Desiccation-induced cracks in reactive soils reduce their mechanical strength and increase their hydraulic conductivity (k). Polymer additives have demonstrated efficacy in improving resistance of clay against desiccation cracking and retaining low k when exposed to saline solutions. However, the risk of polymer elution from treated mixtures and its effect on the durability of gains have received little attention. This study evaluated polymer leaching during consolidation and permeation in reconstituted mixtures. Sodium carboxymethyl cellulose (Na-CMC) was added to Na-bentonite via wet mixing (WM) and dry mixing (DM). Conducting a series of k tests on amended and unamended samples, polymer retention and elution were assessed using thermogravimetric (TGA) and total organic carbon (TOC) analyses. Na-CMC incorporation under DM reduced k by approximately 60%. DM exhibited higher levels of polymer leaching compared to WM, increasing permeability over time. Nevertheless, despite polymer loss, k values for both DM and WM specimens remained lower than untreated bentonite for up to 100 days of permeation. Furthermore, introducing a slit-film geotextile as a potential remedy for leaching did not significantly enhance polymer retention in DM samples. However, it reduced the polymer content in the effluent, suggesting that the geotextile, not the bentonite, could have retained the polymer.
反应性土壤中因干燥而产生的裂缝会降低其机械强度，并增加其导水率（k）。聚合物添加剂在提高粘土的抗干燥开裂能力以及在暴露于盐溶液时保持低 k 值方面具有显著效果。然而，聚合物从处理过的混合物中洗脱的风险及其对增益耐久性的影响却很少受到关注。本研究评估了聚合物在重组混合物的固结和渗透过程中的浸出情况。通过湿法混合（WM）和干法混合（DM）将羧甲基纤维素钠（Na-CMC）加入 Na-膨润土中。利用热重（TGA）和总有机碳（TOC）分析法，对添加过和未添加过的样品进行了一系列 k 试验，以评估聚合物的保留和洗脱情况。在 DM 中加入 Na-CMC 可使 k 值降低约 60%。与 WM 相比，DM 表现出更高的聚合物浸出水平，随着时间的推移增加了渗透性。不过，尽管聚合物流失，但在长达 100 天的渗透过程中，DM 和 WM 试样的 k 值仍然低于未处理的膨润土。此外，在 DM 样品中引入缝隙薄膜土工织物作为沥滤的潜在补救措施，并不能显著提高聚合物的保留率。然而，它却降低了流出物中的聚合物含量，这表明可能是土工织物而不是膨润土保留了聚合物。
{"title":"Na-CMC-amended clay: effect of mixing method on hydraulic conductivity and polymer elution","authors":"S. Taheri, A. El-Zein, B. Yu","doi":"10.1680/jgein.23.00116","DOIUrl":"https://doi.org/10.1680/jgein.23.00116","url":null,"abstract":"Desiccation-induced cracks in reactive soils reduce their mechanical strength and increase their hydraulic conductivity (k). Polymer additives have demonstrated efficacy in improving resistance of clay against desiccation cracking and retaining low k when exposed to saline solutions. However, the risk of polymer elution from treated mixtures and its effect on the durability of gains have received little attention. This study evaluated polymer leaching during consolidation and permeation in reconstituted mixtures. Sodium carboxymethyl cellulose (Na-CMC) was added to Na-bentonite via wet mixing (WM) and dry mixing (DM). Conducting a series of k tests on amended and unamended samples, polymer retention and elution were assessed using thermogravimetric (TGA) and total organic carbon (TOC) analyses. Na-CMC incorporation under DM reduced k by approximately 60%. DM exhibited higher levels of polymer leaching compared to WM, increasing permeability over time. Nevertheless, despite polymer loss, k values for both DM and WM specimens remained lower than untreated bentonite for up to 100 days of permeation. Furthermore, introducing a slit-film geotextile as a potential remedy for leaching did not significantly enhance polymer retention in DM samples. However, it reduced the polymer content in the effluent, suggesting that the geotextile, not the bentonite, could have retained the polymer.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"113 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140630834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H.-J. Kim, P. R. Dinoy, H.-J. Kim, V. A. Corsino Jr, Y.-S. Joung, J.-Y. Park
