Residual loads can affect the load transfer and the settlement-induced in-service loadings, although they do not alter the bearing capacity. When residual loads are present and not measured or evaluated, the settlement estimate is greater than predicted if these loads are known. Residual loads can be measured when the pile instrumentation is nullified before pile installation, in the case of displacement piles, or before the first loading in non-displacement piles, such as bored cast-in-place piles, continuous flight auger piles, and micro-piles. In the case of underpinning foundation and piled raft, when the loading transfer is shared by the original and new foundation, or by the piles and the raft, it is essential to know the stiffness of each foundation element to estimate the load partition. If residual loads are present, pile stiffness is greater than when not considered in the design. The paper revisits this theme of practical relevance. A historical review of the most relevant research involving pile residual load measurements, pile loading tests including the interpretation of residual loads locked at a pile toe, and a new procedure for residual loads prediction are provided. A comparison is made of the experimental residual loads observed in some of the instrumented cases and the values estimated with the suggested procedure. The development of residual loads at the pile toe as a function of the toe resistance to total capacity ratio is very similar to the variation of the soil density as a function of soil moisture content in soil compaction.
{"title":"The 2022 Pacheco Silva lecture: The influence of residual loads on pile foundation behavior","authors":"B. Danziger","doi":"10.28927/sr.2023.002523","DOIUrl":"https://doi.org/10.28927/sr.2023.002523","url":null,"abstract":"Residual loads can affect the load transfer and the settlement-induced in-service loadings, although they do not alter the bearing capacity. When residual loads are present and not measured or evaluated, the settlement estimate is greater than predicted if these loads are known. Residual loads can be measured when the pile instrumentation is nullified before pile installation, in the case of displacement piles, or before the first loading in non-displacement piles, such as bored cast-in-place piles, continuous flight auger piles, and micro-piles. In the case of underpinning foundation and piled raft, when the loading transfer is shared by the original and new foundation, or by the piles and the raft, it is essential to know the stiffness of each foundation element to estimate the load partition. If residual loads are present, pile stiffness is greater than when not considered in the design. The paper revisits this theme of practical relevance. A historical review of the most relevant research involving pile residual load measurements, pile loading tests including the interpretation of residual loads locked at a pile toe, and a new procedure for residual loads prediction are provided. A comparison is made of the experimental residual loads observed in some of the instrumented cases and the values estimated with the suggested procedure. The development of residual loads at the pile toe as a function of the toe resistance to total capacity ratio is very similar to the variation of the soil density as a function of soil moisture content in soil compaction.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45384869","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 prediction of load capacity and the control of the execution of the Continuous Flight Auger (CFA) piles are often exercised with components of empiricism and intuition. This fact is often added to the uncertainties arising from the formation of the soils and the limitations of preliminary studies that support the project design. In this context, aiming to aid the executive control of CFA, a semi-empirical method is proposed based on the soil type, geometric dimensions of the piles, and the installation energy obtained during the pile excavation. The method makes it possible to determine the CFA pile load capacity during the execution process of each pile of pilling. As a consequence of the proposed method, the settlement of each pile can be controlled through the quantification of the energy required or the work carried out to excavate each pile through a specific software installed in the machinery monitoring system that increases the safety and reliability of the piling.
{"title":"Semi-empirical method for the bearing capacity of continuous flight auger piles based on installation energy","authors":"C. Silva, José Camapum de Carvalho","doi":"10.28927/sr.2023.012522","DOIUrl":"https://doi.org/10.28927/sr.2023.012522","url":null,"abstract":"The prediction of load capacity and the control of the execution of the Continuous Flight Auger (CFA) piles are often exercised with components of empiricism and intuition. This fact is often added to the uncertainties arising from the formation of the soils and the limitations of preliminary studies that support the project design. In this context, aiming to aid the executive control of CFA, a semi-empirical method is proposed based on the soil type, geometric dimensions of the piles, and the installation energy obtained during the pile excavation. The method makes it possible to determine the CFA pile load capacity during the execution process of each pile of pilling. As a consequence of the proposed method, the settlement of each pile can be controlled through the quantification of the energy required or the work carried out to excavate each pile through a specific software installed in the machinery monitoring system that increases the safety and reliability of the piling.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47421769","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}
Non-destructive tests (NDT) are used to verify the length or integrity of elements embedded in soils or rocks. These elements can be piles in foundations or nails and tiebacks in retaining walls. NDTs differ by the types of waves, ways to generate and receive the signal and to analyze data. Tests using sonic wave do not require a pre-installed pipe or wire and they are based on acoustic impedance theory. Despite its dissemination on piles, the application in retaining elements is recent and requires more studies to increase knowledge about these methods. This paper aims to present studies of sonic wave methods in foundation and retaining elements, presenting results, similarities, and differences. Studies from different dates are presented with their relevance, considerations for the different types of elements tested, objectives and methodologies used, to evidence the variables involved within this solution. The sonic test in foundation is widespread and has a greater number of studies. Withing this paper, the variables that interfere in the results of these methods were observed: the velocity of propagation of the sonic wave, the soil stiffness, the location of wave generation and reception and the type of hammer used, evidencing the necessity of further studies, especially in retaining elements.
