable parameters are the distance between footings and centre of cavity and the number of reinforcing layers. The results show that the settlement behaviour of footing adjacent to a soil slope is significantly affected by h and N. It is observed that qu, which represents the ultimate bearing capacity, improves with an increase in N. The influence of the cavity appeared insignificant when it was positioned at a depth equal to twice the width of footing.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48334502","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}
The goal of this study was to improve the understanding of the soil-structure interaction mechanisms at the interface of bored concrete piles cast in sandy soils. In addition, this study aimed to quantify the interface shear strength and identify the factors that influence the response. Roughness measurements and direct shear tests were performed at the interface between two samples of sand (medium and coarse) and concrete cured under stress. The influence of the mean grain diameter, relative density, water content, concrete curing time and normal stress on the interface shear strength were statistically analyzed. The results showed a consistent behavior with the technical literature, but with higher values, which can be attributed to the concrete curing time, a factor not studied by other authors.
{"title":"Shear strength analysis of interfaces between granular soils and concrete cured under stress","authors":"A. Meier, V. Faro, E. Odebrecht","doi":"10.28927/sr.2023.004022","DOIUrl":"https://doi.org/10.28927/sr.2023.004022","url":null,"abstract":"The goal of this study was to improve the understanding of the soil-structure interaction mechanisms at the interface of bored concrete piles cast in sandy soils. In addition, this study aimed to quantify the interface shear strength and identify the factors that influence the response. Roughness measurements and direct shear tests were performed at the interface between two samples of sand (medium and coarse) and concrete cured under stress. The influence of the mean grain diameter, relative density, water content, concrete curing time and normal stress on the interface shear strength were statistically analyzed. The results showed a consistent behavior with the technical literature, but with higher values, which can be attributed to the concrete curing time, a factor not studied by other authors.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48389115","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}
The improper disposal of water treatment plant sludge (WTPS) into the environment can cause irreparable damage. One way to minimize this negative impact is to mix the sludge with the soil, applying the materials in engineering works. In this research, the objective was the use of WTPS for soil stabilization purposes, verifying the improvement of the characteristics and properties of a stabilized clay soil with different sludge percentages for application in waterproofing layers of bottom and final coverage of landfills. Formulations were prepared with additions of 0, 15, 30 and 50% of WTPS. Characterization, compaction, permeability and simple compression resistance tests were carried out. All mixtures met the Brazilian requirements for use in landfill layers, but the mixture composed of 70% soil + 30% WTPS was defined as the best for application in bottom layers and final coverage for the following reasons: it meets the coefficient of permeability and has the highest simple compression resistance of all blends. Furthermore, it is noteworthy that the use of the mixtures, especially 50% soil + 50% WTPS, in daily (intermediate) layers would be an environmentally beneficial alternative that would contribute to the circular economy and to achieving sustainable development goals 11, 12 and 15 by 2030. These applications would bring advantages in the destination of WTPS and reduced consumption of natural resources (soil).
{"title":"Study of the hydro-mechanical behavior of a stabilized soil with water treatment plant sludge for application in sanitary landfills","authors":"Elisangela Mazzutti, R. Klamt, V. Faro","doi":"10.28927/sr.2023.011222","DOIUrl":"https://doi.org/10.28927/sr.2023.011222","url":null,"abstract":"The improper disposal of water treatment plant sludge (WTPS) into the environment can cause irreparable damage. One way to minimize this negative impact is to mix the sludge with the soil, applying the materials in engineering works. In this research, the objective was the use of WTPS for soil stabilization purposes, verifying the improvement of the characteristics and properties of a stabilized clay soil with different sludge percentages for application in waterproofing layers of bottom and final coverage of landfills. Formulations were prepared with additions of 0, 15, 30 and 50% of WTPS. Characterization, compaction, permeability and simple compression resistance tests were carried out. All mixtures met the Brazilian requirements for use in landfill layers, but the mixture composed of 70% soil + 30% WTPS was defined as the best for application in bottom layers and final coverage for the following reasons: it meets the coefficient of permeability and has the highest simple compression resistance of all blends. Furthermore, it is noteworthy that the use of the mixtures, especially 50% soil + 50% WTPS, in daily (intermediate) layers would be an environmentally beneficial alternative that would contribute to the circular economy and to achieving sustainable development goals 11, 12 and 15 by 2030. These applications would bring advantages in the destination of WTPS and reduced consumption of natural resources (soil).","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2023-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47112166","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}
Alessandro Goldoni, Deise Pelissaro, Eriky Silveira, P. Prietto, Francisco Rosa
The application of alkali-activated industrial by-products for the stabilization of reclaimed asphalt pavement (RAP), can become a sustainable solution to reduce the carbon footprint of road construction and maintenance activities. Furthermore, this approach can also reduce the increasing depletion of natural resources. Thus, the durability and long-term mechanical performance of RAP stabilized with alkali-activated fly ash were assessed in this study. The alkaline activator was a solution composed of sodium hydroxide and sodium silicate. To this extent, unconfined compressive strength (UCS) and durability tests were conducted in this research. The proposed alkali-activated binder significantly increased the UCS of RAP mixtures, with long-term (365 days) results reaching values up to 32 MPa; fulfilling the strength requirements for cement-stabilized soil mixtures and even stable inorganic binder materials for road base and sub-base layers of pavements. These results indicate that when stabilized with an alkali-activated fly ash binder, RAP presents several applications for road engineering; even when subjected to seasonal variations in humidity and temperature, as shown by the durability tests.
