Editorial

3 pages, 173 KiB

Open AccessEditorial

Recent Advancements in Geosynthetic Engineering for Sustainable Construction

by Wei Guo and Thanh T. Nguyen

Sustainability 2023, 15(15), 11884; https://doi.org/10.3390/su151511884 - 02 Aug 2023

Cited by 1 | Viewed by 827

Sustainable construction has become increasingly crucial recently due to the massive negative impacts that construction, including various geotechnical activities, can have on the surrounding environment [...] Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

Research

Jump to: Editorial, Review

16 pages, 3647 KiB

Open AccessArticle

Experimental Investigations on the Tensile Mechanical Behavior of HDPE Geocell Strip

by Zheng Zuo, Xiuqiang Hao, Huiqiang Li, Wei Wang, Guangqing Yang and Ying Liu

Sustainability 2023, 15(10), 7820; https://doi.org/10.3390/su15107820 - 10 May 2023

Cited by 4 | Viewed by 1109

Abstract

Geocells are commonly adopted in various engineering constructions, such as railways and ports. Currently, the reinforcement effects and mechanisms of geocells in engineering is being widely studied, while limited studies have been performed on the mechanical behavior of geocell strips. Uncertainties regarding their [...] Read more.

Geocells are commonly adopted in various engineering constructions, such as railways and ports. Currently, the reinforcement effects and mechanisms of geocells in engineering is being widely studied, while limited studies have been performed on the mechanical behavior of geocell strips. Uncertainties regarding their performance have impeded the wide application of geocells in engineering fields. In this paper, a series of tensile tests and trapezoidal tests were performed on high-density polyethylene (HDPE) geocell strips. The effects regarding specimen shape, specimen width, and welding junction on the tensile mechanical behavior of HDPE geocell strips were investigated. Additionally, the results of the tensile test and trapezoidal test were also compared. The test results showed that the tensile strength of a HDPE geocell strip was less affected by the specimen shape and specimen width, within 5%. However, the elongation of HDPE strips was sensitive to the specimen shape, and the difference between type I dumbbell and type II rectangular was up to 38%. The effect of the welding junction on the HDPE strip cannot be ignored, the strength retention rate of the welding junction was 76.3%. The curve of the trapezoidal test was similar to that of the tensile test, and the force of trapezoidal test was 0.87 times that of the tensile test. The test results can provide a reference for the testing of strip performance and structural design. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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20 pages, 6604 KiB

Open AccessArticle

Experimental Study of Improvement in Tensile Property of Geosynthetics under Confinement

by Dan Li, Yihuai Liang, Di Wu, Chen Luo, Yanxin Yang, Yang Yi and Jianjian Wu

Sustainability 2023, 15(9), 7376; https://doi.org/10.3390/su15097376 - 28 Apr 2023

Cited by 1 | Viewed by 852

Abstract

A new in-soil tensile test apparatus was developed to simulate the in-soil stress condition of geosynthetics in a real working state. An in-soil tensile test with or without friction was conducted, along with in-air tensile tests of eight types of geosynthetics, to evaluate [...] Read more.

A new in-soil tensile test apparatus was developed to simulate the in-soil stress condition of geosynthetics in a real working state. An in-soil tensile test with or without friction was conducted, along with in-air tensile tests of eight types of geosynthetics, to evaluate tensile properties, including tensile load and secant tensile stiffness under different confining stresses using various methods. Under confinement, the tensile properties of geosynthetics increased with growing confinement, which were greater than those for the in-air tensile test, and the tensile properties were similar for tests with or without friction. The tensile load improvement factors F_T_−σ and f_T_−σ were introduced to quantify the confinement and reinforcement–soil friction differences between different tests, and the improvement ratios γ₁ and γ₂ were proposed to quantify the improvement of tensile load under confinement for the test with and without friction, respectively. Two formulas were proposed to predict the confined tensile properties of geosynthetics. The results showed that confinement was the major factor that improved the tensile properties of geosynthetics compared to reinforcement–soil friction. When the improvement ratio is not less than 1.5, the confined tensile load should replace the in-air tensile load with the tensile strength design of geosynthetics, which provides an insight into the design of reinforced soil structures. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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18 pages, 6837 KiB

Open AccessArticle

Study on Bearing Capacity and Failure Mode of Multi-Layer-Encased Geosynthetic-Encased Stone Column under Dynamic and Static Loading

by Bowen Kang, Jiaquan Wang, Yuanwu Zhou and Shibin Huang

Sustainability 2023, 15(6), 5205; https://doi.org/10.3390/su15065205 - 15 Mar 2023

Cited by 5 | Viewed by 1370

Abstract

The “method of overlap” replaces traditional welding to solve the problem of how the geosynthetic-encased stone column is limited by the welding frame during site construction, making the site construction simplified and economical, but its bearing mechanism is not clear. Therefore, the bearing [...] Read more.