{"title":"Use of longitudinal wave in non-destructive methods: approach to foundation and retaining elements","authors":"Isabela Silva, V. Faro","doi":"10.28927/sr.2023.013222","DOIUrl":"https://doi.org/10.28927/sr.2023.013222","url":null,"abstract":"Non-destructive tests (NDT) are used to verify the length or integrity of elements embedded in soils or rocks. These elements can be piles in foundations or nails and tiebacks in retaining walls. NDTs differ by the types of waves, ways to generate and receive the signal and to analyze data. Tests using sonic wave do not require a pre-installed pipe or wire and they are based on acoustic impedance theory. Despite its dissemination on piles, the application in retaining elements is recent and requires more studies to increase knowledge about these methods. This paper aims to present studies of sonic wave methods in foundation and retaining elements, presenting results, similarities, and differences. Studies from different dates are presented with their relevance, considerations for the different types of elements tested, objectives and methodologies used, to evidence the variables involved within this solution. The sonic test in foundation is widespread and has a greater number of studies. Withing this paper, the variables that interfere in the results of these methods were observed: the velocity of propagation of the sonic wave, the soil stiffness, the location of wave generation and reception and the type of hammer used, evidencing the necessity of further studies, especially in retaining elements.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44492557","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 use of geosynthetic clay liners (GCLs) as a hydraulic barrier for contaminants containment has proved to be an efficient alternative for the soil and groundwater protection. This geocomposite can be used in engineering systems to contain accidental spills and leaks of fuel in distribution centers, reservoirs and resulting from transport, where the geosynthetic acts as a protection against subsoil contamination. However, there is a concern about the behavior of GCLs in the face of these contaminants about possible changes in their properties, in order to compromise the retention capacity and permeability of the material. In this regard, the present work aimed to carry out a systemic and bibliometric study of publications related to the hydraulic conductivity of GCLs after contact with some type of fuel, available in the Scopus database (Elsevier) and Web of Science (Clarivate). The primary data selected directly from the databases were analyzed, making it possible to filter the publications that made up the bibliographic portfolio of the research, resulting in 14 selected documents, which were synthesized, and the main points were highlighted. From the bibliographic portfolio, bibliometric indexes of scientific production were created, as well as the temporal distribution of publications, authors, countries, and scientific journals that most contribute to the theme and the terms most evidenced in the documents. The panorama observed through bibliometrics was that it is a very recent theme, which still has a lack of scientific production, revealing itself as a promising area for the development of research.
{"title":"The hydraulic conductivity of fuel permeated geosynthetic clay liners: a bibliometric study","authors":"Julia Favretto, A. Braun, M. Floss, P. Prietto","doi":"10.28927/sr.2023.012222","DOIUrl":"https://doi.org/10.28927/sr.2023.012222","url":null,"abstract":"The use of geosynthetic clay liners (GCLs) as a hydraulic barrier for contaminants containment has proved to be an efficient alternative for the soil and groundwater protection. This geocomposite can be used in engineering systems to contain accidental spills and leaks of fuel in distribution centers, reservoirs and resulting from transport, where the geosynthetic acts as a protection against subsoil contamination. However, there is a concern about the behavior of GCLs in the face of these contaminants about possible changes in their properties, in order to compromise the retention capacity and permeability of the material. In this regard, the present work aimed to carry out a systemic and bibliometric study of publications related to the hydraulic conductivity of GCLs after contact with some type of fuel, available in the Scopus database (Elsevier) and Web of Science (Clarivate). The primary data selected directly from the databases were analyzed, making it possible to filter the publications that made up the bibliographic portfolio of the research, resulting in 14 selected documents, which were synthesized, and the main points were highlighted. From the bibliographic portfolio, bibliometric indexes of scientific production were created, as well as the temporal distribution of publications, authors, countries, and scientific journals that most contribute to the theme and the terms most evidenced in the documents. The panorama observed through bibliometrics was that it is a very recent theme, which still has a lack of scientific production, revealing itself as a promising area for the development of research.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44968834","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}
Water jet-driving technique has been shown as a viable practice for driving prefabricated piles in resistant soil layers. However, this technique is also associated with the reduction of load capacity of piles. Along these lines, the use of reams in prefabricated concrete piles improves their mechanical performance. The main objective of this research was to study the efficiency of reams on water jet-driven concrete piles; to this extent, pile loading tests and mini-cone tests were carried out before and after the driving of the piles. In addition, numerical modelling with the finite element method (FEM) was applied to study the stress-strain behavior. By means of the numerical modelling, it was possible to identify the stress and strain distribution at the tip, shaft, and reams of the piles; this allowed the understanding of the contribution of these elements in the total load capacity. Results have shown that the reams directly contribute for load capacity, with increases up to 40% when compared to conventional piles. Laboratory tests and numerical modeling proved to be fundamental tools to understand the mechanisms behind the contribution of reams to the load capacity of piles.