{"title":"Durability and mechanical long-term performance of reclaimed asphalt pavement stabilized by alkali-activation","authors":"Alessandro Goldoni, Deise Pelissaro, Eriky Silveira, P. Prietto, Francisco Rosa","doi":"10.28927/sr.2023.007422","DOIUrl":"https://doi.org/10.28927/sr.2023.007422","url":null,"abstract":"The application of alkali-activated industrial by-products for the stabilization of reclaimed asphalt pavement (RAP), can become a sustainable solution to reduce the carbon footprint of road construction and maintenance activities. Furthermore, this approach can also reduce the increasing depletion of natural resources. Thus, the durability and long-term mechanical performance of RAP stabilized with alkali-activated fly ash were assessed in this study. The alkaline activator was a solution composed of sodium hydroxide and sodium silicate. To this extent, unconfined compressive strength (UCS) and durability tests were conducted in this research. The proposed alkali-activated binder significantly increased the UCS of RAP mixtures, with long-term (365 days) results reaching values up to 32 MPa; fulfilling the strength requirements for cement-stabilized soil mixtures and even stable inorganic binder materials for road base and sub-base layers of pavements. These results indicate that when stabilized with an alkali-activated fly ash binder, RAP presents several applications for road engineering; even when subjected to seasonal variations in humidity and temperature, as shown by the durability tests.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42652079","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}
Bismarck Oliveira, M. Sales, R. Angelim, Luiz Galvani Junior
The behavior of pile foundations under axial loading is directly influenced by the effects that its installation process induces in the surrounding soil. Consequently, the consideration of these effects is essential for the correct numerical modeling of these geotechnical structures. In the present study, numerical simulations of driven cast-in-situ piles under axial loading have been carried out using finite element analysis. Three 3.5 m long piles with diameters ranging from 114.3 to 219.1 mm were analyzed. The pile installation effects have been considered indirectly by employing two distinct approaches, both based on the concepts of cylindrical cavity expansion. The behavior of the tropical soil profile is described with the Hardening Soil constitutive model. The load-displacement response and load distribution along the pile obtained with the numerical simulations have been analyzed and compared with in-situ load tests results. In the failure conditions, both approaches accurately predicted the bearing capacity of the piles, with an average error of only 2% compared to the measured values. The results in terms of load distribution over depth were also satisfactory. The difference between measured and numerical ultimate base resistance values ranged from 0% to 30%. The good agreement between the numerical and experimental results indicates that the proposed numerical approaches have been effective in simulating the piles installation process and reinforces the importance of considering the installation effects in the numerical modeling of these geotechnical structures. Both approaches can also be used to predict the bearing capacity of displacement piles.
