The present study provides an insight into the effect of recycled carpet fibre on the mechanical response of clean sand as backfill material subjected to monotonic loading and cyclic loading as well as post-liquefaction resistance of both unreinforced and carpet fibre reinforced soils. To achieve these goals, a series of multi-stage soil element tests under cyclic loading event resulting in liquefaction

Soil arching and tensioned membrane effects are two main load transfer mechanisms for geosynthetic-reinforced pile-supported (GRPS) embankments over soft soils or voids. Evidences show that the tensioned membrane effect interacts with the soil arching effect. To investigate the soil arching evolution under different geosynthetic reinforcement stiffness and embankment height, a series of discrete element

This study investigated the effect of fibre reinforcement on the large strain behaviour of compacted clay samples tested using large triaxial test equipment. A novel specimen preparation method was proposed where peds of clay are compacted to closely simulate the in-situ compaction. A large number of 100 × 200 mm triaxial tests and one-dimensional compression tests were performed using reinforced and

This paper examines the hydration behaviour of polymer enhanced geosynthetic clay liners (GCLs) under both isothermal conditions and diurnal cyclical temperatures as recorded at a Melbourne landfill site. The diurnal temperature cycles introduced thermal gradients, which induced water movement downwards into the subgrade. It was found that the bulk of the thermal and hydraulic effects occurred within

This paper presents an experimental and analytical evaluation of factors affecting the interface pullout resistance of polymeric strips embedded in marginal soils, with a particular interest in supporting the partial replacement of natural sands by intensely weathered tropical soils in reinforced soil structures, which have often been considered marginal fills in design guidelines. Large-scale pullout

Geocells are three-dimensional expandable panels composed of polymers such as polyolefin polymers. Currently, geocells are being extensively used in various geotechnical engineering applications; however, its applications are limited because of the sizeable long-term deformation under constant loading and poor tensile strength. Owing to the rapid growth rate of geocells, it has become necessary to

Six geosynthetic-reinforced soil (GRS) retaining walls supporting bridge approach roads of an overpass bridge in China exhibited a series of structural problems after 18 years of service. Field investigations demonstrated that the major structural problems consist of excessive lateral facing displacement, settlement and damage of facing panels, and pavement cracks above the GRS retaining walls. The

This study proposed an analytical model to investigate strain transfer mechanism between FBG sensor and measured geogrid. Both geometric and mechanical parameters (bonding length, bonding thickness, bonding width, and Young's modulus) of interaction interface can be taken into account in this model. Both laboratory tensile tests of geogrid and experimental data in published literatures were used to

Wicking geotextile has been increasingly utilized in field projects to mitigate water-related roadway problems. The previous studies showed that the wicking geotextile could provide mechanical stabilization, serve as capillary barrier, and enhance lateral drainage. The wicking geotextile differentiates itself from non-wicking geotextiles by providing capillary or wicking drainage in unsaturated conditions

A laboratory investigation was conducted on two different conventional GCLs (one with fine granular and another one with powdered bentonite) to explore the effect of prehydration and permeant fluid; GCL desiccation on the interface transmissivity, θ, between the interfaces of a 1.5 mm-thick high-density polyethylene (HDPE) geomembrane (GMB) and a GCL. The study also aimed to assess the self-healing

An efficient and accurate reliability-based design of the geosynthetic-reinforced slopes (GRS) using the pseudo-static and modified pseudo-dynamic framework is proposed in the present study. Deterministic formulation used in the present study is made robust with the help of nonlinear constrained optimization. The collocation based stochastic response surface method (CSRSM) is used to probabilistically

The problem of accurate prediction of deformations of reinforced soil structures under serviceable loading is discussed in this paper. First, a short overview of existing guidelines and methods is presented. Second, an analytical approach developed in IBW PAN to calculate horizontal and vertical deformations of such structures is described. Third, results of the verification of the proposed methodology