{"title":"Mechanical and numerical behavior of water jet-driven under-reamed concrete piles","authors":"C. Ruver, G. Bruschi","doi":"10.28927/sr.2023.012822","DOIUrl":"https://doi.org/10.28927/sr.2023.012822","url":null,"abstract":"Water jet-driving technique has been shown as a viable practice for driving prefabricated piles in resistant soil layers. However, this technique is also associated with the reduction of load capacity of piles. Along these lines, the use of reams in prefabricated concrete piles improves their mechanical performance. The main objective of this research was to study the efficiency of reams on water jet-driven concrete piles; to this extent, pile loading tests and mini-cone tests were carried out before and after the driving of the piles. In addition, numerical modelling with the finite element method (FEM) was applied to study the stress-strain behavior. By means of the numerical modelling, it was possible to identify the stress and strain distribution at the tip, shaft, and reams of the piles; this allowed the understanding of the contribution of these elements in the total load capacity. Results have shown that the reams directly contribute for load capacity, with increases up to 40% when compared to conventional piles. Laboratory tests and numerical modeling proved to be fundamental tools to understand the mechanisms behind the contribution of reams to the load capacity of piles.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47178174","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 study presents case studies on the implementation of an innovative method of calculating effective driving energy with no need to account for hammer efficiency. The approach is based on measurements of set and elastic rebound, as well as a site-specific parameter (λ) calibration. The study applied this method to steel piles located in the cities of Santos (SP), Itaguaí (RJ), and Óbidos (PA), with the latter site being built in the Amazon region, near the Amazon River. Following coefficient calibration, the effective driving energy estimation technique exhibited a strong correlation with realistic and accurate energies directly obtained from dynamic loading tests. The method provides a highly accurate means of calculating effectively transferred energy to piles due to hammer blows, without relying on knowledge of the driving system performance. In that way, it can be applied to all the piles at the site (100% of them), including those that are not tested. This optimized and agile approach represents a significant breakthrough in foundation engineering and an enhance of pile foundation quality control.
{"title":"Predicting driving transferred energy without needing the hammer efficiency: three case studies","authors":"André Querelli, T. Souza","doi":"10.28927/sr.2023.000223","DOIUrl":"https://doi.org/10.28927/sr.2023.000223","url":null,"abstract":"This study presents case studies on the implementation of an innovative method of calculating effective driving energy with no need to account for hammer efficiency. The approach is based on measurements of set and elastic rebound, as well as a site-specific parameter (λ) calibration. The study applied this method to steel piles located in the cities of Santos (SP), Itaguaí (RJ), and Óbidos (PA), with the latter site being built in the Amazon region, near the Amazon River. Following coefficient calibration, the effective driving energy estimation technique exhibited a strong correlation with realistic and accurate energies directly obtained from dynamic loading tests. The method provides a highly accurate means of calculating effectively transferred energy to piles due to hammer blows, without relying on knowledge of the driving system performance. In that way, it can be applied to all the piles at the site (100% of them), including those that are not tested. This optimized and agile approach represents a significant breakthrough in foundation engineering and an enhance of pile foundation quality control.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":"24 35","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41260800","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}
Renathielly Brunetta, A. Kormann, J. Gubaua, J. Pereira
The geomechanical behavior of a salt rock cavern was studied using Brazilian geotechnical properties. To design the finite element model, it was necessary to implement, using Fortran language, a constitutive model representing the creep behavior, since the model used is not native to the program. The constitutive model implemented was the Multiple Deformation Mechanism Model. This model was chosen for being a robust model that represents the primary and secondary phases of creep and presents good agreement with the Brazilian salt rocks. The analyzes considered a period of 50 years after the mine closure and five internal pressures acting in the analyzed cave. The pressures considered correspond to 40%, 50%, 60%, 70% and 80% of the vertical stress at the top of the mine. The creep and dilation behaviors were analyzed, and the creep deformations obtained in the simulations was acceptable in relation to the failure criterion adopted in this paper. However, only the design of experiment that considered the two biggest internal pressure resulted in a permissible micro-crack ratio value.
