Stability Of Embankment Research Articles

Research on slope stability assessment methods: a comparative analysis of limit equilibrium, finite element, and analytical approaches for road embankment stabilization

In this study, a comprehensive assessment of slope failure risk in man-made slopes was conducted, focusing specifically on the embankments in the excavated regions along the Tibati-Sengbe road in the Adamawa region of Cameroon. The primary objective of this study was to analyze the stability of these slopes and determine the safety factors that should be considered in their stabilization. To achieve this goal, a field survey was conducted to identify and characterize the areas at risk. The stability assessment was performed employing sophisticated numerical methods, including the Limit Equilibrium Method (LEM) utilizing the Bishop Method, the Finite Element Method (FEM) through the Plaxis Method, and the Analytical Method (AM) based on Taylor's Abacus. Ten slopes with homogeneous soil composition but varying geotechnical and geometric properties were selected as the objects for simulations, which were performed using the software packages ROCSCIENCE (Phase 2) for LEM and PLAXIS for FEM. The results indicated a high degree of consistency between the FEM and LEM methodologies, with an R2 correlation approaching 1 in their comparison. Nonetheless, the AM yielded conflicting results in 60% of cases, emphasizing the fundamental significance of numerical methods in evaluating slope stability. The findings of this study discredit the effectiveness of analytical methods in determining safety factor calculations and highlight the accuracy and reliability of the FEM and LEM techniques given their consistent results.

Numerical and parametric analyses of four unreinforced embankments on soft soils

The conventional method of estimating safety factors during various stages of construction remains prevalent for embankment stability analysis. This typically involves employing stability charts, equations, Limit Equilibrium Methods, and the Strength Reduction Method, with the Limit Equilibrium Method being the most conventional and widely adopted. Additionally, there is an increasing trend in leveraging results from instrumented embankments for performance and stability analyses, indirectly assessing parameters such as horizontal and vertical displacements, pore pressure, and soil displacement volumes. Despite the widespread acceptance of these traditional methods, many studies tend to evaluate results individually, overlooking the benefits of direct comparison for a more comprehensive analysis. This study employs a variety of methods and approaches to assess the stability of embankments under different geometries and soil conditions. The safety factors for various embankment configurations are estimated directly using two stability charts (O'Connor and Mitchell, 1977; Barnes, 1991), two stability equations (Huang, 2018; Sampa and Schorr, 2024), the Limit Equilibrium Method implemented in GeoSlope software, and the Strength Reduction Method in Abaqus and Plaxis. Conversely, the results of the soil deformability analysis are normalized for the purposes of indirect stability analysis, with the Abaqus software serving this purpose. Analyses were conducted on models featuring either a single material for both the embankment and the soil foundation or different materials for each. The elastoplastic model employing the Mohr-Coulomb failure criterion characterized the behavior of granular materials, while modified Cam-Clay models implemented in Abaqus described the behavior of soft soils. The analysis results focus on three key aspects: (i) comparison of safety factors, (ii) establishment of behavior patterns from stability and deformability analyses, and (iii) discussion of limitations, accuracies, and advantages of the assessed methods and approaches. Finally, a critical analysis addresses the impacts of varying criteria used in Abaqus and Plaxis software for determining safety factors based on the Strength Reduction Method concept.

Effects of rock content and spatial distribution on the stability of soil rock mixture embankments

Soil-rock mixture embankments are essential for infrastructure stability, particularly in high-fill construction projects. This study evaluates the effects of rock content and spatial distribution of rock blocks on the bearing capacity, stability, and failure sliding surfaces of SRM embankments through static load model tests. An Equation for Sliding Surface of Block-Rock Content and Distribution was developed to calculate sliding surfaces based on rock content and distribution, and validated it through numerical simulation experiments. The results demonstrate that rock content significantly influences embankment stability. When rock content is below 60%, the shear outlet position of the sliding surface increases, and its curvature decreases as rock content rises, thereby enhancing the bearing capacity. Beyond 60% rock content, the internal structure densifies, markedly improving stability, although further increases yield diminishing returns. Additionally, the spatial distribution of rock blocks is crucial; concentrating rock blocks at the slope crest or toe enhances stability, while distributing them in the middle reduces it. These findings offer practical guidance for optimizing the design and construction of the soil-rock mixture embankments, emphasizing the importance of appropriate rock content and spatial distribution to achieve enhanced stability and safety.