A nonlinear model for consolidated geotextile-encased sand columns (GESACs) was formulated in this study. The model is based on the power law and predicts the stress-strain curve of a consolidated GESAC based on the superposition rule, wherein the stress-strain curve of the unconsolidated GESAC is superposed by the stress-strain curve of the soil alone in a consolidated triaxial test. A uniaxial compression test was conducted to study the failure mechanism of the GESAC. In addition, unconsolidated and consolidated triaxial tests on loose GESACs were conducted to investigate the effect of initial stresses on the shear behavior of GESACs. To further investigate the interaction between the soil and geotextile, and to assess the GESAC model, finite element method simulations were conducted. Based on the results, internal lateral stresses developed in the GESAC due to the confining effect of the geotextile, which increases the circumferential tension force on the geotextile while the p-q path of the GESAC approaches the critical state line, and follows the line when the shear strength of the soil is mobilized. The model was verified based on data on dense consolidated GESACs found in the literature, and results have shown good agreement between the measured and predicted data.
{"title":"A nonlinear analytical model for consolidated geotextile-encased sand columns","authors":"H.-J. Kim, P. R. Dinoy, H.-J. Kim, V. A. Corsino Jr, Y.-S. Joung, J.-Y. Park","doi":"10.1680/jgein.23.00092","DOIUrl":"https://doi.org/10.1680/jgein.23.00092","url":null,"abstract":"A nonlinear model for consolidated geotextile-encased sand columns (GESACs) was formulated in this study. The model is based on the power law and predicts the stress-strain curve of a consolidated GESAC based on the superposition rule, wherein the stress-strain curve of the unconsolidated GESAC is superposed by the stress-strain curve of the soil alone in a consolidated triaxial test. A uniaxial compression test was conducted to study the failure mechanism of the GESAC. In addition, unconsolidated and consolidated triaxial tests on loose GESACs were conducted to investigate the effect of initial stresses on the shear behavior of GESACs. To further investigate the interaction between the soil and geotextile, and to assess the GESAC model, finite element method simulations were conducted. Based on the results, internal lateral stresses developed in the GESAC due to the confining effect of the geotextile, which increases the circumferential tension force on the geotextile while the <i>p</i>-<i>q</i> path of the GESAC approaches the critical state line, and follows the line when the shear strength of the soil is mobilized. The model was verified based on data on dense consolidated GESACs found in the literature, and results have shown good agreement between the measured and predicted data.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"28 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140628174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geotextiles have been used as filters in geotechnical and geoenvironmental works for decades. Despite their broad utilization, these filters still find obstacles to the expansion of their application in larger projects and under complex soil and flow conditions. However, environmental issues are increasingly pressing for a greater use of geotextile filters in substitution to natural granular materials. Even though many important studies in the literature have improved the understanding of soil-fluid-geotextile filter interaction, some issues still require thorough investigation aiming at a better understanding on the behaviour of geotextile filters and the development of better design methodologies. This paper discusses how geotextiles filters are expected to behave in the field and some contradictions between idealized and real behaviour. Concerns regarding the use of geotextile filters under severe and critical conditions and how filter malfunction can be avoided or minimised are also addressed as well as approaches available to predict filter behaviour. A broad investigation on geotextile filter behaviour under severe and critical conditions was carried out and shows that these filters have been very successful, particularly bearing in mind the small number of failures in comparison with the huge number of applications of geotextile filters.