{"title":"Analysis of the creep and dilatant behavior of a salt cavern in long-term using Brazilian geotechnical properties","authors":"Renathielly Brunetta, A. Kormann, J. Gubaua, J. Pereira","doi":"10.28927/sr.2023.006722","DOIUrl":"https://doi.org/10.28927/sr.2023.006722","url":null,"abstract":"The geomechanical behavior of a salt rock cavern was studied using Brazilian geotechnical properties. To design the finite element model, it was necessary to implement, using Fortran language, a constitutive model representing the creep behavior, since the model used is not native to the program. The constitutive model implemented was the Multiple Deformation Mechanism Model. This model was chosen for being a robust model that represents the primary and secondary phases of creep and presents good agreement with the Brazilian salt rocks. The analyzes considered a period of 50 years after the mine closure and five internal pressures acting in the analyzed cave. The pressures considered correspond to 40%, 50%, 60%, 70% and 80% of the vertical stress at the top of the mine. The creep and dilation behaviors were analyzed, and the creep deformations obtained in the simulations was acceptable in relation to the failure criterion adopted in this paper. However, only the design of experiment that considered the two biggest internal pressure resulted in a permissible micro-crack ratio value.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48392413","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}
Ronald Mejia Sanchez, José Araruna Júnior, R. Avillez, Hongtao Wang, Shuguang Liu
The electrokinetic process seems to be interesting to the earthwork portion on the construction of buildings, and transportation projects since this simple, fast, yet reliable technique could expedite dehydrating of soil and reduce delays in the construction schedule. This paper examined the technical feasibility and a brief cost analysis of using plastic electrodes for electrokinetically dehydrating clayey soils with high moisture content were also carried out. The results from the experimental program carried out on a marine clayey soil with copper and plastic electrodes showed a great deal of soil improvement since positive changes in undrained shear strength occur due to the free water dehydration process induced by electroosmosis and to the adsorbed water dehydration process induced by electromigration. It was also observed that values of the undrained shear strength remained stable at the final stages of the electrokinetic process indicating a permanent soil improvement. Finally, it was noticed that dehydrating could be achieved at lower costs by employing plastic electrodes.
{"title":"Dehydrating subsurface clayey soils using plastic electrodes: a simple, fast, and yet reliable technique","authors":"Ronald Mejia Sanchez, José Araruna Júnior, R. Avillez, Hongtao Wang, Shuguang Liu","doi":"10.28927/sr.2023.074721","DOIUrl":"https://doi.org/10.28927/sr.2023.074721","url":null,"abstract":"The electrokinetic process seems to be interesting to the earthwork portion on the construction of buildings, and transportation projects since this simple, fast, yet reliable technique could expedite dehydrating of soil and reduce delays in the construction schedule. This paper examined the technical feasibility and a brief cost analysis of using plastic electrodes for electrokinetically dehydrating clayey soils with high moisture content were also carried out. The results from the experimental program carried out on a marine clayey soil with copper and plastic electrodes showed a great deal of soil improvement since positive changes in undrained shear strength occur due to the free water dehydration process induced by electroosmosis and to the adsorbed water dehydration process induced by electromigration. It was also observed that values of the undrained shear strength remained stable at the final stages of the electrokinetic process indicating a permanent soil improvement. Finally, it was noticed that dehydrating could be achieved at lower costs by employing plastic electrodes.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48259790","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 mechanical behavior of municipal solid waste (MSW) is a critical issue in environmental geotechnics, given the pollution and public health risks associated with slope failures. In Brazil, waste composition is expected to change due to the hierarchy of sustainable practices established by the National Solid Waste Policy, which aims to improve the recovery of organic and recyclable materials. Not much progress has been made since the implementation of this law; thus, its effects on the design and operation of landfills are not fully clear. This study presents and discusses compaction and shear strength parameters of dry MSW after mechanical sorting of medium and large recyclable items and shredding. The maximum dry unit weight for the standard Proctor compaction test ranged from 6.6 to 10.0 kN/m3 and the optimum moisture content ranged from 20% to 42%. Stress-displacement curves of direct shear tests showed strain hardening and shear strength parameters of Mohr-Coulomb envelopes were displacement-dependent. The friction angle ranged from 3.2° to 42.9° and the cohesion intercept ranged from 1.3 to 31.3 kPa, at a displacement of 9 mm (15% of the specimen length). These results are in line with the literature, since a high content of waste materials that proved to affect geotechnical properties, such as plastic, paper, cardboard, textile, and glass, remained after pre-treatment.