Impact of Wetting and Drying Cycles on the Hydromechanical Properties of Soil and Implications on Slope Stability

The soil-based infrastructure is the backbone of the global economy, connecting people, enhancing quality of life, and promoting health and safety. However, its vulnerabilities are becoming apparent due to climate change, mainly through frequent wetting and drying (wd) cycles. Despite few studies in the past, research showing the stability of flood embankments in the long term, incorporating the impact of wetting and drying cycles on the hydromechanical characteristics of soil, is scarce. This study aimed to assess the impact of controlled wd cycles on the hydromechanical properties of clay and silty sand soils and its implications for the stability of a typical flood embankment. Volumetric changes were monitored during the wd cycles. The soil water characteristic curve (SWCC), saturated hydraulic conductivity (ksat), effective cohesion (c′), and effective angle of internal friction (ϕ′) were measured at 1 and 10 wd cycles. The results indicated that the 10 wd cycles decreased the saturated moisture content and resulted in a flatter SWCC compared to the 1 wd cycle for clayey soil. The ksat value was also significantly higher at 10 wd cycles than 1 wd cycle for clayey soil. An insignificant difference was found in both the SWCC and ksat at 1 and 10 wd cycles for silty sand soil. The ϕ′ value for the clayey soil decreased from 28.5 to 20.1 as the wd cycles increased from 1 to 10, while c′ remained unchanged at 10 kN/m2. On the other hand, for the silty sand soil, ϕ′ increased from 34.6 to 37.5 with an increase in wd cycles from 1 to 10, and c′ remained constant at 1 kN/m2. Numerical modelling of transient water flow coupled with a slope stability analysis revealed that the stability of a flood embankment depends on the evolution of soil hydromechanical properties due to wd cycles and the duration of flooding. These findings underscore the need for proactive measures to mitigate landslide risks in regions prone to frequent wd cycles, thereby ensuring the safety and resilience of slopes and associated infrastructure.

Hydro-thermal processes and deformation of highway embankment in the active layer in a high-latitude permafrost region of Inner Mongolia in Northeast China

Construction of embankments in the permafrost region significantly changes the heat exchange conditions and hydrothermal transport processes between permafrost and the external environment, causing changes in the state of permafrost under the embankment, which in turn affects the long-term stability of embankment impacts. Considering more complex forest environment and higher technical standard for expressway than ordinary highway, the hydrothermal and deformation characteristics of the embankment are investigated through a full-scale field experimental embankment of the Genhe-Labdalin highway. Further, the study delves into the influence of changes in the active layer thickness, hydrothermal processes, and water above the frozen layer on embankment stability. The main conclusions are as follows: 1) The permafrost table, temperature, moisture and deformation of the embankment showed lateral heterogeneity, with the three-former showing a “concave shape” and the left side (sunny slope) being lower than the right side (shady slope). 2) The permafrost table appears to be unconnected (thawing interlayer), creating preferential flow, thaw zones and even through-thaw zones. 3) Accompanied by the freezing and thawing process of the embankment, the deformation of the pavement is less delayed. These findings will be helpful for better understanding the hydrothermal characteristics of embankments in different frozen ground regions, and for providing important technical guidance to ensure the safe operation of engineering projects.

GEOTECHNICAL CONDITIONS FOR THE WIDENING OF THE EXISTING EMBANKMENTS ON THE GOLUBOVCI-BAR RAILWAY SECTION, THE SECTION THROUGH SKADAR LAKE

The reconstruction of the existing embankments along the Golubovci-Bar railway line, particularly through the section that traverses Lake Skadar, represents a significant engineering challenge due to the location's specific characteristics and ecological restrictions. This area is a protected region, which limited the implementation of certain design solutions. Embankment stability analysis using the finite element methodndicated that the existing embankment does not meet the global safety factor requirements for design earthquake according to Eurocode 8. The paper presents the engineering-geological conditions of the existing embankments, as well as recommendations for their expansion and stabilization.