{"title":"Numerical simulations of displacement piles in a tropical soil","authors":"Bismarck Oliveira, M. Sales, R. Angelim, Luiz Galvani Junior","doi":"10.28927/sr.2023.004522","DOIUrl":"https://doi.org/10.28927/sr.2023.004522","url":null,"abstract":"The behavior of pile foundations under axial loading is directly influenced by the effects that its installation process induces in the surrounding soil. Consequently, the consideration of these effects is essential for the correct numerical modeling of these geotechnical structures. In the present study, numerical simulations of driven cast-in-situ piles under axial loading have been carried out using finite element analysis. Three 3.5 m long piles with diameters ranging from 114.3 to 219.1 mm were analyzed. The pile installation effects have been considered indirectly by employing two distinct approaches, both based on the concepts of cylindrical cavity expansion. The behavior of the tropical soil profile is described with the Hardening Soil constitutive model. The load-displacement response and load distribution along the pile obtained with the numerical simulations have been analyzed and compared with in-situ load tests results. In the failure conditions, both approaches accurately predicted the bearing capacity of the piles, with an average error of only 2% compared to the measured values. The results in terms of load distribution over depth were also satisfactory. The difference between measured and numerical ultimate base resistance values ranged from 0% to 30%. The good agreement between the numerical and experimental results indicates that the proposed numerical approaches have been effective in simulating the piles installation process and reinforces the importance of considering the installation effects in the numerical modeling of these geotechnical structures. Both approaches can also be used to predict the bearing capacity of displacement piles.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44961124","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}
M. Almeida, M. Marques, Mario Riccio, D. Fagundes, Bruno Lima, Uberescilas Polido, Alessandro Cirone, Iman Hosseinpour
Soft ground improvement techniques have evolved substantially in Brazil in recent years. However, their application in soft and very soft clays requires a good understanding of the fundamentals of ground improvement techniques suited to the problem as well as the actual field behavior when implemented on a real scale. This paper describes some of the most widely used ground improvement techniques in the context of very soft clays in Brazil. The techniques described in the paper use prefabricated vertical drains (PVD) such as vacuum preloading; or combine PVD and rigid inclusion, such as CPR grouting; or are purely column-like elements such as piled embankments (including those executed with the deep mixing technique, DSM); or combine column-like elements with the drainage function, such as stone columns and geosynthetic encased columns; or use cementitious binders such as shallow soil mixing. The paper reference condition is a soft clay foundation in which no strengthening is implemented, such as, an embankment with basal reinforcement or soft clay with vertical prefabricated drains, or the use of vacuum preloading to speed up the consolidation rate. The applications of the ground improvement techniques are illustrated by case histories, numerical analyses, or physical models. Different types of measurements are used to evaluate the performance of each technique, including settlements, horizontal displacements, excess pore pressures, embankment applied stresses, stress concentration factors, and clay strength following the ground treatment. The settlement improvement factor β, the ratio between the settlements for untreated and treated conditions, is shown to be a suitable parameter to assess the degree of improvement imposed in the soft foundation by ranking the various methods in increased order of strengthening effect.
{"title":"Ground improvement techniques applied to very soft clays: state of knowledge and recent advances","authors":"M. Almeida, M. Marques, Mario Riccio, D. Fagundes, Bruno Lima, Uberescilas Polido, Alessandro Cirone, Iman Hosseinpour","doi":"10.28927/sr.2023.008222","DOIUrl":"https://doi.org/10.28927/sr.2023.008222","url":null,"abstract":"Soft ground improvement techniques have evolved substantially in Brazil in recent years. However, their application in soft and very soft clays requires a good understanding of the fundamentals of ground improvement techniques suited to the problem as well as the actual field behavior when implemented on a real scale. This paper describes some of the most widely used ground improvement techniques in the context of very soft clays in Brazil. The techniques described in the paper use prefabricated vertical drains (PVD) such as vacuum preloading; or combine PVD and rigid inclusion, such as CPR grouting; or are purely column-like elements such as piled embankments (including those executed with the deep mixing technique, DSM); or combine column-like elements with the drainage function, such as stone columns and geosynthetic encased columns; or use cementitious binders such as shallow soil mixing. The paper reference condition is a soft clay foundation in which no strengthening is implemented, such as, an embankment with basal reinforcement or soft clay with vertical prefabricated drains, or the use of vacuum preloading to speed up the consolidation rate. The applications of the ground improvement techniques are illustrated by case histories, numerical analyses, or physical models. Different types of measurements are used to evaluate the performance of each technique, including settlements, horizontal displacements, excess pore pressures, embankment applied stresses, stress concentration factors, and clay strength following the ground treatment. The settlement improvement factor β, the ratio between the settlements for untreated and treated conditions, is shown to be a suitable parameter to assess the degree of improvement imposed in the soft foundation by ranking the various methods in increased order of strengthening effect.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43104008","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}
The improvement of sandy soils by incorporating new stabilizing agents in a physical and/or chemical process has become the subject of many studies in recent decades. In addition, the use of industrial wastes in this process can bring significant benefits to the environment and savings in natural resources. This work aims to evaluate the implications of incorporating porcelain polishing waste (PPW) and hydrated lime on the mechanical properties of an aeolian dune sand from the city of Natal/RN. Tests of unconfined compressive strength and split tensile strength were performed on compacted soil specimens with different contents of PPW (10%, 20% and 30%), hydrated lime (3%, 5% and 7%) and relative densities (25%, 50% and 75%). To evaluate the effects of each factor, the Response Surface Methodology with Central Composite Design was used. The results have shown that all three factors have a positive effect on the response variables. The highest strengths were obtained in regions combining high values of relative density and PPW content and an optimum lime content was found. An inversely proportional correlation and good fit to the experimental data was obtained between the strength values and the porosity/binder index (η / Biv). The strength gains were attributed to densification of the soil structure and cementation of the particles by the compounds formed in the reaction between lime and PPW. The results also showed an increase in the strength with curing time, indicating a pozzolanic activity of the mixtures.