{"title":"Shear strength of municipal solid waste rejected from material recovery facilities in the city of São Paulo, Brazil","authors":"M. Juarez, G. Mondelli, H. Giacheti","doi":"10.28927/sr.2023.013022","DOIUrl":"https://doi.org/10.28927/sr.2023.013022","url":null,"abstract":"The mechanical behavior of municipal solid waste (MSW) is a critical issue in environmental geotechnics, given the pollution and public health risks associated with slope failures. In Brazil, waste composition is expected to change due to the hierarchy of sustainable practices established by the National Solid Waste Policy, which aims to improve the recovery of organic and recyclable materials. Not much progress has been made since the implementation of this law; thus, its effects on the design and operation of landfills are not fully clear. This study presents and discusses compaction and shear strength parameters of dry MSW after mechanical sorting of medium and large recyclable items and shredding. The maximum dry unit weight for the standard Proctor compaction test ranged from 6.6 to 10.0 kN/m3 and the optimum moisture content ranged from 20% to 42%. Stress-displacement curves of direct shear tests showed strain hardening and shear strength parameters of Mohr-Coulomb envelopes were displacement-dependent. The friction angle ranged from 3.2° to 42.9° and the cohesion intercept ranged from 1.3 to 31.3 kPa, at a displacement of 9 mm (15% of the specimen length). These results are in line with the literature, since a high content of waste materials that proved to affect geotechnical properties, such as plastic, paper, cardboard, textile, and glass, remained after pre-treatment.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45828524","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}
Fernanda Gomes, M. Motta, G. Bernardes, Paulo Soares
This study aimed to evaluate the influence of the addition of coconut (coir) fibers on the microstructural, hydraulic and mechanical behavior of an unsaturated compacted soil. Specimens were molded and compacted, forming composites with 0%, 0.1%, 0.5% and 1% fiber in relation to their dry mass. The characterization of pores from the soil and fiber soil mixtures was performed by the Mercury Intrusion Porosimetry tests. Suction values were obtained through the filter paper method and soil water retention curves were adjusted with the Durner model due to the bimodal behavior. Tensile strength values were obtained from the indirect tensile strength test (Brazilian tensile test) for specimens with different suction values. It was found that the increase in fiber content in the material lead to a non-linear increase in macropores, which affected both the hydraulic and mechanical behavior of the soil. Furthermore, the shape of the soil water retention curve was preserved, but there were changes in the values of first and second air entry and residual suction. The tensile strength was negatively influenced, reaching a reduction of about 30% in the situation with higher fiber content. However, for higher levels, the behavior of the soil changed from brittle to ductile, increasing the supported deformations.
{"title":"Influence of coconut fiber on the microstructural, mechanical and hydraulic behavior of unsaturated compacted soil","authors":"Fernanda Gomes, M. Motta, G. Bernardes, Paulo Soares","doi":"10.28927/sr.2023.013322","DOIUrl":"https://doi.org/10.28927/sr.2023.013322","url":null,"abstract":"This study aimed to evaluate the influence of the addition of coconut (coir) fibers on the microstructural, hydraulic and mechanical behavior of an unsaturated compacted soil. Specimens were molded and compacted, forming composites with 0%, 0.1%, 0.5% and 1% fiber in relation to their dry mass. The characterization of pores from the soil and fiber soil mixtures was performed by the Mercury Intrusion Porosimetry tests. Suction values were obtained through the filter paper method and soil water retention curves were adjusted with the Durner model due to the bimodal behavior. Tensile strength values were obtained from the indirect tensile strength test (Brazilian tensile test) for specimens with different suction values. It was found that the increase in fiber content in the material lead to a non-linear increase in macropores, which affected both the hydraulic and mechanical behavior of the soil. Furthermore, the shape of the soil water retention curve was preserved, but there were changes in the values of first and second air entry and residual suction. The tensile strength was negatively influenced, reaching a reduction of about 30% in the situation with higher fiber content. However, for higher levels, the behavior of the soil changed from brittle to ductile, increasing the supported deformations.","PeriodicalId":43687,"journal":{"name":"Soils and Rocks","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42517048","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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