In this study, the downstream slope of a dam impounding the upper reservoir of Lam Ta Khong (LTK) hydroelectric energy storage in Thailand was found to slide at a higher pace during the rainy season. After a thorough site investigation, laboratory tests, and numerical modeling to identify the main cause of the movement, it was found that as rainfall infiltrated the upper soil layer, the claystone of

A rigorous upper bound formulation is established for reinforced soils considering both the tensile rupture of the reinforcement and the relative slippage of the reinforcement-soil interface. To represent its finite tensile strength and negligible compressive strength, a novel strategy is proposed to calculate the plastic dissipation rate of the reinforcement without the incorporation of stress variables

Encased stone columns are vertical inclusions in soft soils formed by gravel wrapped usually with a geotextile. Their critical length is the one where further lengthening of the column provides a negligible improvement and it is therefore not effective to build columns longer than it. This paper aims to obtain common values of the critical length using simplified two-dimensional axisymmetric and full

The instability of railway tracks including mud pumping, ballast degradation, and differential settlement on weak subgrade soils occurs due to cyclic stress from heavy haul trains. Although geotextiles are currently being used as a separator in railway and highway embankments, their ability to prevent the migration of fine particles and reduce cyclic pore pressure has to be investigated under adverse

Although the use of Geosynthetic Reinforced Soil (GRS) bridge abutments has been increasing, the seismic performance of such structures has remained a significant concern due to their unknown behavior in load-bearing and stress distribution under bridge load and seismic conditions simultaneously. This paper investigates the static and dynamic response of GRS bridge abutment. A series of numerical models

Applications of geofoam for buried culverts/pipes keep increasing; however, the design of such applications is still challenging due to lack of full-scale studies. Considering practice needs, a full-scale field study was carried out to investigate the effectiveness of different geofoams with different layouts to reduce overburden stresses on deeply buried, large-size culverts. Among the eight test

Transmission tower foundations experience large vertical uplift forces during their lifetime. These forces can be resisted by providing anchor foundations below the tower. In this study, laboratory experiments were conducted to investigate the pullout capacity of inclined plate anchors in dry sand. The capacity of inclined anchor significantly improved in the presence of geogrid reinforcement on top

Expansion of bridge girders in summer moves integral bridge abutments toward backfill, causing high lateral earth pressures behind the abutment. Some backfill material slumps downward and toward the abutment when the abutment moves away from the backfill due to bridge girder contraction in winter. Placement of geogrids within the backfill can increase stability of the backfill while placement of compressible

This paper provides a more realistic representation of the soil-geogrid interface in indirectly activated geogrids. A new testing apparatus is designed using transparent soil that allows an unobstructed observation of the interface to investigate the interaction occurring along the reinforcement. In this investigation, the reinforcement is indirectly activated by the deformations of the surrounding

Effective mitigation of seismic-induced ground hazards requires an improved understanding of ground response in terms of earthquake wave propagation and ground deformation. Here, this paper examines the effects of geosynthetic-encased stone columns (ESCs) and ordinary stone columns (SCs) on the acceleration amplitude and frequency content responses of sand profiles, and the deformation of the ground

The fundamental mechanisms controlling shear strength and deformability behavior of clay-fiber mixtures have still not been well established, nor the constraints that may affect their performance of shearing under different drainage conditions. This study aims to understand the behavior of a clay soil mixed with polypropylene fibers using results from drained and undrained triaxial compression tests

A laboratory testing that simulates the mechanisms of a geosynthetic-reinforced layer was used to assess the impact of rainwater infiltration on reinforcement loads and strains in mechanically stabilized earth (MSE) walls. The testing device allows measuring loads transferred from a backfill soil subjected simultaneously to surcharge loading and controlled irrigation. Load-strain responses of geosynthetic-reinforced

