Embankment Slope Research Articles

Апробация методики сдвиговых испытаний геосинтетического композита «КАПЛАМ»

Purpose: to investigate the effect of different test methods on the shear properties of geomaterials and to determine the test method that provides the most consistent shear strength results. Demonstrate the need to include shear test methods for geosynthetic materials in state standards. Determination of interaction properties of geosynthetic composite “KAPLAM” with soil. Methods: a 300×375 mm shear machine was used to perform shear tests at the soil-geomaterial interface with normal loads ranging from 100 to 500 kPa. These tests were performed according to the American standard ASTM D5321. Results: the relationships obtained from the tests allow the identification of the test methodology that produces the most significant shear strength results and an understanding of the fundamental mechanisms underlying the observed shear strength. The need for further investigation of this methodology on other geosynthetics is identified. Practical relevance: overall, these results have important implications for the design of railway embankment slopes, ISDS lining systems and shear strength testing. The tests provide better modelling of field conditions and a more accurate representation of the shear strength of composite materials.

Performance and reinforcement of air-cooled embankments traversing degrading permafrost of the Qinghai-Tibet Plateau

The reliable operation of railway embankments traversing degrading permafrost regions is challenged by climate warming. This study examines performances of four main types of railway embankments on the Qinghai-Tibet Plateau in thermally stabilizing permafrost foundation over warm permafrost using numerical modelling and 10-year monitoring data. Then, a reinforcement measure that combines a thermal conductivity variable system (TCVS) was designed to improve the cooling capacity of the crushed-rock sloped embankment (CRSE) by countering the heat absorption of slopes during summers. A coupled thermal-fluid-solid model was built to simulate and assess the cooling performance and reinforcing capacity of the new design. Results show that the crushed-rock embankments can produce convection cooling on the permafrost subgrade but the performances vary with different structures. The CRSE has insufficient cooling capacity to withstand the underlying permafrost degradation in warm permafrost regions. The optimized CRSE that combines the TCVS can effectively cool the underlying warm permafrost and decrease the shady-sunny slope effect under a warming climate, and can be used as an effective reinforcement measure. This study confirms the application of air-cooled embankments in protecting permafrost subgrade and provides guidance for structural design of embankment traversing degrading permafrost.

Runoff and infiltration characteristics of rainfall and snowmelt water on a model embankment slope composed of sandy soil simulating vegetation works.

Runoff and infiltration characteristics of rainfall and snowmelt water on a model embankment slope composed of sandy soil simulating vegetation works.

Application of new technologies to enhance the stability of high embankment slopes

This study aims to investigate the stability problems of high road embankment slopes in the Republic of Moldova, revealing shortcomings of classical methods. The authors propose a solution by using the RG system, equipped with specialized vibration drilling equipment from "RTG RAMMTECHNIC Gmbh". The method provides for the creation of piles in deep boreholes using the vibrating d, filling the cavities with soil, with subsequent compaction of soil in stages. Experimental field and laboratory research has demonstrated the effectiveness of this method. The results showed significant improvements in soil properties: increased density, strength, and deformation characteristics. The proposed technology offers advantages such as: increased load-bearing capacity of the soil-pile massif, practically complete elimination of dynamic effects on the ground and structures located in close proximity to the construction site, reduced manual labor costs, and a decrease in the overall cost of the construction work. The study aimed the application of this method in Moldova's road construction, highlighting its potential to counteract slope deformations caused by the action of various factors of any nature. The authors suggest the need for further research for refine the methodology, assess economic feasibility, and perform stress-strain analysis using the Finite Element Method. The study was concluded by outlining plans for future research on embankment slopes stabilized by soil piles using the RG installation.

Reliability and landslide consequence analysis of long heterogeneous soil infrastructure slopes: A parallel computing investigation

Long infrastructures, like flood defense levees, built upon diverse soils, often face complex landslide failures. Risk assessments for such structures involve evaluating slope stability reliability and potential landslide consequences. Historically, embankment slope reliability and failure assessments focused on shorter sections due to computational limitations. This study, however, delves into a longer 3D soil slope section, 100 times the height, using the random finite element method to analyse the size or length effect. It conducts a parametric study varying the soil strength’s horizontal correlation length to understand slope failure initiation in heterogeneous soils. In contrast to prior work, this paper emphasises several facets: the realised factor of safety (FOS) distribution, quantification of discrete unstable zones and failures, and the size impact on the reliability and landslide consequences of long embankment slopes. Findings indicate the Weibull distribution better fits the realised FOS, aiding in predicting long embankment slope system reliability when combined with the weakest link theory. While multiple failures are possible for very long soil embankment slopes, observations suggest a greater likelihood of a single localised failure despite this potential.