The “method of overlap” replaces traditional welding to solve the problem of how the geosynthetic-encased stone column is limited by the welding frame during site construction, making the site construction simplified and economical, but its bearing mechanism is not clear. Therefore, the bearing mechanism and failure mode of the stone column was studied through the compression test of the multi-layer geosynthetic-encased stone column under dynamic and static loading. The research shows that the multi-layer encasement improves the modulus and lateral restraint of the stone column, which increases the stress transfer rate and reduces the damage degree of the stone column. The vertical ultimate bearing capacity increase in multi-layer geosynthetic-encased stone columns under dynamic and static loading is significantly different, and the difference can be up to 47.1%; the corresponding number of encasement layers should be selected according to the actual situation. The influence of the difference between dynamic and static loading on the location of the main radial strain of the stone column can be ignored, but the lateral restraint of the stone column under dynamic loading is weakened, the stress transfer rate is reduced, and the radial strain is reduced and more uniform along the stone column height. The vertical ultimate bearing capacity of the one- and two-layer geogrid-encased stone column under dynamic loading is lower than that of static loading. When treating soft foundations, the influence of traffic loads should be considered, and the bearing capacity of the geosynthetic-encased stone column should be appropriately increased in design value. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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16 pages, 8091 KiB

Open AccessArticle

Performances of the Soil–Bentonite Cutoff Wall Composited with Geosynthetic Clay Liners: Large-Scale Model Tests and Numerical Simulations

by Liang-Tong Zhan, Lin-Feng Cao, Rui Zhao, Zhao-Hua Ding, Shi-Ping Xie and Yun-Min Chen

Sustainability 2023, 15(3), 1886; https://doi.org/10.3390/su15031886 - 18 Jan 2023

Cited by 4 | Viewed by 1260

Abstract

The geosynthetic clay liner (GCL) overlap plays a key role in maintaining hydraulic performance of the barrier systems, e.g., the bottom liner and cover systems. However, its influences on the behavior of the vertical barrier have been rarely investigated. This paper aims to [...] Read more.

The geosynthetic clay liner (GCL) overlap plays a key role in maintaining hydraulic performance of the barrier systems, e.g., the bottom liner and cover systems. However, its influences on the behavior of the vertical barrier have been rarely investigated. This paper aims to address this issue using the large-scale model test and 3-dimensional finite element (FE) modeling. In the model test, the GCL overlap at the width of 500 mm was tested under a constant hydraulic head of 1 m and confining stress ranging from 10 to 150 kPa using a newly developed large-scale apparatus. Compared with the flexible wall permeameter, this apparatus could guarantee full field-scale GCL overlap to be tested. Results showed that the effective hydraulic conductivity of the GCL overlap decreased from 10⁻⁸ to 10⁻⁹ cm/s as the confining stress increased from 10 to 150 kPa. The addition of supplemental bentonite paste in between the overlap with a water-to-bentonite ratio of 19:1 contributed to reducing the effective hydraulic conductivity by 60% compared with that for a GCL overlap without bentonite paste. The breakthrough time for the soil-bentonite (SB) cutoff wall composited with GCLs was 64% longer in comparison with that for the single SB wall. Additionally, the breakthrough after 50 years is made for the entire depth of the single SB wall while at the depth no more than 0.9 m for the composite wall with bentonite paste at the GCL overlap. With consideration that the depth of the groundwater table is generally greater than 1 m, the GCL–SB composite cutoff wall will exhibit a good performance in containing groundwater contaminants in the field, especially when applying bentonite paste at the GCL overlap. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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15 pages, 3316 KiB

Open AccessArticle

Analysis of Dynamic Deformation Response of Closely Spaced Square Footings on Geogrid-Reinforced Sand under Cyclic Loading

by Jiaquan Wang, Hangxiang Qi, Zhinan Lin and Yi Tang

Sustainability 2023, 15(1), 438; https://doi.org/10.3390/su15010438 - 27 Dec 2022

Cited by 2 | Viewed by 1217

Abstract

In order to obtain the optimal spacing of closely spaced footings under cyclic dynamic loading, dynamic model tests of closely spaced footings were carried out on unreinforced and reinforced sand foundations. The influence of the center point spacing (S) of closely [...] Read more.

