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Abstract When it comes to the geosynthetic-reinforced soil structures’ structural design, the analysis of deformation is of the highest relevance. In spite of this, the academic literature lays a substantial amount of attention on the potential of artificial intelligence approaches in efficiently addressing the many challenges that are faced in geotechnical engineering. The investigation of the possible use of approaches based on machine learning for the purpose of forecasting the geogrid-reinforced soil structures’ deformation ( $${\text{Dis}}$$ Dis ) was the major focus of this study. These efforts are made to reduce the time and cost of numerical modeling. This study aimed to enable computers to learn patterns and insights from data to make accurate predictions or decisions about unseen data. This paper introduces novel systems that coupled the Beluga whale optimizer ( $${\text{BWH}}$$ BWH ), Henry gas solubility optimization ( $${\text{HGSO}}$$ HGSO ), gannet optimization algorithm ( $${\text{GOA}}$$ GOA ), and Harris hawks optimizer ( $${\text{HHO}}$$ HHO ) with adaptive neuro-fuzzy inference system ( $${\text{ANFIS}}$$ ANFIS ). A dataset was created by gathering 166 finite element analyses accomplished in the literature. Between four $${\text{ANFIS}}$$ ANFIS systems, the integrated one with $${\text{GOA}}$$ GOA got the largest accuracy value, accounting for 0.9841 and 0.9895 in the train and test stages, better than $${\text{ANF}}_{{{\text{BWH}}}}$$ ANF BWH , followed by $${\text{ANF}}_{{{\text{HH}}}}$$ ANF HH . It was seen from $${\text{U}}_{{{95}}} { }$$ U 95 that the $${\text{ANF}}_{{{\text{GOA}}}} { }$$ ANF GOA scenario exhibits the least level of uncertainty in comparison to other models, hence demonstrating its greater capacity for generalization. Between four $${\text{ANFIS}}$$ ANFIS systems, the most accurate system with the lowest $${\text{OBJ}}$$ OBJ value is $${\text{ANF}}_{{{\text{GOA}}}}$$ ANF GOA at 2.6098, followed by $${\text{ANF}}_{{{\text{BWH}}}}$$ ANF BWH at 2.8002. Sensitivity analysis depicts that removing the surcharge $$\left( q \right)$$ q parameter from the input group has a considerable negative impact on output accuracy.

Design guidelines for geosynthetic-reinforced soil (GRS) walls in a tiered configuration are often limited to two tiers with zero batter. To facilitate rational expansion of current design, this paper extends the current top-down procedure, based on limit equilibrium analysis, from single GRS walls to multitiered walls. For a given factor of safety, the required reinforcement tension distribution and connection load are determined for each reinforcement layer. The approach considers the impact of potential compound failures. Parametric studies are conducted to investigate the influences of backfill soil, wall geometry (i.e., wall batter, number of tiers, and offset distance), and reinforcement layout. The results demonstrate quantitively that increasing the internal friction angle of backfill soil, wall batter, number of tiers, and offset distance reduce the required maximum tension. The tiered configuration in GRS walls leads to localized increase in connection load at the toe elevation of each tier. Using close reinforcement spacing could significantly reduce the connection load. The critical offset distance is realized when the reinforcement in each tier acts internally independent of others. Its value decreases with increasing the internal friction angle of backfill soil, wall batter, and number of tiers. The observations in this study are significant in the context of optimal design of multitiered GRS walls. [ABSTRACT FROM AUTHOR]

Significant savings in carbon emissions, cost, and time could be achieved via the reduction in maintenance frequency, capital costs of track construction, and land used. Geosynthetic-reinforced soils offer such sustainable solutions. The experimental work presented in this paper investigates the long-term performance of a Geosynthetic-Reinforced Soil Retaining Wall (GRS-RW) system as an alternative to the conventional railway embankment. Full-scale testing was carried out on three sleeper sections of ballasted and slab tracks by simulating train loads cyclically, phased to 360 km/h. The tracks were supported by either a low-level fully confined conventional embankment or a GRS-RW substructure. The substructures were formed of a 1.2 m deep subgrade and frost protection layer, in accordance with high-speed railway design standards. The overall aim was to assess the performance of the tracks, in terms of transient displacements and total settlements. It was observed that once the GRS-RW system reached its active state, it deformed in a very similar way to a conventional embankment despite the fact that the GRS-RW system is less confined than the conventional embankment. The results indicate that the cumulative settlement of the slab track, which is due to the plastic deformation of the soil, is significantly less than that of the ballasted track, which is primarily caused by the movement of the ballast particles. [ABSTRACT FROM AUTHOR]

