Landslide Research Articles

Analyzing MSW Landfill Failures: Stability and Reliability Evaluations from Five International Case Studies

This study investigates five cases of municipal solid waste (MSW) landfill slope failures in the USA, China, Sri Lanka, and Greece, with the aim of assessing the safety margins and reliability of these slopes. The stability and reliability of the landfill slopes were evaluated under both static and seismic loading conditions, using pre-failure geometries and geotechnical data, with analyses conducted in accordance with Eurocode 7, employing all three design approaches. Under static loading, the factors of safety were close to unity, and reliability indexes ranged from 1.0 to 2.8, both falling below the recommended values set by Eurocode. The landfill slopes failed to meet the stability criteria in Design Approaches 2 and 3, while in Design Approach 1, four out of five landfills met the criteria. Under seismic conditions, safety factors and reliability indexes were significantly lower than the prescribed criteria in all analyses. Sensitivity analyses revealed that in two cases, unit weight and friction angle were the dominant parameters, while cohesion was the dominant parameter in one case. The findings of this study underscore the importance of establishing minimum design requirements for MSW landfill slope stability to mitigate potential risks to public health and the environment.

Modeling the clogging process of leachate collection systems in municipal solid waste landfills: The role of temperature

The leachate collection system (LCS) is an important component of barrier systems in municipal solid waste (MSW) landfills. LCS Failure due to clogging could lead to leachate accumulation, potential soil and groundwater pollution and slope failure. LCS clogging is generally ascribed to particle deposition, biofilm growth, and calcium carbonate precipitation, while temperature strongly influences microbial activity and thus inevitably affects the clogging process of LCSs. However, the role of temperature in the process of clogging and leachate accumulation in LCSs remains unclear. The main objective of this study was to bridge this research gap by developing reasonable mathematical models and comprehensively analyzing this issue. The mathematical model involved leachate flow, solute migration, physical–chemical-biological clogging, and heat transfer processes. By conducting a series of numerical simulations, the temperature variation, clogging development, and corresponding leachate accumulation inside the system during long-term operation in both the geotextile and gravel layers were numerically analyzed and predicted. The results demonstrated that, in the gravel layer, due to the higher temperature, more thorough microbial substrate consumption led to higher production of carbonate ions and hence faster and more notable calcium carbonate precipitation. Overall, the bioactivity changes due to high temperatures could considerably accelerate the failure of LCS.

Centrifuge tests on the deformation law of pipelines crossing slopes with different water contents

The deformation law of pipelines crossing landslide areas is an important prerequisite for the scientific design of pipelines. Most current studies find it difficult to simulate the real stress and strain state of pipelines on site. This study conducted two centrifuge model tests to observe pipeline failure indicators (deformation, stress, strain) and slope failure indicators (crack width, soil pressure, landslide displacement) in response to changes in acceleration. The experimental findings align with the results obtained from numerical simulations. The findings indicate that slope failure with high moisture content is more serious. At a moisture content of 15%, the slope has a maximum displacement of 70 mm in close reach to the buried pipeline. The pipeline has a “bimodal distribution” of strain along its axial length. The largest amount of deformation occurs at a distance of L/4 from the center of the pipeline, and the deformation value is 9000 με. Moreover, the maximum deformation in the mid-span is 21 mm, which corresponds to the result accumulated from the numerical simulation. Thus, the pipeline needs to improve the disaster prevention capabilities at the mid-span and L/4 of the pipeline.

Soil Erosion Characteristics of the Agricultural Terrace Induced by Heavy Rainfalls on Chinese Loess Plateau: A Case Study

