Slope Inclination Research Articles

Parametric Study of Rainfall-Induced Instability in Fine-Grained Sandy Soil

This study investigates the stability of fine-grained sandy soil slopes under varying rainfall intensities, durations, and geotechnical properties using a parametric analysis within GeoStudio. A total of 4416 unique parameter combinations were analyzed, incorporating variations in unit weight, cohesion, friction angle, slope inclination, slope height, rainfall intensity, and duration. Results reveal that rainfall intensity is the most influential variable on the factor of safety (FS), with higher intensities (e.g., 360 mm/h) on steeper slopes (e.g., 45°) leading to critical FS values below 1, indicating an imminent risk of failure. Under moderate conditions (e.g., 9 mm/h rainfall on slopes of 26.6°), the FS remains above 2. This dataset provides a valuable foundation for training machine learning models to predict slope stability under diverse environmental conditions, contributing to the development of early warning systems for rainfall-induced landslides.

A Multicriteria Approach for Landslide Hazard Zonation in the Lesser Kumaun Himalaya

ABSTRACTThe socioeconomic prosperity of a region is intricately tied to its infrastructure development, particularly the connectivity provided by highways. Preserving the economic well‐being of an area demands meticulous planning and the execution of construction projects with minimal risk. Landslide hazard zonation (LHZ) is a crucial tool for assessing the likelihood of landslide occurrences in specific regions. This study delves into the LHZ of a 171.2 km2 area, focusing on critical causative factors such as slope inclination and aspect, slope mass material, Land Use/Land Cover (LULC), distance from fault lines, roads, and drainage systems. The classification resulted in four distinct zones along the National Highway (NH‐109) stretch from Bhowali to Almora. Notably, the moderate‐hazard zone encompasses 60.4% of the area, followed by the high‐hazard zone at 24.4%, the low‐hazard zone at 11.9%, and the very high‐hazard zone at 3.3%. To enhance the reliability of the study, 63 previously identified landslide locations were marked based on diverse sources, including field studies and landslide inventory data from the Geological Survey of India (GSI). In the validation process, 12 past landslide occurrences were situated within the very high‐hazard zone, 32 in the high‐hazard zone, 18 in the moderate‐hazard zone, and only one in the low‐hazard zone. The receiver operating characteristic (ROC) curve yielded a commendable quality with a % area under the curve (AUC) of 71.2%. In summary, this research underscores the importance of LHZ in assessing and mitigating landslide risks along a stretch of the NH‐109 corridor. The findings provide valuable insights for informed decision‐making in infrastructure development and risk management, contributing to the sustainable growth and protection of the region's livelihood.

Experimental study of flame morphology in slope buildings under the influence of aspect ratio and ambient wind

Slope structures are commonly used in buildings, but such slope structures can exacerbate the rate of fire spread, complicate building fire safety and suppression, and lead to injuries, deaths, and property damage. Particularly, the thermal hazards posed by ambient wind on sloped fires remain unquantified. In this study, a propane burner was used to simulate the flame morphology behavior of a sloped building fire. 480 tests were conducted with varying aspect ratios (1∼8) of the fire source, different ambient winds (0 m/s∼3.5 m/s), and slope inclination angles (0°∼40°). Results demonstrate that the flame length initially increases and then decreases with an increment in ambient wind velocity. Moreover, with an increased aspect ratio of the fire source (length-to-width ratio), the turning point at which the flame length peaks shift to occur at a lower wind velocity threshold. The tilt angle and height of the flame change (respectively increases and decreases) significantly at lower ambient wind speeds and they tend to asymptotically approach respective constant values. As the ambient wind is further promoted. Existing physical models of flame morphology do not consider the combined effects of fire source aspect ratio, slope inclination angle, and ambient wind. A new slope entrainment restriction factor (EF) was proposed based on an analysis of the upward and leeward entrainment volumes. Using this factor, new models for flame morphology (including flame length, flame tilt angle, and flame height) were established. The accuracy and generalizability of the new flame models have been validated using reference data.