In order to obtain the optimal spacing of closely spaced footings under cyclic dynamic loading, dynamic model tests of closely spaced footings were carried out on unreinforced and reinforced sand foundations. The influence of the center point spacing (S) of closely spaced footings on the bearing capacity of the foundation under cyclic dynamic load is discussed. The test results show the following: (1) The dynamic load peak of the unreinforced and reinforced sand foundation is the largest when S/B = 2.0 (B is the width of footing), and the ultimate bearing capacity of the reinforced sand foundation is 20% higher than that of unreinforced sand foundation. (2) The vertical soil pressure at different positions of closely spaced footings with different spacing ratios (S/B) on the reinforced sand foundation is lower than that of unreinforced sand foundation, and the vertical soil pressure at different buried depths (‘1-3’, ‘2-3’, ‘3-3’ positions) at the center of closely spaced footings are smaller than that below the footings (‘1-2’, ‘2-2’, ‘3-2’ positions). (3) When S/B = 2.0, the strain of geogrid and the peak acceleration at the center of the closely spaced footings are the smallest, indicating that the sand foundation has little transient change under this spacing. From the aspects of ultimate bearing capacity design and engineering economic benefits, it is suggested that the spacing between closely spaced footings should be arranged according to two times the width of the footing (S/B = 2.0). Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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14 pages, 4866 KiB

Open AccessArticle

Evaluation of the Laboratory Degradation Performance of a Straw Drainage Board

by Runtian Zhu, Yinqiang Su, Cankun Wu, Wei Yuan and Yongfeng Deng

Sustainability 2022, 14(24), 16365; https://doi.org/10.3390/su142416365 - 07 Dec 2022

Cited by 3 | Viewed by 1193

Abstract

Plastic drainage boards are installed into the foundation as vertical drainage channels in vacuum preloading projects. After construction, numerous plastic drainage boards are left in the foundation, causing not only white pollution but also potential groundwater contamination. Straw was utilized to produce degradable [...] Read more.

Plastic drainage boards are installed into the foundation as vertical drainage channels in vacuum preloading projects. After construction, numerous plastic drainage boards are left in the foundation, causing not only white pollution but also potential groundwater contamination. Straw was utilized to produce degradable drainage boards in this study, and the feasibility of straw drainage boards was confirmed by laboratory degradation tests. The results revealed that Zhuhai’s soft marine soil is rich in degrading bacteria such as Bacteroidota and Firmicutes, which have adverse effects on the performance of the straw drainage board. The straw drainage board was deteriorated by bacteria in the foundation, and the discharge capacity and tensile strength dropped with time, with the discharge capacity degradation relationship as q_w(t) = q_w₀(1 − 3.83 × 10⁻⁶t²). The discharge capacity and tensile strength of straw drainage boards are lower than those of plastic drainage boards, but they all meet the engineering requirements. Straw drainage boards can replace plastic drainage boards in vacuum preloading reinforcement projects, which not only solves the problem of environmental pollution but also expands the comprehensive utilization of straw resources in a new way. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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16 pages, 12000 KiB

Open AccessArticle

Dynamic Characteristics of Reinforced Soil Retaining Wall with Composite Gabion Based on Time Domain Identification Method

by Xiaoguang Cai, Shaoqiu Zhang, Sihan Li, Honglu Xu, Xin Huang, Chen Zhu and Xin Liu

Sustainability 2022, 14(23), 16321; https://doi.org/10.3390/su142316321 - 06 Dec 2022

Cited by 1 | Viewed by 1457

Abstract

A series of shaking table tests was carried out on the dynamic performance and working mechanism of a gabion reinforced soil retaining wall under seismic load. The test results show that the panel presents the deformation mode of middle and upper bulging at [...] Read more.

A series of shaking table tests was carried out on the dynamic performance and working mechanism of a gabion reinforced soil retaining wall under seismic load. The test results show that the panel presents the deformation mode of middle and upper bulging at the contact point between the rigid box and the retaining wall The settlement of top backfill is relatively uniform, and there is basically no differential settlement, the natural frequencies at different positions and heights inside the retaining wall are basically the same, and the natural frequencies are stable between 22.61 and 23.04 Hz below 0.8 g. The damping ratio decreases with the increase in wall height, and the damping ratio at each stage after vibration is greater than that before vibration. The seismic earth pressure is nonlinearly distributed. The measured value of the lower part of the retaining wall is smaller than that calculated by the Seed–Whitman method with an increase in peak acceleration, and the measured value of the upper part of the retaining wall is larger than the theoretical calculation results. The position of the resultant action point of seismic earth pressure is greater than 0.33 times the wall height specified by the Mononobe–Okabe method. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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17 pages, 5948 KiB