Terrace erosion has become increasingly pronounced due to the rising incidence of heavy rainfalls resulting from global climate change; however, the processes and mechanisms governing erosion of loess terraces during such events remain poorly understood. A field investigation was performed following a heavy rainfall event in the Tangjiahe Basin to examine the soil erosion characteristics of loess terraces subjected to heavy rainfall events. The results show that various types of erosion occurred on the terraced fields, including rill, gully, and scour hole in water erosion, and sink hole, collapse, and shallow landslide in gravity erosion. Rill erosion and shallow landslide erosion exhibited the highest frequency of occurrence on the new and old terraces, respectively. The erosion moduli of the gully, scour hole, and sink hole on the new terraces were 171.0%, 119.5%, and 308.7% greater than those on the old terraces, respectively. In contrast, lower moduli of collapse and landslide were observed on the new terraces in comparison to the old terraces, reflecting reductions of 34.2% and 23.4%, respectively. Furthermore, the modulus of water erosion (32,102 t/km2) was 4.5 times that of gravity erosion on the new terraces. Conversely, on the old terrace, the modulus of gravity erosion (8804.1 t/km2) exceeded that of water erosion by 14.5%. Gully erosion and collapse dominated the erosion processes, contributing 67.8% and 9.4% to soil erosion on the new terraces and 38.7% and 34.0%, respectively, on the old terraces. In the study area, the new terraces experienced significantly greater erosion (39,252 t/km2) compared to the old terraces (16,491 t/km2). Plastic film mulching, loose and bare ridges and walls, inclined terrace platforms, and high terrace walls, as well as the developing flow paths, might be the key factors promoting the severe erosion of the terraces during heavy rainfall. Improvements in terrace design, construction technologies, temporary protective measures, agricultural techniques, and management strategies could enhance the prevention of soil erosion on terraces during heavy rainfall events.

Causes and prevention of technogenic disasters resulting from slope failure

Causes and prevention of technogenic disasters resulting from slope failure

Landslide susceptibility assessment using novel hybridized methods based on the support vector regression

Landslide susceptibility assessment is a complex task due to the multitude of causative factors, spatial variability, data availability, modeling uncertainty, and validation issues. This study addresses these challenges by proposing two predictive models that hybridize support vector regression (SVR) with two evolutionary algorithms: grey wolf optimizer (GWO) and cuckoo search algorithm (CSA). These models were developed using an extensive geospatial database from northern Iran. Over the training phase, the basic predictive model, developed using SVR, was enhanced by incorporating the GWO and CSA algorithms, resulting in the development of two hybridized models: SVR-GWO and SVR-CSA. Over the validation phase, the performance and effectiveness of each hybridized model were compared to the standalone SVR using several metrics. Compared to the standalone SVR model, the hybridized models demonstrated significant improvement in generalization and predictive abilities. Despite non-significant difference between the performances of the SVR-GWO and SVR-CSA models, the SVR-GWO model demonstrated superior performance. This could be attributed to the GWO's capabilities, which included generating a variety of solutions, demonstrating robustness against noise and outliers, achieving faster convergence speed, and effectively interacting with SVR. This study highlighted that utilizing intelligence hybridized models can significantly enhance the balance between accuracy, robustness, and objectives compared to single models. This finding holds significant implications for ecological engineers tasked with designing and implementing solutions to mitigate the impact of shallow landslides on the environment and human communities. The predictive models developed in this study serve as valuable tools for these engineers, enabling them to identify high-risk areas and implement preventative measures. This interdisciplinary approach, which combines machine learning, optimization algorithms, and ecological engineering, highlights the potential for pioneering solutions in tackling complex environmental challenges, thereby standing as a testament to the power of innovation in driving progress in landslide susceptibility assessment.

Slope stability assessment and landslide susceptibility mapping in the Lesser Himalaya, Mussoorie, Uttarakhand

The present study aims to assess slope stability and landslide susceptibility mapping of road-cut slopes along Mussoorie road in the Lesser Himalayan region. A total of 18 suspected unstable slope sites were selected for the investigation, and performed geo-mechanical classification techniques, including Rock Mass Rating (RMR), Slope Mass Rating (SMR), Geological Strength Index (GSI), and kinematic analysis. For the Landslide susceptibility mapping, the Frequency Ratio (FR) method was employed using the weightage of various causative factors which includes slope, aspect, curvature, elevation, distance from streams, distance from lineaments, lithology, and rainfall. The finding indicates that out of 18 selected slopes, 4 slopes are bad slope or unstable, which includes slope 3,4 and 6 in the lower part of the Mussoorie area near Jharipani, while slope 10 near Hathi Paon-Mussoorie Road is also unstable. The slopes around Junu waterfall are stable. Partially unstable slopes may vulnerable to slope failure in the future due to heavy rainfall and unstructured construction. Additionally, the Area Under Curve (AUC) and predictive rate curve values are 61% and 78% respectively, indicating acceptable overall accuracy. This study highlights the landslide issues in Mussoorie region due to rapid urbanization & climate change and demonstrates the effectiveness of the employed methods for future risk analysis.