Effectiveness and safety of coils plus glue in slope embankment technology versus coils plus sclerosant in embolization therapy for reflux-type pelvic venous disorders

ObjectiveThis study aimed to evaluate the effectiveness and safety of coils plus glue (CPG) in slope embankment technology vs coils plus sclerosant (CPS) in treating reflux-type pelvic venous disorders. MethodsThe analysis included patients diagnosed with reflux-type pelvic venous disorders who were treated with CPG or CPS from 2019 to 2021. The inclusion criteria were noncyclic pain lasting more than 6 months, atypical varicose, and transvaginal Doppler ultrasound (TVDUS) and computed tomographic venography confirming the diagnosis and excluding compression factors and other diseases. Propensity score matching was performed at a 1:1.1 ratio based on the following covariates: age, pregnancy, body mass index, pretreatment visual analog scale (VAS), dysmenorrhea, dyspareunia, urinary urgency, tenesmus, low back pain, vulvar varicosities, vaginal varicosities, and lower limb varices. The pain was relieved by embolizing the target lesions with different embolic materials. The efficacy and safety of the different embolization materials were compared by VAS and TVDUS examinations at 1, 3, 6, 12, 24, and 36 months. ResultsFrom a total of 495 patients, 88 patients were selected from the CPG group and 77 patients from the CPS group by propensity score matching. The patients were followed up for 36 months. The preoperative VAS score of the CPG group was 8 (range, 6-8), and the CPS score was 8 (range, 7-8; P = .64). The postembolization VAS score of the CPG group was 2.05 ± 0.37, and the CPS score was 2.14 ± 0.35 (P = .55). A total of 28 cases (16.9%) showed complications, most of which were transient pain after embolization. No serious complications such as coil embolization to the lungs occurred. In addition, the CPG group used fewer coils than the CPS group by using the slope embankment technique. The mean coil length of the CPG group was 77.18 ± 33.82 cm, and the CPS group was 105.29 ± 71 cm (P = .001). The CPG group had an average operative time of 44.49 ± 5.72 minutes, whereas the CPS group took 43.45 ± 4.18 minutes on average (P = .19). The radiation dose in the CPG group was 398.40 ± 76.16 mGy, and the radiation dose in the CPS group was 388 ± 44.23 mGy (P = .30). The median recurrence-free survival in the CPG group was 34.23 months (95% confidence interval, 33.2-35.2), and the median recurrence-free survival in the CPS group was 30.39 months (95% confidence interval, 28.2-32.6; log rank P = .018). ConclusionsEmbolization therapy for refluxing PeVD was safe and effective, and proficient use of slope embankment technique with CPG increased efficacy and reduced complications.

Internal erosion in granular soils with different microstructures under cyclically increased hydraulic gradients

Internal erosion is one of the leading causes of failures and accidents of embankment dams, dikes, and slopes. The hydraulic loading acts as the driving force to detach the soil particles, while the initial soil microstructure determines the susceptibility of particle loss. In engineering practices, the soil may be subjected to cyclic hydraulic loadings due to water level fluctuations by extreme weather of intensive rainfall and drought. Under such conditions, the soil internal erosion process will be different from that under the steady unidirectional seepage, which has not been fully studied and needs urgent investigation. Thus, in this study, the internal erosion process and hydraulic characteristics of soils with different microstructures were investigated by both laboratory seepage tests and the discrete element method (DEM) simulation. The results indicate that the soil with a higher fine content was more structurally stable, and required a larger hydraulic gradient for erosion initiation. Once the internal erosion occurred, the particle loss and the soil hydraulic conductivity increased with increasing fine content. Additionally, when the applied hydraulic gradient was essentially the same, the soil experienced a server erosion under the cyclically than monotonically increased hydraulic gradients, and the amount of eroded soils increased with the increasing gradient amplitude. The results of this study will expand our understanding of the physical mechanism and hydraulic behaviors of soils subjected to cyclically increased hydraulic gradients and with different microstrures.