{"title":"Geotextile filters: from idealization to real behaviour (Giroud Lecture 2023)","authors":"E. M. Palmeira","doi":"10.1680/jgein.23.00160","DOIUrl":"https://doi.org/10.1680/jgein.23.00160","url":null,"abstract":"Geotextiles have been used as filters in geotechnical and geoenvironmental works for decades. Despite their broad utilization, these filters still find obstacles to the expansion of their application in larger projects and under complex soil and flow conditions. However, environmental issues are increasingly pressing for a greater use of geotextile filters in substitution to natural granular materials. Even though many important studies in the literature have improved the understanding of soil-fluid-geotextile filter interaction, some issues still require thorough investigation aiming at a better understanding on the behaviour of geotextile filters and the development of better design methodologies. This paper discusses how geotextiles filters are expected to behave in the field and some contradictions between idealized and real behaviour. Concerns regarding the use of geotextile filters under severe and critical conditions and how filter malfunction can be avoided or minimised are also addressed as well as approaches available to predict filter behaviour. A broad investigation on geotextile filter behaviour under severe and critical conditions was carried out and shows that these filters have been very successful, particularly bearing in mind the small number of failures in comparison with the huge number of applications of geotextile filters.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"20 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of recycled polyester (rPET) in construction materials offers significant benefits, including energy conservation, cost reduction, and decreased solid waste. This study compares the performance of rPET with that of virgin polyester (vPET) products. Therefore, two main testing programs including pull-out tests and creep performance tests were carried out in order to determine the interfacial properties of the geogrid-reinforced soil and time-dependent manner of the geogrids, respectively. Broadly speaking, this study showed that the performance of “rPET” geogrid is comparable with “vPET” geogrids. Pull-out tests revealed that pull-out resistance of both “vPET” and “rPET” geogrids were roughly the same and the “vPET” geogrid mostly had lower dilation angles in comparison with “rPET”. Moreover, based on the performance creep tests, it was understood that the long-term mechanical behaviour of “rPET” does not differ from the long-term behaviour of “vPET” products.
{"title":"Mechanical characteristics of geogrids produced from recycled polyester","authors":"G. T. Mehrjardi, R. Fuentes, O. Detert","doi":"10.1680/jgein.23.00062","DOIUrl":"https://doi.org/10.1680/jgein.23.00062","url":null,"abstract":"The use of recycled polyester (rPET) in construction materials offers significant benefits, including energy conservation, cost reduction, and decreased solid waste. This study compares the performance of rPET with that of virgin polyester (vPET) products. Therefore, two main testing programs including pull-out tests and creep performance tests were carried out in order to determine the interfacial properties of the geogrid-reinforced soil and time-dependent manner of the geogrids, respectively. Broadly speaking, this study showed that the performance of “rPET” geogrid is comparable with “vPET” geogrids. Pull-out tests revealed that pull-out resistance of both “vPET” and “rPET” geogrids were roughly the same and the “vPET” geogrid mostly had lower dilation angles in comparison with “rPET”. Moreover, based on the performance creep tests, it was understood that the long-term mechanical behaviour of “rPET” does not differ from the long-term behaviour of “vPET” products.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"44 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Liu, R. Zhang, J. Cheng, X. Geng, J. Zheng, K. Cheng
Horizontal drains are gradually introduced to the vacuum preloading method to improve dredged slurries by adding geotextiles to alleviate the blockage in the consolidation process. This study considers the consolidation of slurries enhanced by the vacuum preloading method with geotextile combined horizontal drains based on a double-layered consolidation model. The model approximates geotextile as a special soil layer possessing an equivalent consolidation factor. An analytical solution of the layered consolidation model is obtained using the Laplace transform and the finite Fourier transform method. The effectiveness of the solution is verified by comparing it with the one-dimensional double-layered consolidation solution and the one-dimensional consolidation with a partially permeable boundary. Through comparison with laboratory experiments, the model shows good fitness with the test results in the literature. The influences of related parameters, including the drain arrangement densities, soil parameters, and geotextile parameters, are discussed on average consolidation degree and pore water pressure. The influence mechanism is explained regarding drainage path and vacuum pressure transfer. Findings demonstrate that geotextile facilitates vacuum transfer and promotes soil consolidation, especially when the smaller density of drains’ deposition and lower soil permeability are applied.