In this paper, the nonlinear consolidation behavior of soft soil with vertical drains considering well resistance and smear effect under cyclic loadings was investigated. Using the variables separation method, a series of analytical solutions were derived to calculate the excess pore water pressure and the average degree of consolidation of the soil subjected to various cyclic loadings including trapezoidal

At present, the design of geosynthetic-reinforced soil structures is executed with reference to the tensile strength of the reinforcement obtained from in-air short-term tensile tests, decreasing this value by means of several factors. Among these, the creep effect resulting from in-air tensile creep tests reduces tensile strength the most. Consequently, this procedure does not take into account the

Experiments are conducted to quantify leakage through holes in a geomembrane (GMB) overlain by tailings with 30% fines and underlain by a well-graded gravel. Analytical and empirical equations for predicting leakage through a circular hole are used to analyze the data. Test results show that changing the hole shape from circular to noncircular increases the leakage. Leakage through 2000 mm2 triangular

An electro-osmotic consolidation (EO) combined with vacuum preloading (VP) was investigated on marine clay using laboratory tests. To improve consolidation efficiency and reduce the settlement difference, a new prefabricated device was designed to combine EO and VP for the tests. The results indicated that the vacuum preloading with intermittent electro-osmotic consolidation (VP–I-ECM) provided more

The typical problem that occurs when the conventional vacuum preloading (CVP) method is applied to dredged soil is that the drainage is impeded, permeability is progressively reduced, and clogging occurs in prefabricated horizontal drains (PHDs). This paper proposes a method in which air booster through PHDs under vacuum preloading to reinforce newly dredged soil, and thereby solve the clogging problem

In this paper, the seismic performance of wall-type gravel and rubber drains as a liquefaction countermeasure in silty sand has been addressed using a series of 1 g shaking table tests. In these tests, the liquefaction resistance of silty sand was studied by changing soil relative density, silt content, number of walls, and materials of drainage walls. In order to evaluate shear wave propagation, the

Nano-zeolite was used in the present study as a substitute for a part of lime and then inclusion polypropylene fiber in stabilized soil matrix to develop the soil stabilization method with lime and to improve the efficiency of this technique. In so doing, specimens of soft soil with 5, 10 and 15% of modifier L (lime), LZ (lime-nano-zeolite) and LZF (lime-nano-zeolite-fiber) were prepared, and were

The self-healing of a GCL with a circular hole is examined in experiments where the GCL, overlain by geomembrane, is hydrated from a silica sand subgrade (SSS) having three different pore water chemistries. Factors considered included: hole size, subgrade initial moisture content wfdn, GCL mass per unit area, and overburden stress (20–100 kPa). GCL self-healing is better for wfdn = 16% than for wfdn = 10%

The paper reports the construction and surcharge load-testing of three (3) large-scale (~2.50 m-tall) GRS bridge abutment models in an outdoor test station to investigate the influences that the facing type and reinforcement spacing could have on their load-bearing performance. The facing types examined included cored Concrete Masonry Units (CMU) in Model #1 and much larger solid concrete blocks in

This paper presents pullout test results on conventional (ordinary) and diagonally enhanced geocells under surcharge pressures of 3, 13, 23 and 33 kPa. Extensive pullout tests on scaled geocells embedded in silica sand are performed to investigate the effects of improvements on load-deformation response, strength and stiffness. Conventional web-shaped geocells are having a small stiffness when subjected

In the internal stability design of reinforced soil structures, the existing design provisions consider only axial pullout of the reinforcement. However, the kinematics of deformation clearly shows the reinforcement to be subjected to an oblique pull along the failure surface. The overall response due to oblique pull of reinforcement can be considered as cumulative individual responses of axial and

This paper presents a novel suction-controlled chamber that permits the determination of the full water retention curves of geosynthetic clay liners (GCLs) under non-uniform temperature-stress paths. It investigates field conditions encountered in brine ponds (low confining stress settings) and heap leach pads (high confining stress settings) during construction and operation stages. Consequently,