Open AccessArticle

Model Test and Numerical Simulation Research of Reinforced Soil Retaining Walls under Cyclic Loads

by He Wang, Nan Wang, Guangqing Yang and Jian Ma

Sustainability 2022, 14(23), 15643; https://doi.org/10.3390/su142315643 - 24 Nov 2022

Cited by 1 | Viewed by 1237

Abstract

The stress diffusion characteristics of reinforced soil retaining walls (RSW) with concrete-block panels under cyclic loads are studied. The distribution of the vertical dynamic earth pressure caused by an external load and the analysis of stress diffusion angles were studied using a model [...] Read more.

The stress diffusion characteristics of reinforced soil retaining walls (RSW) with concrete-block panels under cyclic loads are studied. The distribution of the vertical dynamic earth pressure caused by an external load and the analysis of stress diffusion angles were studied using a model test and the numerical simulation model of the reinforced soil retaining wall was established to analyze the change in the stress diffusion angle. We then changed the parameters to investigate the influencing factors of the stress diffusion characteristics. The results showed that: the average value of the peak vertical dynamic earth pressure caused by an external load at the loading position of the RSW was a nonlinear distribution, decaying from top to bottom and increasing with the increase in the loading amplitude, while the change in the loading frequency number of loading cycles had no obvious rule. The results of model test and numerical simulation agree with each other. The diffusion angle of the stress caused by the external load of the reinforced body was basically between 50° and 65° in the range from 1.8 m to 1.2 m, the diffusion angle at the top was slightly larger than the middle, and the diffusion angle away from the wall was larger than the diffusion angle close to the wall. The main factors affecting the stress diffusion in reinforced soil retaining walls are the coefficient of reinforcement of the soil and the dynamic stress amplitude; the stress diffusion angle increased with an increase in the coefficient of the reinforcement of the soil and the dynamic stress amplitude. The conclusion of this paper can provide a reference for the design of reinforced soil structures. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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15 pages, 6038 KiB

Open AccessArticle

Research on the Effect of Particle Size on the Interface Friction between Geogrid Reinforcement and Soil

by Yunfei Zhao, Guangqing Yang, Zhi Wang and Shaopeng Yuan

Sustainability 2022, 14(22), 15443; https://doi.org/10.3390/su142215443 - 21 Nov 2022

Cited by 4 | Viewed by 1177

Abstract

For projects such as roads and railways, different fillers are often selected, and these also relate to the area where the project is located, so the characteristics of the filling soil should be considered in the design. However, the characteristics of the soil [...] Read more.

For projects such as roads and railways, different fillers are often selected, and these also relate to the area where the project is located, so the characteristics of the filling soil should be considered in the design. However, the characteristics of the soil used in geosynthetic-reinforced soil (GRS) structure design are routinely simple soil properties and are not based on testing of soil with reinforcement. In order to study the influence of fillers with different particle sizes on the interface friction characteristics between the geogrid and soil, a self-developed large-scale pull-out testing machine was used. Under the action of a normal static load, pull-out tests were carried out with different fillers, such as sand, silt and gravel. According to the test results, the greater the stress applied in the normal direction, the greater the maximum pull-out force. As for the different fillers, shear stress from material with a larger particle size, such as gravel, was larger than that of sand and silt. Finally, to reveal the pattern of how the soil particles moved during the pull-out test, from a microscopic point of view, and the effect on particle–mesh size ratio, a series of discrete element method (DEM) analyses were conducted by PFC^2D. The results indicated that a larger particle is more likely to rotate and move during the test, and this makes the interlocking effect greater between the geogrid and the soil, which leads to a larger pull-out force in the laboratory test. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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22 pages, 5970 KiB

Open AccessArticle

Analysis of the Working Response Mechanism of Wrapped Face Reinforced Soil Retaining Wall under Strong Vibration

by Honglu Xu, Xiaoguang Cai, Haiyun Wang, Sihan Li, Xin Huang and Shaoqiu Zhang

Sustainability 2022, 14(15), 9741; https://doi.org/10.3390/su14159741 - 08 Aug 2022

Cited by 5 | Viewed by 1354

Abstract

A series of shaking table tests were carried out to explore the dynamic characteristics and working mechanisms of wrapped-face reinforced soil-retaining walls under strong vibration. Under the 0.1–1.0 g horizontal peak ground acceleration (HPGA), the damping ratio of sand shows a downward trend [...] Read more.