{"title":"Analytical model for geotextile-enhanced horizontal drain vacuum consolidation of slurries","authors":"S. Liu, R. Zhang, J. Cheng, X. Geng, J. Zheng, K. Cheng","doi":"10.1680/jgein.23.00148","DOIUrl":"https://doi.org/10.1680/jgein.23.00148","url":null,"abstract":"Horizontal drains are gradually introduced to the vacuum preloading method to improve dredged slurries by adding geotextiles to alleviate the blockage in the consolidation process. This study considers the consolidation of slurries enhanced by the vacuum preloading method with geotextile combined horizontal drains based on a double-layered consolidation model. The model approximates geotextile as a special soil layer possessing an equivalent consolidation factor. An analytical solution of the layered consolidation model is obtained using the Laplace transform and the finite Fourier transform method. The effectiveness of the solution is verified by comparing it with the one-dimensional double-layered consolidation solution and the one-dimensional consolidation with a partially permeable boundary. Through comparison with laboratory experiments, the model shows good fitness with the test results in the literature. The influences of related parameters, including the drain arrangement densities, soil parameters, and geotextile parameters, are discussed on average consolidation degree and pore water pressure. The influence mechanism is explained regarding drainage path and vacuum pressure transfer. Findings demonstrate that geotextile facilitates vacuum transfer and promotes soil consolidation, especially when the smaller density of drains’ deposition and lower soil permeability are applied.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"41 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. L. E. Dias Filho, J. L. Silva, C. A. Valentin, M. P. Fleury, M. A. Aparicio-Ardila, D. M. Vidal, C. M. L. Costa
Humidity, air temperature, rainfall and solar radiation all contribute to the weathering of geosynthetics. Over time, the useful life can be affected and changes in properties can be observed, which affects the performance of these materials. As geosynthetics durability analyses must encompass each work condition, assessing the climate effects is essential for design purposes. This study exposed a nonwoven needle-punched poly(ethylene) terephthalate geotextile to natural weathering in three Brazilian cities (different exogenous environments) for 18 months. Mechanical tests were conducted to evaluate the geotextile changes due to weathering. This was demonstrated by the results: exposure to weather leads to the deterioration of the geotextile mechanical properties and increased stiffness. After four months, the tensile strength fell by half, while the deformation needed more than twelve months to have this same reduction; ultraviolet radiation intensity was the most effective weathering condition in the field; humidity and rainfall can affect the stiffness of geotextiles; the impact of accumulated climate factors gradually showed a convergence in the response of geotextile to weathering. Thus, this work highlights the need to evaluate the climate conditions in each location to understand the material's behavior on the exposure time.
{"title":"Natural weathering effects of nonwoven geotextile exposed to different climate conditions","authors":"J. L. E. Dias Filho, J. L. Silva, C. A. Valentin, M. P. Fleury, M. A. Aparicio-Ardila, D. M. Vidal, C. M. L. Costa","doi":"10.1680/jgein.23.00156","DOIUrl":"https://doi.org/10.1680/jgein.23.00156","url":null,"abstract":"Humidity, air temperature, rainfall and solar radiation all contribute to the weathering of geosynthetics. Over time, the useful life can be affected and changes in properties can be observed, which affects the performance of these materials. As geosynthetics durability analyses must encompass each work condition, assessing the climate effects is essential for design purposes. This study exposed a nonwoven needle-punched poly(ethylene) terephthalate geotextile to natural weathering in three Brazilian cities (different exogenous environments) for 18 months. Mechanical tests were conducted to evaluate the geotextile changes due to weathering. This was demonstrated by the results: exposure to weather leads to the deterioration of the geotextile mechanical properties and increased stiffness. After four months, the tensile strength fell by half, while the deformation needed more than twelve months to have this same reduction; ultraviolet radiation intensity was the most effective weathering condition in the field; humidity and rainfall can affect the stiffness of geotextiles; the impact of accumulated climate factors gradually showed a convergence in the response of geotextile to weathering. Thus, this work highlights the need to evaluate the climate conditions in each location to understand the material's behavior on the exposure time.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"144 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. H. Fan, R. Kerry Rowe, R. W. I. Brachman, J. Van Gulck