A new combined finite-discrete element method for stability analysis of soil-rock mixture slopes

PurposeThe purpose of this paper is to propose a new combined finite-discrete element method (FDEM) to analyze the mechanical properties, failure behavior and slope stability of soil rock mixtures (SRM), in which the rocks within the SRM model have shape randomness, size randomness and spatial distribution randomness.Design/methodology/approachBased on the modeling method of heterogeneous rocks, the SRM numerical model can be built and by adjusting the boundary between soil and rock, an SRM numerical model with any rock content can be obtained. The reliability and robustness of the new modeling method can be verified by uniaxial compression simulation. In addition, this paper investigates the effects of rock topology, rock content, slope height and slope inclination on the stability of SRM slopes.FindingsInvestigations of the influences of rock content, slope height and slope inclination of SRM slopes showed that the slope height had little effect on the failure mode. The influences of rock content and slope inclination on the slope failure mode were significant. With increasing rock content and slope dip angle, SRM slopes gradually transitioned from a single shear failure mode to a multi-shear fracture failure mode, and shear fractures showed irregular and bifurcated characteristics in which the cut-off values of rock content and slope inclination were 20% and 80°, respectively.Originality/valueThis paper proposed a new modeling method for SRMs based on FDEM, with rocks having random shapes, sizes and spatial distributions.

Possible effects of lumbar stabilization surgery on sagittal alignment, disability and quality of life

BackgroundIn order to restore the individual's health in lumbar stabilization surgeries, it is aimed to bring the sagittal alignment closer to normal values, to eliminate the findings, and thus to increase the quality of life of the individual by reducing the disability level. The aim of this study is to measure the effects of lumbar region stabilization surgeries performed in our clinic on some angular values in the spine, disability and quality of life. Preoperative (preop) and postoperative (postop) radiographs of 30 individuals over the age of 40 who applied to our clinic with various lumbar region complaints and underwent lumbar stabilization surgery between the years 2020–2022 were taken. Lumbar lordosis, pelvic tilt, sacral slope and pelvic inclination angles were measured from the images obtained. The Visual Analog Scale was used to measure the pain of individuals, the Oswestry Disability Index to measure the disability level, and the Nottingham Health Profile questionnaire to measure the quality of life. Preop and postop data were analyzed with the SPSS 23.0 program and p < 0.05 was considered significant.ResultsThe lumbar lordosis angles of individuals who underwent lumbar stabilization surgery approached normal values and the difference between preop–postop lumbar lordosis angle averages was significant (p < 0.05); It was observed that the harmony between the lumbar lordosis and pelvic inclination angles increased, the pain decreased and the difference between preop–postop pain values was significant (p < 0.05), disability levels decreased and quality of life increased.ConclusionsThe decrease in the level of disability and the increase in the quality of life seen in individuals who underwent lumbar stabilization surgery were associated with the decrease in pain; The changes in angular values are considered to be clinically significant.

Landslide susceptibility analysis and hazard zonation of Koh-e-Suleman range using weighted overlay technique

A healthy environment improves the quality of life on Earth, while natural disasters affect the quality of the environment. An area’s Landslide Hazard Zonation (LHZ) provides key information about the susceptibility to natural or manmade disasters. Using the Weighted Overlay Technique, this research aims to develop the landslide susceptibility and zonation mapping of Koh-e-Suleman Range (a hill station around the heritage site). Six causative factors are evaluated: geology, elevation, slope inclination, distance from streams, type of soil, and annual rainfall intensity, considering equal risk influence for all the factors. All causative factor maps were generated to yield equal classes and provide uniformity to the results except for soil types found in the study area. The findings indicate that the study area may comprise four landslide hazard zones with high, medium, low, and very low-intensity susceptibility of landslides. The accuracy of the final LHZ map is verified by comparing the hazard zonation area percentages with the global landslide inventory map from a macro-study of NASA. It was found that the study areas largely fall within low- and very low-hazard zones.

Numerical Modeling of Hydrological Mechanisms and Instability for Multi-Layered Slopes

The process of rainwater infiltration into unsaturated multi-layered slopes is complex, making it extremely difficult to accurately predict slope behaviors. The hydrological mechanisms in multi-layered slopes could be significantly influenced by the varying hydraulic characteristics of different soils, thus influencing slope stability. A numerical model based on Hydrus 2D was constructed to investigate the hydrological mechanisms of multi-layered slopes under different slope inclinations and rainfall intensities. The results revealed hydraulic processes in response to rainfall in unsaturated multi-layered slopes, in which layered soils retard the advance of wetting fronts and affect seepage paths in the slope. The results also showed the characteristics of hydraulic parameters, including pore water pressure and moisture content, under different conditions, and explained the crucial factors at play in maintaining slope stability.