{"title":"Compressive and tensile strength of aeolian sand stabilized with porcelain polishing waste and hydrated lime","authors":"José Silva, Olavo F. dos Santos Júnior, W. Paiva","doi":"10.28927/sr.2023.002322","DOIUrl":"https://doi.org/10.28927/sr.2023.002322","url":null,"abstract":"The improvement of sandy soils by incorporating new stabilizing agents in a physical and/or chemical process has become the subject of many studies in recent decades. In addition, the use of industrial wastes in this process can bring significant benefits to the environment and savings in natural resources. This work aims to evaluate the implications of incorporating porcelain polishing waste (PPW) and hydrated lime on the mechanical properties of an aeolian dune sand from the city of Natal/RN. Tests of unconfined compressive strength and split tensile strength were performed on compacted soil specimens with different contents of PPW (10%, 20% and 30%), hydrated lime (3%, 5% and 7%) and relative densities (25%, 50% and 75%). To evaluate the effects of each factor, the Response Surface Methodology with Central Composite Design was used. The results have shown that all three factors have a positive effect on the response variables. The highest strengths were obtained in regions combining high values of relative density and PPW content and an optimum lime content was found. An inversely proportional correlation and good fit to the experimental data was obtained between the strength values and the porosity/binder index (η / Biv). The strength gains were attributed to densification of the soil structure and cementation of the particles by the compounds formed in the reaction between lime and PPW. The results also showed an increase in the strength with curing time, indicating a pozzolanic activity of the mixtures.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46434131","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}
K. Rammah, Mostafa Ismail, J. Costa, Mario Riccio Filho
Seismic tomography has been extensively used in geophysics for different purposes, including geological mapping, characterisation of inner earth structure and prospecting for oil and gas. In geophysics, seismic or electromagnetic waves are commonly used to provide tomographic information. In the geotechnical area, seismic tomography is emerging as a promising technique that can be used to determine the spatial variability of shear wave velocities and hence the small strain stiffness of geomaterials, especially when used in the centrifuge where in-situ stress conditions can be mimicked closely. This paper describes the development of a seismic tomography technique in the centrifuge. This technology can be used to image variations of soil stiffness under various mechanical, chemical and physical conditions. The paper describes the various components of the system, which includes arrays of small-size bender elements, hardware and software used to transmit, receive and acquire the shear wave signals during a centrifuge test. The paper illustrates the performance of the system at both 1g and in the centrifuge. Results of tomographic inversion performed on travel-time data obtained from these tests are discussed.
{"title":"A new seismic tomography system for geotechnical centrifuges","authors":"K. Rammah, Mostafa Ismail, J. Costa, Mario Riccio Filho","doi":"10.28927/sr.2023.000922","DOIUrl":"https://doi.org/10.28927/sr.2023.000922","url":null,"abstract":"Seismic tomography has been extensively used in geophysics for different purposes, including geological mapping, characterisation of inner earth structure and prospecting for oil and gas. In geophysics, seismic or electromagnetic waves are commonly used to provide tomographic information. In the geotechnical area, seismic tomography is emerging as a promising technique that can be used to determine the spatial variability of shear wave velocities and hence the small strain stiffness of geomaterials, especially when used in the centrifuge where in-situ stress conditions can be mimicked closely. This paper describes the development of a seismic tomography technique in the centrifuge. This technology can be used to image variations of soil stiffness under various mechanical, chemical and physical conditions. The paper describes the various components of the system, which includes arrays of small-size bender elements, hardware and software used to transmit, receive and acquire the shear wave signals during a centrifuge test. The paper illustrates the performance of the system at both 1g and in the centrifuge. Results of tomographic inversion performed on travel-time data obtained from these tests are discussed.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45023684","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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