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The stability of road embankments is a critical aspect of sustainable infrastructure. Soil with inadequate shear strength may result in slope failure, particularly when compounded by the impact of vehicle traffic and surface erosion caused by intense and prolonged rainfall. Traditional soil stabilization methods frequently involve synthetic materials, which may have adverse environmental impacts. The objective of this study is to explore the possibility of utilizing Vetiver grass roots for bio-reinforcement in order to improve the shear strength of soils in road embankments, offering an environmentally friendly solution for soil stabilization. Sixteen undisturbed soil samples were collected from two distinct locations on a road embankment, each with its own unique soil composition. Both unreinforced and bioreinforced samples were subjected to a series of direct shear tests. The bio-reinforced samples were collected three months after Vetiver grass was planted on the slopes of the Rasipuram bypass road embankment. Shear strength parameters such as cohesion and the angle of internal friction, were assessed and compared between unreinforced and bio-reinforced soils. The study revealed a substantial enhancement in the soil's shear strength attributed to bio-reinforcement. In Location 1, the bio-reinforced soil showed a 48 percent to 64 percent increase in shear strength across different normal stresses, averaging a 53 percent improvement. In Location 2, the enhancement varied between 34 percent and 115 percent, resulting in an average rise of 67 percent. The cohesion of bio-reinforced soil in Location 1 increased from 5.23 to 11.52 kilonewtons per square meter, while in Location 2, it rose from 10.56 to 24.52 kilonewtons per square meter. At Location 1, the angle of internal friction rose from 20.07 to 27.42 degrees, while at Location 2, it increased from 17.73 to 23.22 degrees. This study concludes that the use of Vetiver grass for bio-reinforcement leads to a substantial improvement in the shear strength of soils, thereby establishing it as a feasible and enduring approach for stabilizing road embankments. The improvements in cohesion and the angle of internal friction indicates that Vetiver grass can effectively increase soil stability, offering an eco-friendly alternative to traditional soil stabilization methods. The findings ensure a healthy soil and plant setting, emphasizing the significance of Vetiver grass in enhancing soil characteristics and firmness, and presenting an environmentally friendly approach for sustainable infrastructure advancement. This study provides backing for the wider implementation of bio-reinforcement in infrastructure endeavors, aiding in the achievement of targeted sustainable development objectives such as sustainable development goals 9 (Industry, Innovation, and Infrastructure) and sustainable development goals 15 (Life on Land).

Purpose. To treat the stability problem of the phosphate Kef Essennoun quarry in the mining field of Jebel Onk located in the Northeastern part of Algeria. Methodology. To achieve these objectives, we started by monitoring the unstable area, using two monitoring systems: control stations and inclinometer. We then carried out a digital assessment of the Northwestern edge stability of the quarry under the current operating conditions of exploitation. After that, we proposed a new operating plan for the reopening of the depot under the required security conditions. At the end, we carried out an assessment of the edge stability, as the work to reopen and develop the Kef Essennoun quarry progressed. Findings. The results show that, under the current operating conditions of exploitation, the Northwestern edge of the Kef Essennoun quarry is unstable (FS < 1). The backfilling of the pilot pit of the mine, lead to the assurance of the mine walls stability, by increasing the values of safety factors with a rate of more than 30 %. Originality. The backfilling of the pilot pit of the mine and the resumption of top-down mining exploitation will ensure the stability of the quarry during and after the operating exploitation mining. Practical value. The study of the stability of the embankments bleachers, the edges of the quarries and the facings of the slag heaps during the open pit mining of useful ores deposits is an essential step that must be done gradually according to the development of mining works to guarantee the safety of personnel, materials, reserves and the environment.

Embankments have an important impact on the safe operation of river projects, the stability of surrounding towns and the safety of people’s lives and property. This paper expounds the formation reason of badger hole and deeply analyzes the harm of badger hole to the embankment, and discusses the past treatment measures and improved grouting treatment method of the badger cave in combination with the governance situation of Gucheng River Bureau (hereinafter referred to as the “Gucheng Bureau”), aiming to provide reliable theoretical and practical references for ensuring the safety and stability of the embankments.

Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams.

Internal erosion is a complex phenomenon which represents one of the main risks to the safety of earthen hydraulic structures such as embankment dams, dikes or levees. Its occurrence may cause instability and failure of these structures with consequences that can be dramatic. The specific mode of erosion by suffusion is the one characterized by seepage flow-induced erosion, and the subsequent migration of the finest soil particles through the surrounding soil matrix mostly constituted of large grains. Such a phenomenon can lead to a modification of the initial microstructure and, hence, to a change in the physical, hydraulic and mechanical properties of the soil. A direct comparison of the mechanical behaviour of soil before and after erosion is often used to investigate the impact of internal erosion on soil strength (shear strength at peak and critical state) using triaxial tests. However, the obtained results are somehow contradictory, as for instance in Chang’s study (Chang and Zhang in Geotech Test J 34(6):579–589, 2011), where it is concluded that the drained strength of eroded soil decreases compared to non-eroded soil, while both Xiao and Shwiyhat (Geotech Test J 35(6):890–900, 2012) and Ke and Takahashi (Geotech Test J 37(2):347–364, 2014) have come to the opposite conclusion. A plausible explanation of these contradictions might be attributed to the rather heterogeneous nature of the suffusion process and to the way the coarse and fine grains are rearranged afterwards leading to a heterogeneous soil structure, a point that, for now, is not taken into account, nor even mentioned, in the existing analyses. In the present study, X-ray computed tomography (X-ray CT) is used to follow the microstructure evolution of a granular soil during a suffusion test, and, therefore, to capture the induced microstructural changes. The images obtained from X-ray CT reveal indeed that fine particles erosion is obviously not homogeneous, highlighting the existence of preferential flow paths that lead to a heterogeneous sample in terms of fine particles, void ratio and inter-granular void ratio distribution.