This study investigates the seismic performance of geosynthetic-reinforced modular block retaining walls backfilled with cohesive, fine grained clay-sand soil mixture. Shaking table tests were performed for three ½ scaled (wall height 190 cm) and ¼ scaled model walls to investigate the effects of backfill type, the influence of reinforcement length and reinforcement stiffness effects. The El Centro

Conventional methods for measuring the deformational response of geosynthetics, such as the linear variable differential transformers (LVDTs), strain gauges, and extensometers have several limitations in fully determining the complete strain distribution in geosynthetics. This paper presents a multi-camera based photogrammetric method to track the 3D full-field displacements of geosynthetics during

The performance of five different GCLs (two GCLs with standard sodium bentonite and three GCLs with polymer enhanced bentonite) subjected to three different climatic modes of wet-dry cycles simulating conditions to which a GCL might expose in cover systems over a prolonged time is reported. The wetting cycles lasted for 8 h, while the drying cycles varied between 16 h, seven days, and 14 days. It is

Hydraulic conductivity of seven geosynthetic clay liners (GCLs) to synthetic coal combustion product (CCP) leachates were evaluated in this study. The leachates are chemically representative of typical and worst scenarios observed in CCP landfills. The ionic strength (I) of the synthetic CCP leachates ranged from 50 mM to 4676 mM (TCCP-50, LRMD-96, TFGDS-473, LR-2577, HI-3179 and HR-4676). One of the

In this study, a two-dimensional consolidation solution for geotextile tubes filled with fine-grained material was presented. The solution is based on a combination of various methods that were modified or extended to take into account the change in tube shape, the nonlinear interaction between the soil and geotextile, and the water content distribution of the tube during consolidation. Using the proposed

The assumption with the biggest impact on the design of geosynthetic-reinforced soils above voids is the presence and degree of soil arching, which affects the predicted applied stress on the geosynthetic. A series of centrifuge tests were conducted to investigate the soil arching in geosynthetic-reinforced soils with measurements of the soil stresses and observation of soil and geosynthetic deformation

This paper aims to establish an analytical model on vacuum consolidation of dredged slurry treated by PVD with special considerations on the clogging effects. A series of laboratory tests have been conducted to characterize the temporal/spatial variations of the clogging zone and the vacuum pressure in soil. Based on the nonlinear relationship between the compressibility, the permeability and the void

Buried pipes may transport substances that can be harmful to people and the environment. These structures may be subjected to damages caused by soil movements and external interference, such as surcharges and excavations. Different applications of geosynthetics have demonstrated that they can be used to protect buried pipes and to minimize the consequences of pipe burst. This paper discusses results

Abstract The interface transmissivity (θ) of two multicomponent geosynthetic clay liners (GCLs) is investigated upon hydration and permeation with a highly saline solution (TDS ≈ 260,000 mg/l; Na+ ~ 95,000 mg/l; K+~12,000 mg/l) at two stress levels (10 kPa and 150 kPa). One GCL had a smooth 0.2 mm-thick coating whereas the second GCL had a textured 1 mm-thick coating. For both GCLs, the interface transmissivity

Abstract Particle flow code in three dimensions (PFC3D) is used to investigate the bearing capacity and mechanism of a geomembrane-lined landfill under construction loading. The soils and the geomembranes are simulated by numerous balls and parallel bond, respectively. The initial states and loading processes of geomembrane-lined soil are simulated by PFC3D method. The displacement vector diagram,

Abstract A one-year field monitoring of a geogrid reinforced municipal solid waste (MSW) slope was conducted in the Xingfeng Landfill. Settlement tubes, strain gauges and earth pressure cells were used to measure the vertical settlement, the reinforcement strains and the vertical earth pressures in the reinforced MSW slope, respectively. During the monitoring period, the waste sliding occurred and