Geotechnical Evaluation of Landslide in Nanggerang Village

Landslides are significant geological events that can cause extensive damage to infrastructure, disrupt communities, and pose serious safety hazards. Understanding the mechanisms behind slope failures is crucial for effective risk mitigation and the development of engineering solutions to improve slope stability. According to data from the National Disaster Management Agency (BNPB), Indonesia experienced 83 landslide events from January to February 2024. A notable landslide occurred in Nanggerang Village, Sukasari Sub-district, Sumedang Regency, West Java Province, on February 3, 2024. This landslide happened in a terraced rice field area following heavy rainfall earlier in the day. This study focuses on evaluating the failed slope to understand its condition just before failure and the material properties that influence the landslide event. The research methodology includes field data collection, soil testing, and slope stability analysis using the Limit Equilibrium Method (LEM) with a probabilistic approach via Slide 2 software. The analysis revealed that the failed slope had an average safety factor (FS) of 0.968 and a landslide probability of 58.897%. Sensitivity analysis showed that the cohesion parameter in the soil layer (CWZ) significantly impacts the safety factor of the slope. The study concludes that the reduction in soil cohesion and internal friction angle due to excessive moisture was the primary cause of the landslide, and the cohesion parameter of the soil layer is the most sensitive factor affecting slope stability.

DESIGNING A GEOMETRY OF LOWWALL SLOPE IN COAL MINING USING THE LIMIT-EQUILIBRIUM METHOD AT THE WORKING AREA OF PT. PETROSEA TBK, TARAKAN BASIN, NORTH KALIMANTAN, INDONESIA

Mining, which involves extracting minerals and utilizing natural resources, requires careful planning to ensure feasibility and safety. A critical aspect of open pit mine design is slope stability, influenced by geological characteristics, slope topography, and groundwater conditions. Slope stability analysis, using methods such as the Limit Equilibrium Method (LEM), which has been popular for decades for its convenience, evaluates the potential for slope failure and provides geometric slope design recommendations to reduce risk, improve operational efficiency, and ensure environmental sustainability. The research was conducted at PT Petrosea Tbk, with the mine site in Sebakis Village, Sebuku Subdistrict, Nunukan Regency, North Kalimantan, PT X region. The research object is a lowwall slope that requires stability analysis to prevent landslides. The slope safety criteria are based on the Minister of Energy and Mineral Resources Decree No. 1827 K/30/MEM/2018 guidelines, specifically 1.1. To perform the analysis, laboratory test data is required, including rock physical property tests and rock shear strength tests to obtain material property values. This data was then analysed using Rocscience Slide2 software by comparing three methods: Bishop, Janbu, and Morgenstern-Price. The analysis was conducted based on the actual conditions of each slope cut geometry. If the obtained safety factor does not meet the criteria of the Minister of Energy and Mineral Resources Decree No. 1827 K/30/MEM/2018, then designing a geometry of lowwall slope is required. The geometric slope design used on the lowwall slope includes creating benches to flatten the slope level, and installing drain holes to decrease the ground water level.

Focal mechanics and disaster characteristics of the 2024 M 7.6 Noto Peninsula Earthquake, Japan

On January 1, 2024, a devastating M 7.6 earthquake struck the Noto Peninsula, Ishikawa Prefecture, Japan, resulting in significant casualties and property damage. Utilizing information from the first six days after the earthquake, this article analyzes the seismic source characteristics, disaster situation, and emergency response of this earthquake. The results show: 1) The earthquake rupture was of the thrust type, with aftershock distribution showing a north-east-oriented belt-like feature of 150 km. 2) Global Navigation Satellite System (GNSS) and Interferometric synthetic aperture radar (InSAR), observations detected significant westward to north-westward co-seismic displacement near the epicenter, with the maximum horizontal displacement reaching 1.2 m and the vertical uplift displacement reaching 4 m. A two-segment fault inversion model fits the observational data well. 3) Near the epicenter, large Peak Ground Velocity (PGV) and Peak Ground Acceleration (PGA) were observed, with the maxima reaching 145 cm/s and 2681 gal, respectively, and the intensity reached the highest level 7 on the Japanese (Japan Meteorological Agency, JMA) intensity standard, which is higher than level 10 of the United States Geological Survey (USGS) Modified Mercalli Intensity (MMI) standard. 4) The observation of the very rare multiple strong pulse-like ground motion (PLGM) waveform poses a topic worthy of research in the field of earthquake engineering. 5) As of January 7, the earthquake had left 128 deaths and 560 injuries in Ishikawa Prefecture, with 1305 buildings completely or partially destroyed, and had triggered a chain of disasters including tsunamis, fires, slope failures, and road damage. Finally, this paper summarizes the emergency rescue, information dissemination, and other disaster response and management measures taken in response to this earthquake. This work provides a reference case for carrying out effective responses, and offers lessons for handling similar events in the future.