To quantify the effects of differential settlement on leakage through a geomembrane (GMB) hole in waste (landfill/mine tailings) covers, field experiments were conducted at Queen's University Experimental Liner Test Site on two sections, each with a 4H : 1V slope. Over 13 months, measurements showed that a 3 m × 2 m × 0.12–0.17 m depression in Section B led to a 51-fold increase in leakage when compared to Section A, which had no such depression (493 l vs 11.1 l). Notably, in Section B, 284 mm of precipitation between November and February resulted in 281 l of leakage, whereas 537 mm of precipitation between June and September led to a mere 142 l of leakage. A 3D numerical investigation provides encouraging agreement with the experimental measurements and confirms a counterintuitive 43% increase in leakage with a decrease in the temperature of cover sand from 21.9°C to 1°C, due to the influence of temperature-dependent viscosity on the hydraulic conductivity of the cover soil. This paper offers insights for optimizing waste cover design and inspection procedures to mitigate the challenges of contaminant control.
为了量化差异沉降对通过废物（垃圾填埋场/矿山尾矿）覆盖层中的土工膜（GMB）孔渗漏的影响，在皇后大学实验衬垫试验场进行了两段实地实验，每段的坡度为 4H ：1V 的坡度。13 个月的测量结果表明，与没有凹陷的 A 区相比，B 区 3 m × 2 m × 0.12-0.17 m 的凹陷导致渗漏量增加了 51 倍（493 升比 11.1 升）。值得注意的是，在 B 区段，11 月至次年 2 月间 284 毫米的降水量导致 281 升的渗漏，而 6 月至 9 月间 537 毫米的降水量仅导致 142 升的渗漏。三维数值研究与实验测量结果的一致性令人鼓舞，并且证实，随着覆盖砂的温度从 21.9°C 降至 1°C，渗漏量增加了 43%，这是由于温度相关粘度对覆盖土导流性的影响。本文为优化废物覆盖设计和检查程序以减轻污染物控制挑战提供了启示。
{"title":"Impact of differential settlement on leakage through geomembranes in waste covers","authors":"Y. H. Fan, R. Kerry Rowe, R. W. I. Brachman, J. Van Gulck","doi":"10.1680/jgein.23.00175","DOIUrl":"https://doi.org/10.1680/jgein.23.00175","url":null,"abstract":"To quantify the effects of differential settlement on leakage through a geomembrane (GMB) hole in waste (landfill/mine tailings) covers, field experiments were conducted at Queen's University Experimental Liner Test Site on two sections, each with a 4H : 1V slope. Over 13 months, measurements showed that a 3 m × 2 m × 0.12–0.17 m depression in Section B led to a 51-fold increase in leakage when compared to Section A, which had no such depression (493 l vs 11.1 l). Notably, in Section B, 284 mm of precipitation between November and February resulted in 281 l of leakage, whereas 537 mm of precipitation between June and September led to a mere 142 l of leakage. A 3D numerical investigation provides encouraging agreement with the experimental measurements and confirms a counterintuitive 43% increase in leakage with a decrease in the temperature of cover sand from 21.9°C to 1°C, due to the influence of temperature-dependent viscosity on the hydraulic conductivity of the cover soil. This paper offers insights for optimizing waste cover design and inspection procedures to mitigate the challenges of contaminant control.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"180 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of geogrid reinforcement has proven to be an effective measure to improve the anchor uplift capacity. However, previous studies are limited to analyzing the axial pullout capacity of plate anchors. In comparison, the anchor foundations employed in field are compelled to resist both uplift and lateral forces. In most cases, the foundation's safety against lateral forces dictates the design criteria for tall structures. Therefore, improving the foundation's lateral load-bearing capacity is of utmost importance. This paper presents a three-dimensional numerical analysis of anchor foundations in geogrid-reinforced sand under uplift and lateral forces. The results highlight the benefits of geogrid reinforcement on the anchor's response to uplift and lateral loads. The geogrid reinforcement is modelled using cable elements capturing the actual apertures responsible for tensile force mobilization along the geogrid ribs. A significant reduction in the displacements of the anchor foundation is observed in geogrid-reinforced sand, both in horizontal and vertical directions, when combined loads are applied on the anchor. However, the maximum reduction is found in the case of vertical uplift forces for higher values of the applied load. The practical implication of this study is demonstrated using a performance-based design example of transmission tower foundations in geogrid-reinforced sand.