Влияние демпфирования по Рэлею на устойчивость земляного полотна железной дороги в условиях сейсмического воздействия

Purpose: to consider the problem of railway subgrade stability under seismic conditions. Show the need to increase stability during an earthquake. Determine the possibility of increasing seismic resistance by introducing a damping layer into the structure. Determine the optimal damping parameters, taking into account the rational use of subgrade materials. Methods: calculations of embankment stability are carried out using the method of G. M. Shakhunyants. An earthquake is taken into account through an increase in shear forces acting on the cells of the sliding massif. The maximum accelerations of the compartments are determined based on the results of finite element method dynamic calculation of a stress-strain state of the embankment during an earthquake, which is specified through an accelerogram. Results: the effectiveness of using a damping layer in the embankment structure, introduced to increase seismic resistance, has been shown. The dependence of the stability coefficient of the embankment on the Rayleigh parameters of the material composing the body of the entire embankment has been determined. For the best material parameters, the optimal thickness and position of the damping layer in the structure are determined, at which the stability coefficient takes on a standard value and the volume of the damping layer is minimal. Practical importance: as an alternative to the normative approach, the possibility of increasing the stability of a railway embankment under earthquake conditions by introducing a damping layer into the structure is presented. An algorithm for selecting optimal damping parameters has been determined in order to increase seismic resistance.

Effectiveness evaluation of cooling measures for express highway construction in permafrost regions based on GPR and ERT

Global warming and human activities are accelerating the degradation of permafrost on the Qinghai-Tibet Plateau (QTP), leading to significant settlement and cracking issues in the local express highway infrastructures. In response, the Gonghe-Yushu Express Highway (GYE) on the east edge of the QTP incorporated extensive cooling measures during its construction to enhance embankment stability. Despite these efforts, field investigations have disclosed that embankment diseases persist across various sections, including those with implemented cooling measures. This study focuses on a specific test and demonstration section of the GYE, employing a suite of cooling measures to assess their engineering effectiveness. Utilizing a combination of multi-time ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) detection, alongside on-site disease investigations and temperature monitoring, this research comprehensively evaluates the efficacy of different cooling interventions. Findings indicate that although cooling measures generally curb permafrost degradation in areas with ice-rich and ice-saturated soils, they fall short in sections with massive ground ice. Of the six cooling measures examined in the demonstration section, ventilation duct embankments emerge as the most effective, whereas crushed-rock layer embankments rank as the least. The study further reveals that the combined use of XPS insulation boards and two-phase closed thermosyphons inadequately addresses the issue of central heat accumulation in broad-width express highways, reducing uneven settlement issues but aggravating longitudinal cracking. Comparative analysis of on-site surveys and monitoring data suggests that regular application of GPR and ERT techniques can proficiently assess the performance of cooling measures.

Sediment Transport and Flood Risk: Impact of Newly Constructed Embankments on River Morphology and Flood Dynamics in Kathmandu, Nepal

AbstractFloodplain encroachment by embankments heightens flood risk. This is exacerbated by climate change and land‐use modifications. This paper assesses the impact of embankments on sediment transport, channel geometry, conveyance capacity, and flood inundation of a reach of the Nakkhu River, Nepal. Using the CAESAR‐Lisflood landscape evolution model based on a 2‐m digital elevation model, we simulate four flood scenarios with and without embankments and sediment transport: a historical 25‐year return period flood event used to design the embankments, 50‐year, 100‐year, and 1000‐year return period flood events forecast using the Generalized Logistic Model (using data from 1992 to 2017). Our results indicate that flow confinement by embankments reduces inundation by 99% (from 22.5 to 0.3 ha) for the historical 25‐year flood discharge of 42.23 and by 15% (from 28.8 to 24.4 ha) for the 1000‐year return period flood discharge of 95 (similar to a 25‐year maximum mid‐future). The presence of embankments increases downstream sediment transport by more than 32% for all flood scenarios considered. Inclusion of sediment transport leads to a fivefold increase in predicted inundation area for a 25‐year maximum mid‐future flood compared to the no‐sediment case in the embanked channel. Changes in channel geometry due to sedimentation significantly reduce conveyance capacity increasing overtopping flood risk, particularly where the channel is sinuous or located on flat terrain. Our results indicate that sediment erosion in outer meanders may threaten embankment stability by promoting undercuts. It is recommended that sediment transport effects be factored into embankment design and floodplain planning.