Slope stability modeling using limit equilibrium and finite element methods: A case study of the Adama City, Northern Main Ethiopian Rift

Slope failure is a prominent and recurring geohazard in numerous parts of Ethiopia, including Adama City, which is located in the Northern Main Ethiopian Rift (NMER). The city is surrounded by two ridges oriented in the NNE-SSW direction, which are susceptible to slope instability. Thus, this study is aimed at modeling slope stability along these two ridges using Finite Element Method (FEM) and Limit Equilibrium Method (LEM). The modeling was carried out on slopes of multifaceted geometry composed of eluvium soil, pumice, and moderately to highly-weathered ignimbrites. Critical slope sections were identified using satellite imagery and field manifestations such as slope toe condition and slope face tilting. Their geometries were then inferred from detailed geological cross-sections based on field data. Input parameters for the modeling, such as cohesion, friction angle, and elastic modulus, were calculated via Back Analysis using the Hoek-Brown criterion while unit weight and Poisson ratio were determined from empirical equations. For soil formations, the parameters were determined via standard laboratory experiments. The modeling was then carried out under different conditions, including dry, saturated, static, and dynamic conditions. Results from both LEM and FEM models revealed that three of the four analyzed slope segments were unstable under dynamic and saturated conditions, highlighting the influence and importance of precipitation and seismicity as triggering variables. Results from both methods tend to agree when the critical slip surface passes through a single geological material in both models. However, notable differences arise when the slip surface involves multiple geological materials. Under such conditions, LEM tends to yield higher FOS values compared to FEM. The results also showed that all unstable slopes were associated with the NNE-SSW striking fault of the study area, as inferred from failure surfaces generated from both models and field data. The study concluded that unstable slopes pose a serious risk to nearby residents and infrastructure, and as a remedy, it designed and recommended coupled benching and slope flattening.

Submarine canyon development controlled by slope failure and oceanographic process interactions

The southeastern Australian margin hosts a series of submarine canyons. Although the origin and evolution of canyons within the northwestern segment of the margin is relatively well studied, their quantitative morphology, interaction with longshore drift currents and slope failure remain poorly understood in the southeastern region. In this study, high-resolution bathymetry and 3D seismic reflection datasets revealed five main submarine canyons present in the central offshore Otway Basin. The canyons have V-shaped, evolving to U-shaped morphology downslope with sedimentary infill characterized by medium–high amplitudes, recognizable stratal pattern and localized chaotic seismic reflections. Analysis reveals these canyons were initiated by retrogressive slope failure on the continental slope, that once the shelf edge was reached and subsequently incised, development of the canyon heads was influenced by the shelf parallel Zeehan Current, active on the continental shelf of the region. The heads of the shelf-incised canyons preferentially migrate northwestward and were infilled by laterally accreting sedimentary packages characterized by southeast dipping seismic reflections. These indicate an early erosive phase followed by a period of deposition, a result of the prevalent eastward flowing Zeehan Current. These results have important implications for understanding of the mechanisms that control initiation and development of submarine canyons, and their morphology, both offshore southeastern Australia, and similar settings on continental margins worldwide.