{"title":"Response of anchor foundations in geogrid reinforced sand under combined loads","authors":"S. Mukherjee, G. L. Sivakumar Babu","doi":"10.1680/jgein.23.00119","DOIUrl":"https://doi.org/10.1680/jgein.23.00119","url":null,"abstract":"The use of geogrid reinforcement has proven to be an effective measure to improve the anchor uplift capacity. However, previous studies are limited to analyzing the axial pullout capacity of plate anchors. In comparison, the anchor foundations employed in field are compelled to resist both uplift and lateral forces. In most cases, the foundation's safety against lateral forces dictates the design criteria for tall structures. Therefore, improving the foundation's lateral load-bearing capacity is of utmost importance. This paper presents a three-dimensional numerical analysis of anchor foundations in geogrid-reinforced sand under uplift and lateral forces. The results highlight the benefits of geogrid reinforcement on the anchor's response to uplift and lateral loads. The geogrid reinforcement is modelled using cable elements capturing the actual apertures responsible for tensile force mobilization along the geogrid ribs. A significant reduction in the displacements of the anchor foundation is observed in geogrid-reinforced sand, both in horizontal and vertical directions, when combined loads are applied on the anchor. However, the maximum reduction is found in the case of vertical uplift forces for higher values of the applied load. The practical implication of this study is demonstrated using a performance-based design example of transmission tower foundations in geogrid-reinforced sand.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"144 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Khorrami, M. M. Tochaee, M. Payan, R. Jamshidi Chenari
The compression behaviour of the mixture of glass beads (representing rigid particles) and EPS beads (representing deformable particles) during the loading-unloading process is systematically examined through performing two sets of large-size oedometer experiments, including incremental step-by-step and one-step loading scenarios. At each step during the loading-unloading cycle, the void ratio (e) and the at-rest coefficient of lateral earth pressure (K0) are measured for pure rigid samples and rigid-soft particle mixtures. To consider the creep effect, the overburden pressure at the final loading step is maintained on the sample for 24 hours prior to unloading. The results show that at a given overburden pressure, with the addition of soft particles to the pure rigid aggregates, the values of e and K0 decrease. Additionally, for both pure rigid samples and rigid-soft particle mixtures, with increasing the overburden pressure, e decreases whereas K0 augments. Moreover, due to the creep behaviour during the constant loading step, K0 decreases over time for both samples; the phenomenon which is observed to be more pronounced for pure rigid aggregates compared to rigid-soft particle mixtures. Finally, a well-established creep model is used to simulate the creep behaviour of pure rigid samples and rigid-soft particle composites.