The paper aims to evaluate the pseudostatic seismic bearing capacity of shallow foundations on geosynthetic-reinforced granular soil subjected to inclined/eccentric combined loading. This is achieved through a comprehensive set of lower-bound finite-element limit analysis (LB FELA) simulations adopting the second-order cone programming. The pseudostatic seismic loading is incorporated into the element equilibrium equations as body forces. Both sliding and structural modes of geosynthetic failure are simulated within the FELA framework. The influences of pseudostatic acceleration, embedment depth (u), and the ultimate tensile strength (Tu) of the reinforcement layer on the failure mechanism, bearing capacity ratio, and failure envelope of the overlying obliquely/eccentrically loaded shallow foundation are thoroughly investigated and discussed. It is generally concluded that at a given reinforcement embedment depth, failure envelopes shrink substantially with the increase of the seismic horizontal acceleration and the reduction of the geosynthetic ultimate tensile strength. [ABSTRACT FROM AUTHOR]

The article presents an experimental study of a geosynthetic-reinforced soil (GRS) bridge abutment (BA). The BAs are seated on a saturated soft foundation layer and support a 16 m long concrete bridge. Laboratory tests were conducted on the foundation soil, geogrid, and fill material. The BA is constructed from 14 geogrids and has a total height of 4.2 m. The strain values in the geogrids were measured and recorded during the construction of the abutments and after installation of the bridge structure. The test results show that more than 50% of the total strain in the geogrids was developed during the construction of the BAs, mostly embedded in the ground. The remainder of the measured strain was a consequence of installing the prefabricated bridge girders, back fill placement, concreting the top slab, and placing the asphalt concrete. The strain distribution along the geogrids shows that the maximum strain was recorded below the sill, and was 50% higher than at the center of the BA. Based on an analysis of the construction costs, it can be concluded that conventional reinforced concrete abutments could cost up to five times the amount of optimally designed GRS-BAs. [ABSTRACT FROM AUTHOR]

Geosynthetic-reinforced soil (GRS) technology has been used worldwide since the 1970s. An extension to its development is the application as a bridge abutment, which was initially developed by the Federal Highway Administration (FHWA) in the United States, called the GRS—integrated bridge system (GRS-IBS). Now, there are several variations of this technology, which includes the GRS Integral Bridge (GRS-IB) developed in Japan in the 2000s. In this study, the GRS-IB and GRS-IBS are examined. The former uses a GRS bridge abutment with a staged-construction full height rigid (FHR) facing integrated to a continuous girder on top of the FHR facings. The latter uses a block-faced GRS bridge abutment that supports the girders without bearings. In addition, a conventional integral bridge (IB) is considered for comparison. The numerical analyses of the three bridges using Plaxis 2D under static and dynamic loadings are presented. The results showed that the GRS-IB exhibited the least lateral displacement (almost zero) at wall facing and vertical displacements increments at the top of the abutment compared to those of the GRS-IBS and IB. The presence of the reinforcements (GRS-IB) reduced the vertical displacement increments by 4.7 and 1.3 times (max) compared to IB after the applied general traffic and railway loads, respectively. In addition, the numerical results revealed that the GRS-IB showed the least displacement curves in response to the dynamic load. Generally, the results revealed that the GRS-IB performed ahead of both the GRS-IBS and IB considering the internal and external behavior under static and dynamic loading. [ABSTRACT FROM AUTHOR]