The Influence of Asphalt Concrete Underlayment on Slope Stability of the Ballasted High-speed Railways

In recent years, a hot mix asphalt layer, known as an underlayment, has been replacing granular sub-ballast in high-speed and heavy haul tracks, aiming to overcome the limitations of traditional ballasted railways. However, there is a lack of literature regarding the impact of this layer on the slope stability of railway embankments. Ensuring the safety of trains and track availability requires a thorough understanding of embankment slope stability. Hence, this study examined the influence of the underlayment. layer on slope stability in ballasted high-speed railway embankments. Using Slope/W software, twelve embankment models with 2H:1V and 1.5H:1V slopes were analyzed. Half the number of the models were traditional ballasted, while the others incorporated the underlayment layer. Different heights (3, 6, and 8m) were simulated to evaluate the effect on slope stability for both slope levels and track cross-sections. The analysis focused on gravitational force and neglected the increase in pore water pressure. Safety factors for slope slipping surface were used to quantify stability. The findings revealed that the underlayment layer enhances slope stability by 8% to 31% in high-speed railway embankments. However, the degree of improvement decreases with increasing embankment height, and steeper slopes benefit more from the underlayment layer compared to gentler slopes. While these results are promising, further research is needed to investigate the impact of varying pore water pressure on asphaltic tracks.

Seismic fragility assessment of embankment: A displacement-based approach using dynamic finite element model analysis

Abstract The assessment of seismic fragility of highway embankments is a key component of seismic risk modeling for traffic infrastructure. This study examines the seismic fragility of an embankment using advanced finite element dynamic analysis, contrasting findings with prior research to validate results. Based on established methodologies, an incremental dynamic analysis (IDA) was executed, with the Probabilistic Seismic Demand Analysis (PSDA) for the development of fragility curves. A comparative study was conducted between two modeling methods; one employing finite difference (FD) method and other employing finite element (FE)method. The analysis revealed that, selection of inputs like the nature of earthquake time history and number of records selected along with the analysis method influences the seismic fragility assessment of embankments. The choice between finite difference and finite element methods can yield differing results, with FD, being grid-based, can face challenges with complex geometries and boundary conditions, on the other hand, FE’s mesh-based approach offers flexibility in modeling intricate domains, handles complex boundary conditions more adeptly, and provides a more continuous representation of material behavior. A distinct dynamic stability test based on Newmark sliding block principles showed the embankment slope’s inherent resilience, with no permanent deformation, underscoring the requirement for further research.

Long-term characteristics of a stabilized expansive clay exposed to environmental-driven processes

Understanding the impact of climatic conditions on the long-term performances of soils stabilized with lime and cement is of crucial importance. Most of the available studies on durability solely rely on laboratory investigations to assess the effects of exposure to environmental-driven processes such as wetting and drying, leaching, etc. In this context, a research embankment built in 2010 with an expansive soil stabilized with 4% quicklime and a mix of 2% quicklime and 3% cement was sampled in 2021. A comprehensive experimental campaign was conducted using these samples to evaluate the performance of materials 11 years after the construction of the structure. The studies were completed by microstructural and physico-chemical investigations to understand the mechanisms that might explain changes in performance over time.The analysis of the hydro-mechanical properties of the soil sampled between the edge and the interior of the embankment was first performed. The results indicated that the material taken near the surface had a mechanical behavior equivalent to the untreated soil, demonstrating a total loss of the benefit brought by lime/cement addition. Towards the internal part of the embankment, the mechanical performance progressively increased. Physico-chemical investigations showed that on the edge of the backfill significant part of the calcium was leached 11 years after the construction. This was associated to a drop of pH, and to the formation of calcite. The microstructure was also significantly altered on the edge of the embankment compared to the internal part of the structure. Based on these results, a new mechanism of soil deterioration driven by climatic conditions was proposed. Water circulation and carbonation, associated to a significant reorganization of the microstructure were identified as the main phenomena responsible for the degradation of the treatment effects. This study showed that embankment slopes built with lime and cement stabilized expansive clay must be protected from weather-driven processes to limit any associated degradation.

Prediction of Railway Embankment Slope Hydromechanical Properties under Bidirectional Water Level Fluctuations

Prediction of Railway Embankment Slope Hydromechanical Properties under Bidirectional Water Level Fluctuations

The effect of the impact of the transport load on the strength and deformability of the soil base of the road structure

The article presents the results of determining the strength and deformation characteristics of the soils of the roadbed. Models of road structures located on a weak soil base are also considered, with the justification of design schemes reflecting the basic physical conditions of the structure. The strength of weak soils under the influence of vibration loads depends on their variety and porosity. The higher the density of the soil, the higher its dynamic stability and the greater the values of vibration accelerations, which cause a decrease in its strength. When comparing the calculated data of the dynamic deflection of a weak soil base with experimental data, it was found that the discrepancy in quantitative values does not exceed 10 %, which is quite acceptable for this kind of research. The results obtained and the accepted models of road structures are recommended to be used in calculations of the stability of embankment slopes of the roadbed, as well as in calculations of the precipitation of the embankment body on weak foundations.