Abstract This paper presents the results of laboratory scale plate load tests on transparent soils reinforced with biaxial polypropylene geogrids. The influence of reinforcement length and number of reinforcement layers on the load-settlement response of the reinforced soil foundation was assessed by varying the reinforcement length and the number of geogrid layers, each spaced at 25% of footing width

Abstract A triple-layer composite liner consisting of a geomembrane liner (GMB), a geosynthetic clay liner (GCL) and a compacted clay liner (CCL) is commonly used at the landfill bottom liner system to isolate the contaminated leachates. In this paper, one-dimensional quasi-steady-state small deformation model (SDSS) was developed to investigate the behavior of organic chemicals transport in landfill

Abstract This paper presents analytical solutions for predicting one-dimensional contaminant diffusion in a four-layer sediment-cap system, which is typically encountered in subaqueous in-situ capping of contaminated sediments. The sediment-cap system is comprised of, from top to bottom, a layer of capping material (e.g., clean sand), a layer of reactive core mat (RCM), a layer of contaminated sediment

Abstract The objective of the paper is to give an update in key topics related to performance issues of barrier systems for landfills. The objective of using barrier systems is to minimize the impact of contaminants on the surrounding environment. To achieve this goal puncture protection of the geomembrane must be ensured. An update is first given with respect to this matter. The question of the stability

Abstract Increased traffic volume in China has made it necessary to increase road capacities by widening embankments. Some of these widened embankments are located in thick soft ground that requires extra improvement beforehand. This paper presents a case study using the combined vacuum and surcharge preloading method to improve the thick soft clay foundation for an embankment widening project in Lianyungang

Abstract Geosynthetic clay liners (GCLs) are widely used in landfill and heap-leach facility cover system for mitigating rainfall infiltration and gas migration into atmosphere. Laboratory tests were conducted to investigate methane diffusion and advection through GCLs. Gas permeability coefficient of GCL for the case with moisture content = 47.5% is one and two orders of magnitude greater than the

Abstract Geosynthetic clay liners (GCLs), which have a very low permeability to water and a considerably high self-healing capacity, are widely used in liner systems of landfills. In this study, a series of experimental tests were carried out under complex conditions on typical commercial GCLs from China. In particular, the effects of pH values and lead ions (Pb2+) were tested in addition to other

Abstract Textured geomembrane (GMB) and nonwoven geotextile (GTX) are usually used together in liner systems of MSW landfills, but the low shear strength of GMB/GTX interface is extremely detrimental to the stability of landfills, especially under earthquake loading. To study the dynamic shear strength of the GMB/GTX interface, a series of displacement-controlled cyclic direct shear tests are conducted

Abstract The high ionic strength of the porewater in red mud (bauxite liquor from digestion) can suppress swelling of montmorillonite, resulting in geosynthetic clay liners (GCLs) that are too permeable to be effective as liners in red mud disposal facilities. Bentonite-polymer composite GCLs (BPC GCLs) have been developed as more resilient lining materials, and some BPC GCLs have been shown to have

This paper examines two needle-punched geosynthetic clay liners' water retention behaviour at high suction ranges using the vapour equilibrium technique where super-saturated salt solutions controlled the relative humidity. This study shows that the bentonite form and its mineralogy affect the absorption/desorption of GCLs and their corresponding water retention curves. In particular, a granular bentonite-based

Many analytical and numerical analysis and design methods for geosynthetic-reinforced soil structures require a single-value (constant) estimate of reinforcement stiffness. However, geosynthetic reinforcement products are rate-dependent polymeric materials meaning that they exhibit time and strain-dependent behaviour under load. Hence, the appropriate selection of a constant (elastic) stiffness value

In this study, the performance of the stone column encased with conductive jute geotextile in improving the characteristics of soft clay under k0 stress condition was evaluated using a custom-designed large-scale consolidation test setup. The electrokinetic-encased stone column (e-ESC) was designed as a cathode, while mild steel rods were chosen as anodes, and by applying a voltage gradient of 0.1 V/mm