In this research, a numerical investigation was conducted to study the effects of backfill constitutive behavior on the vertical and horizontal deformations of geosynthetic-reinforced soil (GRS) piers under static axial loads. A finite-difference program was used to model full-scale GRS piers. The backfill soil was simulated using three constitutive models: the elastic-perfectly-plastic Mohr-Coulomb model, the plastic-hardening model, and the plastic-hardening model combined with strain-softening behavior. The results showed that the deformation response of GRS piers under service loads is satisfactorily predicted by the plastic-hardening model. At ultimate failure loads, however, only the model accounting for the plastic-hardening and the strain-softening behaviors was judged to reasonably capture the behavior of GRS piers. The relative displacement of soil and geotextile at the soil–geotextile interface was also investigated. The results showed that under working conditions with small applied load, there is no sliding between the soil and geotextile; however, as the load increases, sliding is first initiated at the corners of the pier and progressively mobilized toward the center of the pier. A parametric study on the effects of soil–geotextile interface properties on the deformation behavior of GRS piers under axial loading was also conducted using the validated plastic-hardening model combined with strain-softening behavior. It was found that increasing the interface friction angle decreases the settlement of GRS piers when the axial strain is greater than 2% for piers with a concrete masonry unit (CMU) facing and 4% for piers without CMU facing. The results suggest that when calibrating the interface friction angle (or cohesion), the postyielding response of GRS pier should be used. [ABSTRACT FROM AUTHOR]

The article presents a parametric study of optimal designs for geosynthetic-reinforced soil (GRS) bridge abutments. A mixed integer design optimization model GRS-BA was developed, which is comprised of an accurate objective function of the construction costs. The cost objective function was constrained by a set of geotechnical and design conditions that were in accordance with current practice rules and recommendations. The optimal design recommendation for GRS bridge abutments was developed. A typical example of such an abutment is presented in order to compare design solutions derived from conventional design methods with solutions obtained from the proposed optimal design procedure. [ABSTRACT FROM AUTHOR]

Geosynthetic-reinforced soil (GRS) technology has been used worldwide since the 1970s. An extension to its development is the application as a bridge abutment, which was initially developed by the Federal Highway Administration (FHWA) in the United States, called the GRS—integrated bridge system (GRS-IBS). Now, there are several variations of this technology, which includes the GRS Integral Bridge (GRS-IB) developed in Japan in the 2000s. In this study, the GRS-IB and GRS-IBS are examined. The former uses a GRS bridge abutment with a staged-construction full height rigid (FHR) facing integrated to a continuous girder on top of the FHR facings. The latter uses a block-faced GRS bridge abutment that supports the girders without bearings. In addition, a conventional integral bridge (IB) is considered for comparison. The numerical analyses of the three bridges using Plaxis 2D under static and dynamic loadings are presented. The results showed that the GRS-IB exhibited the least lateral displacement (almost zero) at wall facing and vertical displacements increments at the top of the abutment compared to those of the GRS-IBS and IB. The presence of the reinforcements (GRS-IB) reduced the vertical displacement increments by 4.7 and 1.3 times (max) compared to IB after the applied general traffic and railway loads, respectively. In addition, the numerical results revealed that the GRS-IB showed the least displacement curves in response to the dynamic load. Generally, the results revealed that the GRS-IB performed ahead of both the GRS-IBS and IB considering the internal and external behavior under static and dynamic loading.

This study presents a series of numerical analyses investigating the impact of rainfall on the performance and design of geosynthetic-reinforced soil slopes (RSSs). The importance of considering regional hydrological conditions for designs of RSSs, particularly when marginal soil is used as backfill, is demonstrated and highlighted. RSSs with backfills containing five different fines contents subjected to various combinations of initial hydraulic conditions and major rainfall events were modeled. The input rainfall was determined from the rainfall intensity–duration–frequency (I–D–F) curves to realistically account for the impact of regional hydrological conditions. The hydraulic responses and stability of the RSSs including their porewater pressure development and factor of safety were then evaluated and compared. The results revealed that the applied rainfall scenarios had little influence on the performance of RSSs with high-quality backfills (i.e. backfill with low fines content), whereas those with prolonged rainfall duration substantially affected the performance of RSSs with high fines content backfills. Rainfall thresholds were established for the RSSs with various backfills and initial conditions and compared with the regional I–D–F curves to provide a simplified and robust method for facilitating backfill selection and assessing the failure risk of RSSs. [ABSTRACT FROM AUTHOR]