Impact of Rear Slope Variation on Rubble Mound Breakwater Stability Under Seismic Loading

This study aims to enhance the seismic stability of rubble mound breakwaters, crucial maritime structures, by examining how variations in the rear slope angle affect their response to seismic loads. Utilizing the Plaxis 2D software, a finite element method was employed to simulate the behavior of a conventional rubble mound breakwater under different seismic conditions. The analysis considered three different rear slope angles and subjected each to various seismic loads characterized by differing amplitudes and frequencies. Our findings indicate that the rear slope inclination significantly influences the seismic response of the breakwaters, notably affecting the displacements and deformations within the structure. The most optimal angle of inclination was identified, which minimized the seismic-induced deformations, thereby potentially improving the structural integrity and longevity of these maritime defenses. This investigation not only provides valuable insights into the design of more resilient maritime structures but also introduces an approach to optimize breakwater design for better performance under seismic conditions, marking a notable improvement in the field of maritime engineering. Doi: 10.28991/CEJ-SP2024-010-08 Full Text: PDF

Soil resilience assessment using soil profile descriptions and Analytic Hierarchy Process in Mediterranean mountains considering diverse fire occurrences

Wildfires are complex natural phenomena that exert significant impacts on landscapes, societies, and economies. Understanding the concept of resilience is crucial in mitigating its possible negative impacts, as it involves preparing for, responding to, and recovering from wildfires. This research aims to demonstrate the utility of in situ soil profile description in assessing land use resilience using an Analytic Hierarchy Process (AHP) through an expert panel survey. The study examines a catchment located in the Balearic Islands, considering two fire occurrences (once and twice), comparing abandoned agricultural terraces and natural hillslopes. The results demonstrated that the priority ranking of variables to assess soil profile resilience against wildfires, determined by a panel of 10 experts, identified horizon depth (25.1%), slope inclination (21.5%), and hydrological connectivity (16.6%) as the most crucial factors. Other variables, such as number and size of roots, structure of pedal soil material, size class structure, and rock fragments, also contributed to resilience but to a lesser extent, with scores ranging from 5.7% to 9.6%. Analyzing the priorities established by the experts using AHP, the results showed that the least resilient soil horizon was H1 of the control hillslope, especially under high and low connectivity processes, which aligned with the loss of superficial soil horizons after one and two wildfires. Hillslopes showed greater changes in resilience after occurring wildfires compared to terraces, with the most significant alterations occurring after the second wildfire event. This study addresses a significant knowledge gap in the field by highlighting the interconnectedness of wildfires, resilience, and land use, providing insights into land management strategies for wildfire-prone regions.

Seismic stability and failure mechanisms of gentle and steep slopes considering soil rotated anisotropy and spatial variability

The present study focuses on investigating the effects of soil rotated anisotropy and spatial variability on slope failure in seismic conditions. The random finite element method aided by subset simulation is implemented, which ensures an efficient quantification of both the probability of failure and its associated consequence of failure. Several slope angles of gentle and steep slopes and soil properties that lead to a low probability of failure were selected for parametric studies. The comprehensive parametric studies of seismic slope stability analysis consider various factors such as slope inclinations, seismic coefficients, scales of fluctuation, and orientations of the major principal scale of fluctuation (i.e., the rotation angle of random field). The results underscore the importance of considering the combined effects of soil anisotropy and the orientation of the major principal scale of fluctuation for designing both gentle and steep slopes under seismic conditions and emphasize that care must be given to ensure the worst-case scenario is considered. Visual observations of failure mechanisms of gentle and steep slopes under seismic conditions were also shown to be very helpful in interpreting the variation of probability of failure due to soil spatial variation.

Rock Mass Characterization and Slope Stability Analysis Inlet Portal of Jragung Dam Diversion Tunnel, Indonesia

Abstract Slope stability is a serious problem that academics are still looking into in terms of human safety, equipment, and structures along the slope. Failure on slopes happens for a variety of reasons, including rock physical and mechanical properties, discontinuity factors, slope geometry, and external variables like as rainfall and seismic activity. The research location was conducted on the Jragung dam diversion tunnel, administratively located in Candirejo village, Pringapus sub-district, Semarang, Central Java Province. The purpose of this study was to use an empirical and numerical method to investigate the impact of rock mass categorisation on slope stability. The RMR (Rock mass rating) method is used to characterize rock mass, and the SMR (Slope mass rating) method is used to measure slope stability. The numerical slope stability analyses were carried out with the help of Phase2 (Rocscience, Inc.). The results showed that the slope at the intake portal was class IV (poor), and that it was unstable utilizing the SMR technique. According to numerical research, the basic design cut slopes with a 51° inclination were found to be unstable even after strengthening. It was suggested that the slope geometry and support measures be adjusted even more. Modified cut slopes were found to be stable after the slope inclinations were changed from 51° to 27° and shotcrete and rock bolt reinforcement were added.