Stability and Deformation Analysis of Embankment on Soft Clay

Soft clay generally poses a problem for civil engineers due to its high compressibility and low shear strength. Structures built on soft soil are subjected to excessive settlement and the settlement is attributed to the consolidation process. A large percentage of the settlement is accredited to a consolidation process that could persist for a long period, depending on the ability of the soil to dispel excess pore water. Prediction of the settlement of embankment is important for the design of the highway, to prevent excessive post-construction settlement which can lead to failure. Construction on soft clays has become more important and common in urban areas In this study, the time-settlement behavior of an embankment on soft clay predicted using analytical methods is compared with those predicted by Geo studio SIGMA/W software. Thus the magnitudes of final settlement using Terzaghi theory differ from the magnitudes of final settlement computed from SIGMA/W software by approximately ±10% difference. The differences could be due to the assumption properties such as Young’s modulus (E) and Poisson’s ratio (ν) in the SIGMA/W Geo studio, and the coefficient of compressibility considered in the analytical method. Moreover, this study presented the results of the stability analysis of the embankment on soft clay, and the performances of the barrier were analyzed. The limit equilibrium method (LEM) using Geo studio SLOPE/W software and hand calculations were used to calculate the factor of safety. The results showed that the calculated factors of safety obtained from Fellenius, Bishop, Janbu, and Morgenstern-Price methods using both ways are very similar, with an approximate difference of only ±10%.

Assessing the Settlement and Deformation of Pile-Supported Embankments Undergoing Groundwater-Level Fluctuations: An Experimental and Simulation Study

The intensification of extreme weather phenomena, ranging from torrential downpours to protracted dry spells, which trigger fluctuations at the groundwater level, poses a grave threat to the stability of embankments, giving rise to an array of concerns including cracking and differential settlement. Consequently, it is crucial to embark on research targeted at uncovering the settlement and deformation behaviors of pile-supported embankments amidst changes in water levels. In tackling this dilemma, a series of direct shear tests were carried out across a range of wet–dry cyclic conditions. The results confirmed that the occurrence of wet–dry cycles significantly impacted the resilience of silty clay. Additionally, it was observed that the erosion of cohesion and the angle of internal friction initially diminished sharply, subsequently leveling off, with the first wet–dry cycle exerting the most substantial influence on soil strength. Employing a holistic pile-supported embankment model, simulations revealed that variations in the groundwater level, fluctuations therein, varying descent rates, and periodic shifts in the groundwater level could all prompt alterations in soil settlement between embankment piles and could augment the peak tensile stress applied to geogrids. In summary, the orthogonal experimental method was utilized, indicating that, in terms of impacting embankment settlement under periodic water-level changes, the factors ranked in descending order were the following: pile spacing, pile length, embankment height, and the height of the groundwater table.

Analytical solutions for the stability of stone column-supported and geosynthetic-reinforced embankment

Analytical solutions for the stability of stone column-supported and geosynthetic-reinforced embankment

Effect Evaluation of the Interaction Between the Atmosphere and the Soil on the Ngamakosso’S Embankment Stability, Talangaï, Brazzaville, Republic of Congo

Effect Evaluation of the Interaction Between the Atmosphere and the Soil on the Ngamakosso’S Embankment Stability, Talangaï, Brazzaville, Republic of Congo

Perbandingan Metode Kalibrasi Sistem Celup Dan Chamber Untuk Vibrating Wire Piezometer In Situ

Piezometers are geotechnical monitoring instruments commonly used to obtain pore water pressure or groundwater level values. The most popular piezometer is the electric type (vibrating wire). The way this type of piezometer works is that the pore water pressure acting on the diaphragm causes a change in voltage and resonance on the vibrating wire. From the resonance of the vibrating wire will issue a frequency that will be recorded by the reading unit. This change in water force will affect the magnitude of the frequency read in the reading unit. In addition, seepage patterns, possible piping zones, and the effectiveness of seepage control used can be evaluated with the help of this tool. Currently piezometers are widely used for Monitoring embankment stability and safety, Measuring water load behind retaining walls, Assessing soil consolidation, Measurement of uplift pressure acting on structural foundations, Verification of seepage patterns and models, Monitoring slope stability, Monitoring water levels for environmental control, Assessment of tidal influence, Pump testing. Due to the importance of these instruments and their high sensitivity, it is necessary to calibrate them before installation to ensure that the equipment functions properly and accurately. Some methods of conducting in-situ calibration that are often used are the dip method and the pressurized chamber or cell method. This study will compare the two methods to determine the accuracy of the calibration implementation that can be used as a consideration for the acceptance of instruments from certain manufacturers. Based on the research that has been done, calibration with the chamber method is more accurate and acceptable after analysis. Because in its implementation it can be more thorough and there is not much external disturbance as in the dip method calibration method carried out in lakes or reservoirs where there is a lot of external disturbance.