{"title":"Deformation characteristics and creep behaviour of rigid particulates-EPS beads composites","authors":"R. Khorrami, M. M. Tochaee, M. Payan, R. Jamshidi Chenari","doi":"10.1680/jgein.23.00145","DOIUrl":"https://doi.org/10.1680/jgein.23.00145","url":null,"abstract":"The compression behaviour of the mixture of glass beads (representing rigid particles) and EPS beads (representing deformable particles) during the loading-unloading process is systematically examined through performing two sets of large-size oedometer experiments, including incremental step-by-step and one-step loading scenarios. At each step during the loading-unloading cycle, the void ratio (<i>e</i>) and the at-rest coefficient of lateral earth pressure (<i>K</i><sub>0</sub>) are measured for pure rigid samples and rigid-soft particle mixtures. To consider the creep effect, the overburden pressure at the final loading step is maintained on the sample for 24 hours prior to unloading. The results show that at a given overburden pressure, with the addition of soft particles to the pure rigid aggregates, the values of <i>e</i> and <i>K</i><sub>0</sub> decrease. Additionally, for both pure rigid samples and rigid-soft particle mixtures, with increasing the overburden pressure, <i>e</i> decreases whereas <i>K</i><sub>0</sub> augments. Moreover, due to the creep behaviour during the constant loading step, <i>K</i><sub>0</sub> decreases over time for both samples; the phenomenon which is observed to be more pronounced for pure rigid aggregates compared to rigid-soft particle mixtures. Finally, a well-established creep model is used to simulate the creep behaviour of pure rigid samples and rigid-soft particle composites.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"307 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. C. Qiu, G. Z. Xu, G. Q. Gu, W. Z. Song, D. H. Cao
This study investigated the performance of unreinforced and geogrid-encased cement-stabilized dredged slurry columns by uniaxial compression tests to simulate the extreme case where the surrounding soil offers no confinement. The objective was to understand the strength characteristics and visualize the deformation damage patterns of the columns with respect to the water content, cement content, length-to-diameter ratio, and geogrid strength. The results show that the unreinforced specimens exhibited strain-softening behavior, whereas geogrid encasement induced strain-hardening, with high-strength geogrids showing superior strain-hardening capacity. Notably, regardless of geogrid strength, encasement enhanced the resistance to deformation and ductility of the columns. Increasing the cement content, reducing the water content, and decreasing the length-to-diameter ratio all contributed to higher peak strength in both unreinforced and geogrid-encased specimens. Geogrid encasement provides confinement that enhances peak strength. The influence of geogrid encasement on peak strength becomes more pronounced at lower cement contents, higher water contents, and higher length-to-diameter ratios. Geogrid encasement also affects failure modes, altering the predominant inclined shear failure observed at the top of unreinforced specimens. Specimens encased with geogrids of higher tensile strength exhibit enhanced integrity and deformation resembling compression strut buckling, with a symmetrically inclined failure trend at the top and bottom.
{"title":"Uniaxial compression test of cement-solidified dredged slurry columns encased with geogrid","authors":"C. C. Qiu, G. Z. Xu, G. Q. Gu, W. Z. Song, D. H. Cao","doi":"10.1680/jgein.23.00132","DOIUrl":"https://doi.org/10.1680/jgein.23.00132","url":null,"abstract":"This study investigated the performance of unreinforced and geogrid-encased cement-stabilized dredged slurry columns by uniaxial compression tests to simulate the extreme case where the surrounding soil offers no confinement. The objective was to understand the strength characteristics and visualize the deformation damage patterns of the columns with respect to the water content, cement content, length-to-diameter ratio, and geogrid strength. The results show that the unreinforced specimens exhibited strain-softening behavior, whereas geogrid encasement induced strain-hardening, with high-strength geogrids showing superior strain-hardening capacity. Notably, regardless of geogrid strength, encasement enhanced the resistance to deformation and ductility of the columns. Increasing the cement content, reducing the water content, and decreasing the length-to-diameter ratio all contributed to higher peak strength in both unreinforced and geogrid-encased specimens. Geogrid encasement provides confinement that enhances peak strength. The influence of geogrid encasement on peak strength becomes more pronounced at lower cement contents, higher water contents, and higher length-to-diameter ratios. Geogrid encasement also affects failure modes, altering the predominant inclined shear failure observed at the top of unreinforced specimens. Specimens encased with geogrids of higher tensile strength exhibit enhanced integrity and deformation resembling compression strut buckling, with a symmetrically inclined failure trend at the top and bottom.","PeriodicalId":12616,"journal":{"name":"Geosynthetics International","volume":"144 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140199032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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