Rock slope stability analysis of a limestone quarry in a case study of a National Cement Factory in Eastern Ethiopia

Rock slope failures pose significant challenges in geotechnical engineering due to the intricate nature of rock masses, discontinuities, and various destabilizing factors during and after excavation. In mining industries, such as national cement factories, multi-benched excavation systems are commonly used for quarrying. However, cut slopes are often designed with steep angles to maximize economic benefits, inadvertently neglecting critical slope stability issues. This oversight can lead to slope instability, endangering human lives and property. This study focuses on analyzing the stability of existing quarry cut slopes, estimating their final depth, and conducting a parametric study of geometric profiles including bench height, width, face angle, and rump width. Kinematic analysis helps identify potential failure modes. The results reveal that the existing quarry cut slope is prone to toppling, wedge failure, and planar failure with probabilities of 42.68%, 19.53%, and 14.23%, respectively. Numerical modeling using the finite element method (Phase2 8.0 software) was performed under both static and dynamic loading conditions. The shear reduction factor (SRF) of the existing quarry cut slope was 1.01 under static loading and 0.86 under dynamic loading. Similarly, for the estimated depth, the SRF was 0.82 under static loading and 0.7 under dynamic loading. These values indicate that the slope stability falls significantly below the minimum acceptable SRF, rendering it unstable. The parametric study highlights the face angle of the bench as the most influential parameter in slope stability. By adjusting the bench face angle from 90° to 75°, 70°, and 65°, the SRF increased by 31.6%, 35.4%, and 37.9%, respectively. Among these, a 70° bench face angle is recommended for optimal stability with a SRF of 1.27 under static loading and 1.18 under dynamic loading.

Numerical Investigation of Bedding Rock Slope Potential Failure Modes and Triggering Factors: A Case Study of a Bridge Anchorage Excavated Foundation Pit Slope

The analysis of slope failure modes is essential for understanding slope stability. This study investigated the failure modes and triggering factors of a rock slope using the limit equilibrium method, finite differences method, and exploratory factor analysis. First, the limit equilibrium method was used to identify potential sliding surfaces. Then, the finite differences method was employed to study deformation and failure features in a slope. Stability factors were calculated considering specific conditions such as rainfall, prestressing loss, and earthquakes using the strength reduction method. Finally, exploratory factor analysis was utilized to identify the triggering factors of each failure mode. The results revealed that failure modes were categorized into two types based on the positions of the sliding surface. The main triggering factors for Failure Mode 1 were rainfall and prestress loss, while for Failure Mode 2 they were earthquake loading and prestress loss. This study offers a comprehensive exploration of potential failure modes and their triggering factors from mechanical and statistical perspectives, enriching our understanding of potential failure modes in rock slopes.

Forecasting open-pit slope runout distances

Geotechnical engineers are routinely tasked with advising suitable stand-off distances below high-risk sections of slopes in open-pit mines that are identified to have potential to deform or collapse. Accurate prediction of failed material runout can mean the difference between continuous safe mining and unwanted high-potential incidents that result in loss of production, equipment damage, injury, or loss of life. This paper updates previous empirical relationships presented by the authors for estimating the volume and runout distance of excavated slope failures, in an open-pit mine operation, using slope geometry as the primary predictor. Cases are sourced from varying slope geometries (fall heights up to 385 m, slope angles up to 80°) and a range of commodities (iron ore, coal, nickel, gold, copper, boron, and limestone), excavated in sedimentary, banded-sedimentary, epithermal, and copper-porphyry deposits, across all six inhabited continents. Analysis of these cases identified positive correlations between slope height and runout distance, and slope height and failed material volume. In general, negative correlations were identified between Fahrböschung angle and slope height, and Fahrböschung angle and failed material volume; however, significant scatter is observed in these datasets. A definitive relationship could not be derived comparing Fahrböschung angle with failed material runout. Slope angle was also found to be a poor indicator of runout. Of the parameters analysed, slope height (i.e., fall height) was found to be the simplest and best predictor of runout distance. This paper presents new charts for predicting failed material runout distance for rock slopes. Relationships are defined for structurally and rock-mass driven slope failure mechanisms at average, 75%, and 95% prediction intervals.