Compaction equipment worked behind the retaining walls causes additional lateral earth pressures acting on the wall. The effect of compaction-induced stress (CIS) usually neglected when designing the retaining walls. Geosynthetic-Reinforced Soil walls (GRS walls) have increasing popularity in Egypt in the last years. The earth pressure at the facing of a Geosynthetic Reinforced Soil wall (GRS wall) is different from that in the natural soil. The internal lateral pressure in the GRS soil is governed by compaction-induced stresses (CIS) and additional confining effects that the reinforcement provides to the soil. The compaction-induced stress for GRS wall is difficult to be predicted during the design stage because it depends on the characteristics of compaction equipment and other factors. The objectives of the research are:1) Studying the effect of compact the backfill of GRS wall by vibratory plates on the internal stability, the external stability, and the foundation soil for GRS wall. 2) Evaluating the performance of the various types of vibratory plates which used to compact the backfill for GRS wall. So, a finite element analysis using GEO5 program was used to achieve these objectives. Finally, the recommendations for the design and construction of GRS walls were highlighted. [ABSTRACT FROM AUTHOR]

Abstract In this study, both two-dimensional (2D) and three-dimensional (3D) numerical analyses were carried out to evaluate the performance of geosynthetic-reinforced soil (GRS) piers. The numerical models were first calibrated and verified against test results available in the literature. A parametric study was then conducted under both 2D and 3D conditions to investigate the influences of reinforcement tensile stiffness, reinforcement vertical spacing, and a combination of reinforcement stiffness and spacing on the performance of GRS piers under vertical loading. Numerical results indicated that the effect of reinforcement spacing was more significant than that of reinforcement stiffness. The use of closely – spaced reinforcement layers resulted in higher global elastic modulus of the GRS pier, smaller lateral displacements of pier facing and volumetric change of the GRS pier, lower and more uniformly-distributed tension in the reinforcement, and larger normalized coefficients of lateral earth pressure. This study concluded that a 2D numerical model gave more conservative results than a 3D model. [ABSTRACT FROM AUTHOR]

Road infrastructures are a very important component of the world's total transportation network. Investment in its construction and maintenance is significant on a global scale. The paper presents some results from an environmental study of a geosynthetic-reinforced soil integrated bridge system. The Pavlovski potok stream in Slovenia was used as a demonstration case for this study. It is the first GRS bridge system with full-height rigid (FHR) facings in Europe. It was constructed at the end of 2014. The goal of these analyses was to compare two different types of bridges: the new GRS bridge system, which is comprised of a simple girder partially structurally integrated to FHR facings of GRS bridge abutments and a conventional reinforced concrete road bridge. The results of an environmental life cycle assessment (LCA) show that the GRS bridge system has a much lower environmental impact than an equivalent bridge conventionally built with reinforced concrete. [ABSTRACT FROM AUTHOR]

This paper presents a numerical investigation of the performance of geosynthetic-reinforced soil (GRS) bridge abutments under static loading conditions. Simulations were conducted using a finite-difference program to model the Founders/Meadows GRS bridge abutment during construction and service. Simulated results are in good agreement with field measurements, including displacements, lateral and vertical earth pressures, and tensile strains and forces in reinforcement. The simulations also indicate that horizontal restraint from the bridge structure has a significant influence on abutment deflections. A parametric study was then conducted to investigate the performance of a single-span full bridge system with two GRS abutments, including effects of bridge contact friction coefficient, backfill soil relative compaction, backfill soil cohesion, reinforcement spacing, reinforcement length, reinforcement stiffness, and bridge load. Results indicate that backfill soil relative compaction, reinforcement spacing, and bridge load have the most significant influence on lateral facing displacements and bridge footing settlements for GRS abutments. Differential settlements between the bridge footing and approach roadway were small for all simulated conditions. [ABSTRACT FROM AUTHOR]