Effects of different slopes on hip and ankle biomechanics of replaced and non-replaced limbs of patients with total knee arthroplasty during incline ramp walking

Although knee biomechanics has been examined, hip and ankle biomechanics in incline ramp walking has not been explored for patients with total knee arthroplasty (TKA). The purpose of this study was to investigate the hip and ankle joint kinematic and kinetic biomechanics of different incline slopes for replaced limbs and non-replaced limbs in individuals with TKA compared to healthy controls. Twenty-five patients with TKR and ten healthy controls performed walking trials on four slope conditions of level (0°), 5°, 10° and 15° on a customized instrumented ramp system. A 3x4 (limb x slope) repeated analysis of variance was used to evaluate selected variables. The results showed a greater peak ankle dorsiflexion angle in the replaced limbs compared to healthy limbs. No significant interactions or limb main effect for other ankle and hip variables. The peak dorsiflexion angle, eversion angle and dorsiflexion moment were progressively higher in each comparison from level to 15°. The peak plantarflexion moment was also increased with each increase of slopes. Both the replaced and non-replaced limbs of patients with TKA had lower hip flexion moments than the healthy control limbs. Hip angle at contact and hip extension range of motion increased with each increase of slopes. Peak hip loading-response internal extension moment increased with each increase in slope and peak hip push-off internal flexion moment decreased with each increase of slope. Our results showed increased dorsiflexion in replaced limbs but no other compensations of hip and ankle joints of replaced limbs compared to non-replaced limbs and their healthy controls during incline walking, providing further support of using incline walking in rehabilitation for patients with TKA.

Effects of jet grouting on adjacent ground through numerical modelling

When using jet grouting for soil stabilisation, effects of the installation process need to be evaluated. This could be particularly important for applications in challenging ground conditions and low initial ground stability. This study investigates such effects in soft marine clays using numerical finite-element (FE) simulations for both flat and sloping terrains. Additionally, an analytical solution using the modified Hagen–Poiseuille equation was developed to (a) assess the pressure induced by the grout at any installed depth and (b) illustrate the importance of maintaining a proper amount of return flow to avoid build-up of excessive pressures in the ground during the jet-grouting process. Combining the analytical and the FE simulations, jet-grouting induced soil displacements, were determined. For flat terrain, the area affected by jet grouting was approximately three to four times the column radius. By contrast, for the studied slope (inclination of 1 : 3), the influenced area increased to about ten times the column radius. The obtained displacement magnitude was also considerably larger for sloping terrain than for flat terrain. The reported findings relate to jet grouting in marine clays (which is not the normal application of this technology) and cannot be extrapolated to other soils.

Injury Risk Predictions in Lunar Terrain Vehicle (LTV) Extravehicular Activities (EVAs): A Pilot Study

Extravehicular activities will play a crucial role in lunar exploration on upcoming Artemis missions and may involve astronauts operating a lunar terrain vehicle (LTV) in a standing posture. This study assessed kinematic response and injury risks using an active muscle human body model (HBM) restrained in an upright posture on the LTV by simulating dynamic acceleration pulses related to lunar surface irregularities. Linear accelerations and rotational displacements of 5 lunar obstacles (3 craters; 2 rocks) over 5 slope inclinations were applied across 25 simulations. All body injury metrics were below NASA’s injury tolerance limits, but compressive forces were highest in the lumbar (250–550N lumbar, tolerance: 5300N) and lower extremity (190–700N tibia, tolerance: 1350N) regions. There was a strong association between the magnitudes of body injury metrics and LTV resultant linear acceleration (ρ = 0.70–0.81). There was substantial upper body motion, with maximum forward excursion reaching 375 mm for the head and 260 mm for the chest. Our findings suggest driving a lunar rover in an upright posture for these scenarios is a low severity impact presenting low body injury risks. Injury metrics increased along the load path, from the lower body (highest metrics) to the upper body (lowest metrics). While upper body injury metrics were low, increased body motion could potentially pose a risk of injury from flail and occupant interaction with the surrounding vehicle, suit, and restraint hardware.

Interaction between two large particles in a dry granular shear flow.