Cooling Performance of a Novel Ventilated Slope on Railbed in Permafrost Regions

ABSTRACTThe heat absorption of the railbed mainly originates from the embankment slope in permafrost regions. A novel ventilated slope (NVS) with a double‐layer convection channel is proposed and verified. By applying this method to the Qinghai–Tibet Railway (QTR), the annual average temperature at the 10 cm depth below the embankment slope surface under NVS was reduced by 4.95°C. The freezing index at the 10 cm depth of NVS was 1.78 times higher than that of the slope without any cooling approaches. The numerical simulation results showed that heat was accumulated for the conventional embankment, while heat was released from the railbed after the application of NVS. With the cooling effect of NVS, the 0°C isotherm would rise above the original natural ground surface in the 2nd year after the embankment construction. A low‐temperature region of −2°C would be observed in the underlying permafrost by the 10th year. The underlying permafrost would remain frozen in the 50th year. This study provides a novel method for protecting the underlying permafrost in permafrost regions.

Fragility assessment for the rainfall-induced embankments on silty soils

The fragility curve expresses the probability that an asset exceeds some serviceability state for a given level of environmental perturbation or other loadings. It is an important component in the quantitative risk analysis and resilience evaluation of infrastructure exposed to natural hazards. Incidences of over-settlement of embankments are increasingly reported due to more intense and longer-duration rainfall events. This paper develops fragility curves for the rainfall-induced embankment settlement. For this purpose, an embankment incorporating enhanced seepage and displacement analysis within unsaturated soil conditions is modelled based on a reported case history. A Monte Carlo simulation is used for rainfall infiltration and embankment deformation analysis under various rainfall scenarios. Probability values are obtained to achieve three levels of damage states in terms of road embankment settlement. The parametric analysis produces the exceedance probability curves for various rainfall intensities, saturated permeabilities and embankment slope angles. This work offers an efficient tool for assessing fragility to rainfall-induced excessive settlement of embankments.

Briefing: Intensive inland aquaculture ponds: challenges and research opportunities

This briefing presents an overview of inland aquaculture scenario that focuses on challenges of aquaculture farming, contaminant transport and the future of aqua farming in a broader perspective of environmental geotechnics. Un-engineered aquaculture practices are a cause of concern, and special attention is necessary in waste water management, cross-contamination with the adjacent environment, sludge–subsoil interaction, pond embankment slope failure, leachate migration into the vadose zone, geoenvironmental remediation strategies and geotechnical engineering aspects of engineered pond construction.

A Study on the Factors Influencing High Backfill Slope Reinforced with Anti-Slide Piles under Static Load Based on Numerical Simulation

Based on a real engineering case, this study employs the MIDAS finite element software to model the reinforced high embankment slope using anti-sliding piles. The accuracy of the finite element method is verified by comparing calculated outcomes with field monitoring data. Expanding on this foundation, an analysis of factors influencing the reinforced high embankment slope is undertaken to scrutinize the impact of diverse elements on the slope and ascertain the optimal reinforcement strategy. The results reveal the following: The principal displacement observed in the high embankment slope is a vertical settlement, which escalates with the backfill height. Notably, the highest settlement does not manifest at the summit of the initial slope; instead, it emerges close to the summits of the subsequent two slopes. However, the maximum horizontal displacement at the slope’s zenith diminishes as the fill height increases—a trend that aligns with both field observations and finite element computations. The examination of the influence of anti-sliding pile reinforcement on the high embankment slope unveils that factors like the length, diameter, spacing, and positioning of the anti-sliding piles exert minor impacts on vertical settlement, while variations in the parameters of the anti-sliding piles significantly affect the slope’s horizontal displacement. When using anti-sliding piles to reinforce multi-level high embankment slopes, factoring in the extent of horizontal displacement variation and potential cost savings, the optimal parameters for the anti-sliding piles are a length of 15 m, a diameter of 1.5 m, and a spacing of 2.5 m, presenting the most effective combination to ensure superior slope stability and support.

Study on LOS to Vertical Deformation Conversion Model on Embankment Slopes Using Multi-Satellite SAR Interferometry

Slant range geometry plays a crucial role in interpreting synthetic aperture radar (SAR) observations, especially in converting line-of-sight (LOS) surface deformations to actual vertical subsidence. This paper proposes a new conversion model to retrieve vertical settlements of the embankment slopes using the geometrical parameters of the dam and the SAR sensor. The simulation results highlight the impact of slope foreshortening and heading direction of the satellite on deformation retrieval. Various SAR data with different resolutions and bands are used to analyze the model’s performance, revealing a high conformity of the model with practical conversion parameters exceeding 80% for TerraSAR-X and Cosmo-SkyMed data.