Geosynthetic-reinforced soil (GRS) walls have been increasingly used to support bridge foundations as abutment walls. On the GRS abutment wall, large footing loads are applied adjacent to the wall facing. However, so far limited studies have been conducted to investigate the performance of GRS abutment walls subjected to static or dynamic loading. This study presents a series of model tests on the GRS walls to evaluate the effects of several influence factors, including the offset distance of a strip footing, the width of the strip footing, the length of geogrid reinforcement, and the connection mode between geogrid and facing, on the ultimate bearing capacities of the strip footings on the GRS walls. The settlements of the loading plate and the lateral displacements of the wall facing during loading were monitored. Thin colored sand layers were placed in the backfill sand to observe possible failure surfaces developing in the GRS walls. The experimental results showed that the footings on the GRS walls with 0.7H (H is the wall height) long reinforcement reached the maximum bearing capacities at the offset distances of 0.3 H and 0.4 H in the wall tests with mechanical and frictional connections, respectively. When the GRS walls had the geogrids with longer reinforcement length (2H), the ultimate bearing capacity increased with the offset distance of the footing and became constant when the offset was greater than 0.4H. It was observed that the failure surface started from the edge of the footing and exited from the facing of the wall. Based on the limit equilibrium analyses, under the footing loading, the slip surfaces by Spencer's two-part wedge method had a good agreement with those observed in the model tests. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the results of numerical parametric study of free-standing simple geosynthetic-reinforced soil (GRS) walls under real multidirectional ground motion shaking. The predictions were made using a validated finite element computer program. Design parameters, such as (1) wall height, (2) wall batter angle, (3) soil friction angle, (4) reinforcement spacing, and (5) reinforcement stiffness, were evaluated in the study. Prior to the parametric study, the extent of finite element model (FEM) boundary was verified in order to minimize the boundary effect. Results of parametric study were compared against the values determined using the Federal Highway Administration (FHWA) allowable stress design methodology. It was found that the FHWA methodology overestimates the reinforcement tensile load as compared to the FEM results. Multivariate regression equations were developed using FEM results for the various seismic performances based on multiple design parameters that are essential in the design of GRS walls. In particular, the prediction equations for wall facing horizontal displacement, wall crest settlement, and reinforcement tensile load are presented. The prediction equations can provide first-order estimates of the seismic performances of free-standing simple GRS walls. [Copyright &y& Elsevier]

The article discusses a study which examines the results of shaking-table tests on small-scale models of bridge types within the framework of the single-degree-of-freedom theory. It says that the stability of the bridge against dynamic excitations increases the initial natural frequency via the initial stiffness and decrease in the rate of stiffness during cyclic loading. It mentions the characteristics of the geosynthetic-reinforced soil (GRS) integral bridge such as bearings and girder.

Abstract: This paper presents the results of numerical simulation of three full-scale geosynthetic-reinforced soil walls that were seismically loaded by a shaking table. Material model parameters were determined from the available laboratory data. In particular, the backfill was simulated with a cap model with parameters dependent of stress level. Hardening parameters of cap model were determined from hyperbolic relation derived from the relevant hydrostatic compression tests. A discussion on the calibration of modeling parameters is presented. Responses compared include (a) maximum wall displacement, (b) maximum backfill settlement, (c) maximum lateral earth pressure, (d) maximum bearing pressure, (e) maximum reinforcement tensile load, (f) absolute maximum acceleration in reinforced soil zone, and (g) absolute maximum acceleration in retained soil zone. Qualities of simulations were evaluated and are discussed. It was found that not all the calculated results agree well with the measured data. However, strong inference or high confidence is anticipated for the closely matched responses such as lateral earth pressure and horizontal displacement utilizing the calibrated model described herein. As indicated by the calculated results, seismic wall displacement decreases with decreasing reinforcement spacing. Factors responsible for comparison discrepancy are discussed. Variability within the measured data is thought to have contributed to some of the comparison discrepancies. [Copyright &y& Elsevier]