Impact of discontinuity data acquisition methods on rockfall susceptibility assessment using high-resolution 3D point cloud

This research evaluates the influence of various discontinuity data acquisition methods on three-dimensional rockfall susceptibility assessments, employing a high-resolution 3D point cloud of the Špičunak rock slope in Croatia. Discontinuity mapping was conducted utilising manual and semi-automated methods. Manual mapping was done in open-source software CloudCompare, while semi-automated mapping was done using Discontinuity Set Extractor and two CloudCompare plug-ins, qFacet Fast Marching and qFacet Kd-Tree algorithm. Significant differences were observed between the methods in terms of the number of identified discontinuity planes, sets, mean orientation values, and weighted densities associated with specific sets. Based on the mapping results, three-dimensional rockfall susceptibility maps were generated. The 3D rockfall susceptibility assessment employed a Kinematic Hazard Index (KHI) for planar, wedge, and flexural toppling failure mechanisms, which determines the percentage of discontinuity planes that meet the geometrical conditions specific to each type of failure. The findings underscore that the mapping results greatly affect the 3D rockfall susceptibility assessment, impacting the identification of potential rockfall source areas. The study emphasizes the importance of integrating manual and semi-automated mapping for reliable 3D rockfall susceptibility assessment. Additionally, this study evaluated the effect of varying the number of discontinuity orientation input data on rockfall susceptibility by comparing nine scenarios, each involving a reduction in the number of discontinuity orientation data. The results indicate that accurate discontinuity mapping is more critical than the sheer number of mapped discontinuities for reliable rockfall susceptibility assessment. Therefore, prioritizing the precise determination of discontinuity set numbers and their associated weighted densities is essential for reliable susceptibility evaluations.

Analysis of water inrush of a deep excavation triggered by river bank failure and its reconstruction

Many deep excavation projects are adjacent to river, and hence face the seepage risk. In this study, a through-wall seepage failure of a foundation pit adjacent to river is investigated. It is found that, the accident was initiated by the breakage of revetment along the construction joint and cracks of rubble stone masonry, which further caused the slope failure of river bank and the subsequent seepage of river water through the cold joint of waterproof curtain. The remedial works including construction of cofferdam in the river, backfill outside the foundation pit, reinforcement of cold joint, backfill inside the foundation pit, controllable dewatering outside the foundation pit and axial force adjustment of struts are designed. The monitoring results indicate effective implementation of the remedial works and the following successful reconstruction of the project. A summary of reported seepage failure cases adjacent to river is finally made to provide suggestions for the design and construction of future similar deep excavation projects.

More Catastrophic Flow Events may Follow the Chamoli Rock and Ice Avalanche under Climate Change

More Catastrophic Flow Events may Follow the Chamoli Rock and Ice Avalanche under Climate Change

More mass wasting activities reported in Sedongpu gully of Tibetan Plateau, China

Although the increase in the frequency of mass wasting events in the Sedongpu gully in recent years indicates that the Sedongpu gully has entered an intense mass wasting period, the current literature focuses only on ice‒rock avalanche events and lacks comprehensive knowledge of Sedongpu gully activity. To clarify the spatiotemporal distribution and scales of mass wasting events, we analysed multiple images from 1969 to present (including optical images and synthetic aperture radar (SAR) images) and topography data from 2013 to present. Since 1969, there have been at least 19 obvious mass wasting events that can be divided into 3 subpatterns: ice‒rock avalanches (IRAs, 8 events), ice‒moraine avalanches (IMAs, 2 events), and glacier debris flows (GDFs, 9 events). Since 2017, the Sedongpu gully has entered the most active period, i.e. more than 68% of events occurred after 2017, and approximately 530 Mm3 and 185 Mm3 of materials were removed from mixtures of glacial and moraine (MGM) and glacial source areas (GSAs). Recent continuous warning states that the temperature of the Sedongpu gully area exceeded 0 °C from April to July 2012, and the 2017 Mw 6.4 Nyingchi earthquake was critical in the current intense erosion state.

Slope failure remediation using constrained horizontal‐to‐vertical spectral ratio inversion techniques

AbstractSlope failure rates may be exacerbated by increased precipitation patterns associated with climate change. Such events are extremely disruptive for local communities affected. Rapid engineering remediation solutions generally require immediate site characterization, including information on depth to intact bedrock and groundwater conditions – often on dangerous or still‐failing slopes. Horizontal‐to‐vertical spectral ratio is a low‐impact technique capable of rapidly providing key information on the subsurface. Here we develop a robust workflow for constrained minimization of horizontal‐to‐vertical spectral ratio data and develop constrained horizontal‐to‐vertical spectral ratio profiling methodologies. We present results from a number of landslide sites in eastern Australia and demonstrate the utility of horizontal‐to‐vertical spectral ratio in delineating both fractured‐rock aquifers at high‐risk sites and colluvium–bedrock contact on active landslide sites, where traditional seismic methods were not practical.