Numerical simulation on the effects of deteriorating crushed-rock interlayers on thermal stability of embankments in permafrost regions

The crushed-rock layer (CRL) in permafrost regions frequently deteriorates due to aeolian sand, snow accumulation as well as vibrations induced by traffic loads. This degradation can adversely affect the thermal performance of crushed-rock embankments (CREs), potentially causing deviations from their designed specifications. Therefore, it is imperative to thoroughly investigate the thermal stability of CREs under conditions of CRL degradation. By utilizing the crushed-rock interlayer embankment (CRIE) as a representative case, this study employs numerical simulations to analyze six instances of crushed-rock interlayer (CRI) deterioration, employing a mathematical model incorporating adjusted thermal parameters specific to the CRIE. In addition, a novel methodology for quantitatively analyzing temperature distributions within permafrost embankments is employed to assess the results. The findings indicate that all embankment cases lose their cooling capacity on the underlying permafrost prior to the 35th service year. Therefore, mitigating the rate of CRI degradation is essential to preserving the integrity of its underlying permafrost throughout the entire lifespan of the CRIE. The results of this study contribute to the advancement of a theoretical framework for the construction of CRIEs with significant safety margins in permafrost regions.

Comparison of Embankment Properties with Clay Core and Asphaltic Concrete Core

The development of a country is affected by various multifaceted factors, which are likely to generate the highest benefits. For example, developing water resources by constructing embankments to store water and for transportation must consider high resilience, particularly with the current challenges arising from climate change. Another factor that must be considered is the shortage of essential materials for embankment cores, such as clay, which is the primary material for constructing such cores. This study aims to analyze the stability of soil embankments between the change of materials, namely clay and asphaltic concrete, by varying the water level and increasing the embankment load. The result shows that the asphaltic concrete core exhibits a significantly higher stability than the clay core, such as its reduced water seepage and lower deformation. In the worst-case scenario, the asphalt concrete core has a thickness of 0.3 m and a seepage rate of 15.1 × 10−4 m3/day. Comparatively, the seepage rate of the clay core is approximately 10-times lower.

Slope Stability Analysis of Rockfill Embankments Considering Stress-Dependent Spatial Variability in Friction Angle of Granular Materials

Slope stability is a major safety concern of rockfill embankments. Since rockfills are incohesive materials, only friction angle is considered as a shear strength parameter in the slope stability analysis of rockfill embankments. Recently, it was found that confining pressure can significantly affect the mean value and variance of the friction angle of rockfills. Since the confining pressure spatially varies within a rockfill embankment, the effect of stress-dependent spatial variability in the friction angle of rockfills should be investigated for slope stability evaluation of rockfill embankments. In the framework of the Limit Equilibrium Method (LEM), an approach is proposed for the slope stability analysis of rockfill embankments considering the stress-dependent spatial variability in the friction angle. The safety factors of slope stability are computed with variable values of the friction angle at the bases of slices which are determined by the stress-dependent mean value and variance of the friction angle of rockfills. The slope stability of a homogeneous rockfill embankment is analyzed to illustrate the proposed approach, and a parametric analysis is carried out to explore the effect of variation in the parameters of the variance function of friction angle on slope stability. The illustrative example demonstrates that the stress-dependent spatial variability of friction angle along the slip surface is obvious and is affected by the location of the slip surface and the loading condition. The effects of the stress-dependent spatial variability of the friction angle on the slope stability of high rockfill embankments should be considered.