The results of an experimental study conducted on two 1:2 reduced-scale geotextile-reinforced soil retaining walls are presented and discussed. El Centro earthquake and sinusoidal harmonic motion excitations were applied to the 1.9 m tall models. The design parameter investigated was the reinforcement length (L/H = 0.9 in the 1st model and L/H = 0.6 in the 2nd model). The results were analyzed to evaluate the acceleration amplification, strains in the reinforcement layers and facing wall deformation. The test results showed that in both experiments the walls were in fact designed to behave rigidly and almost no residual displacements were observed on the front of the wall. The most important conclusion drawn from the experimental work was that Geosynthetic Reinforced Retaining Structures designed according to the current specifications behave very successfully under earthquake loading conditions. [ABSTRACT FROM AUTHOR]

Lade’s single hardening soil model with Cosserat rotation embodied in the finite element method is employed to investigate the behavior of geosynthetic reinforced soils with special attention to the development of shear banding. The ability of the finite element model to detect shear banding in a reinforced soil is examined against three high quality small-scale laboratory plane strain tests on Toyoura sand with and without reinforcement. These three tests were chosen because of the clear failure surfaces that developed in the soil during loading. The FEM analyses were able to reasonably simulate the plane strain laboratory tests including both unreinforced and reinforced cases. The FEM analyses gave reasonably good agreement with the experimental results in terms of global stress–strain relationships and shear band occurrences. Furthermore, and based on FE analyses of a hypothetical geosynthetic reinforced soil (GRS) retaining wall, it is shown that the geosynthetic reinforcements are very effective in hindering the formation of shear bands in GRS retaining walls when small spacing between the reinforcement layers was used. When used properly, the geosynthetic reinforcements made the soil behave as a truly reinforced mass of considerable stiffness and strength. [ABSTRACT FROM AUTHOR]

This paper synthesizes the measured behavior and experiences gained from case histories of geosynthetic-reinforced soil (GRS) bridge-supporting structures with “flexible” facings. Only bridge-supporting structures with wrapped-face, modular block face, and rock face are included in the synthesis. The case histories were grouped into two categories: in-service structures and field experiments. Four in-service structures and six full-scale field experiments from the US and abroad were reviewed. All the structures have been instrumented to monitor their performance under applied loads, with some being loaded to failure. The essential features and performance of each case history are briefly described in the paper. A table summarizing the main features of the GRS bridge-supporting structures is also presented. The table shows comparisons of the bridge-supporting structures in terms of wall height, backfill, reinforcement type, reinforcement spacing, facing type and connection, ratio of reinforcement length to wall height, maximum settlement of the loading slab, maximum lateral movement of the wall face, maximum reinforcement strain, and failure surcharge pressure. Based on the measured performance of the case histories, observations are made in relation to performance, design, and construction of GRS bridge-supporting structures. [Copyright &y& Elsevier]

This study evaluated the responses of geosynthetic-reinforced soil (GRS) abutments subjected to bridge slab loading under working stress conditions using two-dimensional finite difference numerical software. A parametric study was conducted to investigate the effects of different combinations of reinforcement spacing S v and reinforcement stiffness J , beam seat width b , and setback distance a b on the responses of the GRS abutments in terms of additional vertical stresses under the beam seat centerline Δσ v induced by the bridge slab load, additional lateral earth pressures behind the abutment facing Δσ h-facing and under the beam seat centerline Δσ h-cetner induced by the bridge slab load, and maximum tension in the reinforcement T max. Numerical analyses evaluated trapezoidal and uniform reinforcement layouts and showed that both reinforcement layouts generated similar responses of the GRS abutments. Under the same ratio of J / S v , different combinations of S v and J generated similar distributions of Δσ v , Δσ h-facing and Δσ h-center. The maximum of T max with depth decreased almost proportionally with the decrease of S v. Larger b and a b caused lower Δσ v , Δσ h-facing , Δσ h-center , and smaller T max in the upper reinforcement layers. The truncated 2 to 1 distribution method, which considers the effects of abutment facing on the Δσ v distribution, could reasonably predict the T max in the reinforcement. [ABSTRACT FROM AUTHOR]