Stiffened deep mixed (SDM) piles can be classified into three types based on the relative lengths of the core pile and the outer DM pile: the length of the core pile is shorter than, equal to, or longer than that of the outer DM pile. Limited research has been undertaken to investigate the performance of embankments supported by various types of SDM piles over soft soil. This study carried out a series of model tests to investigate the stability of embankment over soft clay improved by different types of SDM piles. The test results indicated that the improvement factors for embankment stability were 1.37, 1.87, and 1.75 for the tests with short-core, equal-core and long-core SDM piles, respectively. Significant vertical stress was concentrated onto the core pile due to its high stiffness, while the outer DM pile yielded earlier. Under the embankment crest, SDM piles generally failed by compression, while the short-core SDM pile exhibited bulging beneath the core pile tips, and the long-core SDM pile fractured at the unwrapped section. The SDM piles under the embankment slope mainly bore bending moments, and the type of SDM piles affected the bending pattern. The stability of SDM pile-supported embankments can be reasonably evaluated by considering the resisting moment of the piles due to lateral force. The position parameter of equivalent lateral force in an SDM pile-supported embankment ranges from 1/4 to 2/5.

Existing reliability analyses of embankment slopes usually considered the spatial variabilities of shear strength parameters and saturated hydraulic conductivity separately. Additionally, the variability in the soil–water characteristic curve (SWCC) was ignored. A non-intrusive approach is proposed for reliability analyses of unsaturated embankment slopes under four different cases on a steady-state seepage analysis. The spatial variabilities of hydraulic parameters (including fitting parameters, a and n, of SWCC and saturated hydraulic conductivity) and shear strength parameters are accounted for simultaneously. To illustrate the proposed approach, a hypothetical embankment under unsaturated seepage is investigated. The soil parameters of the embankment and foundation are modeled as lognormal random fields and lognormal random variables, respectively, to take into account the inherent uncertainties. Parametric sensitivity studies are then performed to account explicitly for the influence of the spatial variation of hydraulic parameters on the reliability of embankment slope stability. The proposed approach can act as a practical and rigorous tool for estimating the reliability of embankment slopes with small levels of probability of failure (i.e., 10−4–10−3). An interesting finding that the probability of failure of the unsaturated embankment slope decreases with the variability of the fitting parameter n of SWCC is observed and explained.

Floodplain 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 m3/s${\\mathrm{m}}^{3}/\\mathrm{s}$and by 15% (from 28.8 to 24.4 ha) for the 1000‐year return period flood discharge of 95 m3/s${\\mathrm{m}}^{3}\\mathrm{/}\\mathrm{s}$(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. Plain Language Summary Our research explores the impact of flood protection embankments being constructed along the Nakkhu River in the Kathmandu Valley, Nepal, in a region that is experiencing rapid urban growth. Using advanced computer simulations, we study how these embankments influence the erosion and deposition of sediment in the river, and hence impact flood risk. Our findings indicate that the construction of embankments increases sediment transport, and alters the geometry of the river increasing downstream flood risk during extreme flood events. This is particularly the case for embankments designed to follow natural, meandering river courses. We recommend incorporating sediment transport analysis into the planning and design of embankments and developments in floodplain areas to reduce the risk of flooding. Our study indicates that embankment construction by itself may not always be a sustainable long‐term flood‐protection measure for rivers carrying high sediment loads. Key Points Inclusion of sediment processes is very important in predicting the effect of embankments on river flood risk For the embanked Nakkhu, predicted inundation is fivefold larger for 25‐year maximum mid‐future event when sediment transport is included Sedimentation reduces channel capacity for flat terrain and large meanders; erosion at outer meanders threatens Nakkhu embankment stability

This study examines the stabilization of road embankments on soft soil in the Bts Road Section, Toli Toli City – Silondou, where road subsidence and flooding occur due to the soft peat soil and the area’s location in a watershed. To address these issues, the subgrade was improved using geotextile reinforcement with phased construction. The study aims to evaluate the safety factor of the embankments and the extent of soil consolidation settlement, using both the Plaxis V20 2D program and manual CPTu data interpretation. Results show minimal differences between the two methods in achieving 95% consolidation, with settlement differences of 3 cm with geotextile and 4 cm without. The time to reach this consolidation differed by up to 12 days. At 3, 6, and 12 months, settlement differences were 2 cm, 7 cm, and 1 cm, respectively. The safety factor for embankments with geotextile reinforcement was significantly higher, with changes of 38.70% at console stage 1, 29.39% at stage 2, 14.26% at preload, and 13.78% at U-95%. These results demonstrate that geotextile reinforcement provides effective stabilization for road embankments on soft soil.

Concrete columns are used to support embankments built on soft soils. Use of three groups of centrifuge model tests, this study exhibited the global performance of embankments supported by plain concrete columns and reinforced concrete columns. The objective of the centrifuge tests was to reveal the failure mechanism and the contribution of the reinforced concrete columns to embankment stability. In comparison with plain concrete columns, use of reinforced concrete columns alleviated the release and transfer of stress in the ruptured concrete matrix, thereby avoiding continuous failure, which improved the overall stability of the embankment. Based on parametric analysis, Pareto multi-objective optimization method was proposed to determine the optimal column configuration design. The optimization results showed that placing reinforced concrete columns from the toe to the shoulder, combined with the installation of plain concrete columns near the embankment’s centerline, not only satisfies the stability requirement of the embankment, but also minimizes construction costs and resource usage. Reinforced concrete columns which positioned of Rows 1–4 was suggested in this study.