Seismic Performance Assessment for Serviceability of Geosynthetic Reinforced Embankments

Embankments in the field of civil engineering were historically not given much attention in terms of their ability to withstand seismic activity, as they were considered to be non-critical structures. However, in recent years, the seismic stability of embankments has gained increasing importance in the field of geotechnical engineering. This increased significance is due to the need to quickly restore functional infrastructure after earthquakes. The occurrence of lateral spreading, resulting from foundation liquefaction, is the primary factor leading to embankment distress in geotechnical engineering during seismic events. To address this issue, this study presents a novel approach that employs geosynthetic basal reinforcement. The research paper presents a technique that uses geosynthetic basal reinforcement to manage the lateral spreading of embankments both pre- and post-earthquakes, guaranteeing their ongoing effectiveness. The proposed approach utilizes a pseudo-static limit equilibrium method for determining the tensile load produced in the basal reinforcement. The serviceability criteria establish the maximum strain permitted in the basal reinforcement by imposing a restriction on the horizontal movement of the embankment toe. By taking into account the tensile load of the reinforcement and the maximum allowable strain, it is feasible to establish an appropriate geosynthetic reinforcement that considers various factors including tensile strength, strain, design life, installation, and durability impacts.

Experimental study on the small strain stiffness-strength of a fully weathered red mudstone

Assessing the stability of embankments during railway operation is paramount for ensuring safety of railway. However, directly measuring the strength of fill materials can be challenging when the railway is in use. A strong correlation has been observed between soil shear strength and small strain stiffness. By establishing a robust correlation between shear strength and small-strain stiffness in the laboratory, considering various of factors, and combining it with field measurement of in-situ soil small stiffness might be an effective way to this problem. This study focuses on a type of filling materials commonly used in southwestern parts of China for railway construction: fully weathered red mudstone (FWRM) and its lime-treated counterpart (LFWRM), as the objects. A series of triaxial and unconfined compression tests were conducted to examine the effects of water content, confined pressure, and lime treatment on the shear strength and small strain stiffness of FWRM and LFWRM. The results show that the strength and stiffness of FWRM significantly decrease with increasing water content, while LFWRM specimens demonstrate good resistance. All LFWRM specimens displayed a brittle shear behavior. Empirical correlation was established for FWRM and LFWRM. The relationship for LFWRM is water content independent, meanwhile for FWRM is strongly dependent upon whether soil is saturated or not. The ratio of small strain stiffness to strength (Emax /qmax) for FWRM decreases substantially after saturation, whereas it remains almost constant for LFWRM. The reduction in strength and stiffness can be attributed to the degradation of the soil fabric due to increasing water content, where the pore size distribution (PSD) of FWRM changes significantly with increasing water content due to aggregate swelling. However, for LFWRM, the PSD remains bi-modal, which is due to the cementation bonding observed between lime-treated aggregates that explains the stable structure and improved performance of LFWRM.

ANALISIS STABILITAS TIMBUNAN TANAH DENGAN PERKUATAN GEOTEXTILE MENGGUNAKAN SOFTWAREPLAXIS (Studi Kasus Pembangunan Jalur Ganda Antara Solo Balapan – Kadipiro - Kalioso)

This research aims to determine the stability of embankments without reinforcement and with reinforcement and the amount of settlement that occurs in accordance with the SNI geotechnical standard 8460 of 2017. The research location is in KM. 96 + 400 to 104 + 900 between Solo Balapan – Kadipiro – Kalioso. The analysis was carried out using Plaxis 2D Software version 8.6 without reinforcement, a safety factor value of 1.2 was obtained, where the result was below 1.5, which did not comply with the requirements of SNI 8460:2017 article 7.5.5. as well as a 30 day decline of 1,707 cm, a 100 day decline of 1.6 41cm and a 365 day decline of 1,691 cm. So it can be concluded that the embankment at that location is unstable. For this reason, additional geotextiles are added as reinforcement, after adding geotextiles. In the analysis of the embankment at KM 98 + 550 with the addition of embankment reinforced with geotextile, manual calculation results were obtained with a total of 5 layers of geotextile. The minimum geotextile length is 2.338 m and the stability of the bearing capacity is SF = 4.37 > 1.5. For embankment analysis at KM 98 + 550 after adding geotextile reinforcement. After adding alternative geotextile reinforcement, it was found that the safety factor value increased to 1.7, where this value was greater than 1.5 as indicated by SNI 8460: 2017 article 7.5.5, while the decrease at 30 days was 1,056 cm, the decrease at 100 days was 1,056 cm, and the decline in 365 days was 1,056 cm, so it can be concluded that the embankment at that location is considered stable.