A series of shaking table tests were carried out to explore the dynamic characteristics and working mechanisms of wrapped-face reinforced soil-retaining walls under strong vibration. Under the 0.1–1.0 g horizontal peak ground acceleration (HPGA), the damping ratio of sand shows a downward trend as a whole, so the acceleration amplification coefficient decreases with the increase of HPGA. However, when HPGA reaches 1.0 g, the acceleration amplification coefficient increases; the range of acceleration amplification coefficient at the top of the wall is 1.69–1.36. When HPGA is 1.0 g, the maximum cumulative residual displacement of the panel is 2.96% H, and the maximum uneven settlement of the sand is 3.57% H, both of which have exceeded the limit of the specification. With the increase of HPGA, the ratio of the dynamic earth force increment to the total dynamic earth force gradually approaches 50%. Since the reinforcement effect of geogrid is not considered, the predicted value of traditional earth pressure theory is different from the measured value. According to the Washington State Department of Transportation displacement index, the deformation range of wrapped-face reinforced soil-retaining walls is divided into three stages: the quasi-elastic stage, the plastic stage, and the failure stage. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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Review

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18 pages, 2828 KiB

Open AccessReview

Natural Fibre for Geotechnical Applications: Concepts, Achievements and Challenges

by Thanh T. Nguyen and Buddhima Indraratna

Sustainability 2023, 15(11), 8603; https://doi.org/10.3390/su15118603 - 25 May 2023

Cited by 5 | Viewed by 1870

Abstract

Enhancing the use of natural fibre for geotechnical purposes has attracted greater attention in the past decade, mainly because of the tangible benefits that this green approach would bring to our sustainable infrastructure developments. While this topic has been subjected to often sceptical [...] Read more.

Enhancing the use of natural fibre for geotechnical purposes has attracted greater attention in the past decade, mainly because of the tangible benefits that this green approach would bring to our sustainable infrastructure developments. While this topic has been subjected to often sceptical review or discussions, they usually focus on narrow aspects such as soil reinforcement, resulting in a lack of thorough assessment over different aspects and applications. The current paper hence aims to not only provide a more balanced review between theoretical concepts and practical perspectives, but also to link different functions of natural fibre that would facilitate design effectiveness. Three major geotechnical purposes of natural fibre in terms of the practice are identified and discussed, i.e., (i) soil reinforcement; (ii) enhanced drainage for soil consolidation; and (iii) filtration, separation and erosion controls. In these distinct applications, natural fibres, despite being used in different forms such as geotextiles, drains and individual fibres, often give significant contributions to improving soil structures, resulting in greater stabilization of the entire system. The key unique feature of natural fibres is their ability to generate biological bonding with soil media (i.e., biodegradation associated with reinforcement), while substantially improving the tensile strength of the soil structure, thus providing larger resistance to mud pumping, liquefaction, internal instability and erosion. Apart from successful findings and applications in practice, main challenges that are currently hampering the wider application of natural fibres will be addressed in this paper. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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15 pages, 5440 KiB

Open AccessReview

Recent Developments in the Vacuum Preloading Technique in China

by You Zhou, Shuli Chen, Wei Guo, Yuxiao Ren and Guizhong Xu

Sustainability 2022, 14(21), 13897; https://doi.org/10.3390/su142113897 - 26 Oct 2022

Cited by 11 | Viewed by 2120

Abstract

A series of studies have confirmed that vacuum preloading can effectively accelerate the consolidation process of soft soil. In recent years, further improvement in the efficiency of this method is still the continuing goal of scholars. This paper reviews the recent improvements in [...] Read more.

A series of studies have confirmed that vacuum preloading can effectively accelerate the consolidation process of soft soil. In recent years, further improvement in the efficiency of this method is still the continuing goal of scholars. This paper reviews the recent improvements in the vacuum preloading techniques as well as their practical applications in China. The advantages and disadvantages of each method are discussed. It is found that replacing or eliminating one or more components of the vacuum preloading system, such as sand-free, membrane-free, horizontal drain, multiple-step, and air booster vacuum preloading methods, achieved similar soil improvement effects to those of the traditional vacuum preloading method. Vacuum preloading combined with other soil improvement methods could improve the soil with the lower average water content and the higher average shear strength. Full article

(This article belongs to the Special Issue State-of-the-Art of Geosynthetic Engineering for Sustainable Construction)

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