An improved analytical model for rainfall infiltration in embankment slope constructed with red-bed solid waste

Rainfall infiltration is one of the key triggering factors of landslide in embankment slope constructed with red-bed solid waste, so rainfall infiltration analytical model plays a critical role in the landslide prediction. However, the complexity of the red-bed solid waste slope’s components has not be considered by the conventional Green-Ampt infiltration model, which has also ignored the influence of the dynamic variation of unsaturated section in the wetted zone of slope under rainfall infiltration. This study proposed an improved rainfall infiltration analytical model for red-bed solid waste slope considering the properties of rock fragments and the dynamic development of saturated–unsaturated proportion in the wetted zone, and developed a solution program for the improved model. The proposed model was validated by comparing the rainfall infiltration experiment, finite element numerical simulation, and traditional Green-Ampt method. The proposed model was then applied to parameter sensitivity analyses to reveal the rainfall infiltration characteristics of red-bed solid waste slope. The results indicate that the rainfall infiltration model proposed in this work perform better to predict the rainfall infiltration process of red-bed solid waste slope, and it will lay the groundwork for more reliably utilizing the red-bed solid waste in transportation geotechnics.

Landslide Management for Batu Tulis – Cross Bogor – Sukabumi Station Double Lane Project at STA 5+550

In the implementation of the St. Batu Tulis – Lintas Bogor – Sukabumi STA 5+550 project, a significant challenge arose with the occurrence of an avalanche during construction, attributing landslides to substantial land subsidence caused by the destabilization of the slope's soil or rocks. This disruption significantly impacted construction planning, particularly in terms of cost considerations. This study conducted a comprehensive comparative analysis of the stability of the original embankment slope and slopes reinforced with gabions (measuring 2m x 1m x 0.5m), sheet piles (type W-400 A-1000), and bored piles (size D600). To evaluate the stability, it was imperative to determine the safety factor (SF) and slope deformation under applied loads. The Plaxis 8.6 program was employed for the analysis, incorporating all relevant soil parameter data. Safety factor values were calculated as 1.67 for the gabion-bored pile combination slope, 1.62 for the sheet pile-reinforced slope, and 1.63 for the bored pile-reinforced slope. Estimated costs for slope strengthening were as follows: IDR 3,525,789,199.92 for sheet piles, IDR 2,180,309,258.00 for bored pile-gabion combination, and IDR 6,689,603,822.00 for bored piles alone. The budget for slope reinforcement with gabions proved more economical by IDR 1,345,479,941.92 compared to sheet piles and IDR 4,509,294,564.00 compared to bored piles. The reinforcement type selection was based on a cost analysis, prioritizing lower expenses while ensuring construction feasibility. Gabions offer advantages such as economical prices, flexibility, and simple construction methods, but they have drawbacks, including susceptibility of galvanized coated wire to water conditions with high salt or acid content and requiring a wide area for construction due to their large size. Sheet pile reinforcement is resistant to corrosion, durable, and has good performance, but it is unsuitable for supporting very high soil due to the requirement of a large cross-sectional area and not suitable for use in rocky soils due to piling difficulties.

Exploring the Influence of Climate Change on Earthen Embankments with Expansive Soil

Climate change is known to cause alterations in weather patterns and disturb the natural equilibrium. Changes in climatic conditions lead to increased environmental stress on embankments, which can result in slope failures. Due to wetting–drying cycles, expansive clayey soil often swells and shrinks, and matric suction is a major factor that controls the behavior. Increased temperature accelerates soil evaporation and drying, which can cause desiccation cracks, while precipitation can rapidly reduce soil shear strength. Desiccated slopes on embankments built with such soils can cause surficial slope failures after intense precipitation. This study used slope stability analysis to quantify how climate-change-induced extreme weather affects embankments. Historic extreme climatic events were used as a baseline to estimate future extremes. CMIP6 provided historical and future climatic data for the study area. An embankment was numerically modeled to evaluate the effect on slope stability due to the precipitation change induced by climate change. Coupled hydro-mechanical finite element analyses used a two-dimensional transient unsaturated seepage model and a limit equilibrium slope stability model. The study found that extreme climatic interactions like precipitation and temperature due to climate change may reduce embankment slope safety. The reduction in the stability of the embankment due to increased precipitation resulting from different greenhouse gas emission scenarios was investigated. The use of unsaturated soil strength and variation of permeability with suction, along with the phase transition of these earthen embankments from near-dry to near-saturated, shows how unsaturated soil mechanics and the hydro-mechanical model can identify climate change issues on critical geotechnical infrastructure.