The interaction between two large spherical particles, called intruders, in a dry granular flow down an incline is brought to light and studied experimentally and numerically. Several parameters are varied, namely, the size ratio between the intruders and the small flowing particles, the thickness of the granular flow, the incline slope and roughness, and the densities of the intruders with respect to the small-particle density. In all cases, intruders get aligned with the flow. A thorough parametric study shows that a transition occurs between attractive and repulsive regimes of interaction: at steady state, intruders either flow at a defined longitudinal distance, which may be zero with intruders in contact, or stand as far apart as possible. The mean longitudinal and vertical distances between the intruders are found to be tightly linked, with all points plotting the pairs on a single, master curve. The wake and shear effects are shown to control the relative position of the intruders. They may be modulated due to the weight and buoyancy of the intruders, and to local modifications of the collisions between intruders and small flowing particles because of the proximity of the incline bottom or the flow surface.

IMPLEMENTATION OF MAPPING-BASED MACHINE LEARNING ALGORITHM AS NON-STRUCTURAL DISASTER MITIGATION TO DETECT LANDSLIDE SUSCEPTIBILITY IN TAKARI DISTRICT

This research is primarily dedicated to providing a comprehensive exposition of the methodology applied in the deployment of a cartographic-based machine learning algorithm designed for the precise identification of areas susceptible to landslides within the geographical confines of the Takari District.This research delves into the application of mapping-based machine learning algorithms in the domain of non-structural disaster mitigation, with a specific emphasis on the detection of landslide susceptibility within the Takari District. A range of machine learning algorithms, including Support Vector Machine, Naive Bayes Classifier, Ordinal Logistic Regression, Random Forest, and Decision Tree, were harnessed to evaluate rainfall data within the context of landslide susceptibility. An evaluation of model performance, anchored in accuracy and Kappa metrics, unveiled that both the Ordinal Logistic Regression and Random Forest models exhibited noteworthy precision, reaching a commendable 74.36%. Nevertheless, a meticulous examination of Kappa values disclosed the ascendancy of the Random Forest model, which achieved a superior Kappa value of 0.5397. As portrayed in the visual representation provided, it becomes manifest that the Random Forest algorithm's prognostications yield 66 instances of cloudy atmospheric conditions, 48 occurrences of light precipitation, and 3 episodes of moderate rainfall. These predictions are influenced by several factors, including average temperature, humidity levels, wind speed, duration of sunlight, and wind direction at maximum speed. Consequently, this comprehensive analysis underscores the Random Forest algorithm as the most efficacious model for landslide susceptibility prediction. Furthermore, the study seamlessly integrated overlay maps, encompassing the Slope Inclination Map of the Takari District, Geological Map of the Takari District, and Soil Type Map of the Takari District, to contribute to the formulation of a definitive map delineating the susceptibility to landslides in the Takari District. Furthermore, further research could conduct spatial validation of the model predictions using additional datasets or remote sensing data to validate the accuracy of the landslide susceptibility map and ensure its applicability across different geographical regions.

An EPR model for predicting the bearing capacity of single and double-strip foundations near earth slope crests.

It is imperative to understand how foundations behave on earthen slopes to accurately predict their allowable carrying capacity in geotechnical engineering. A comprehensive finite element (FE) simulation with PLAXIS 2D was conducted to assess the effects of various parameters on the bearing capacity (BC) of single- and double-strip foundations placed near the earth's slope crest. The specified parameters include foundation width (B) and depth (Df/B); setback distance between the slope edge and foundation (b/B); soil internal friction (ϕ) and cohesion (c); slope inclination (β); and spacing between foundations (S/B). In addition, the numerically simulated database was used to develop simple mathematical expressions for predicting the capacities in both cases using evolutionary polynomial regression (EPR). The results revealed that the bearing capacity of single- and double-strip foundations increased with an increase in all studied parameters except slope inclination. For single-strip foundations, the outcomes demonstrated that slope inclination has no impact on BC when it is located 6B from the slope edge. However, under interference conditions, the critical center-to-center spacing between foundations is 3-4B, beyond which they behave as individual foundations. Additionally, EPR provides a robust method of predicting the BC of single- and double-strip foundations within slope crests based on the strong correlation of various statistical criteria between simulated and predicted results from training, validation, and testing. Finally, according to sensitivity analysis, in both single and double-strip foundations resting on an earthen slope crest, b/B, B, and ϕ are the most important input parameters that impact the output results.

Methodology for determining the scope of reclamation works when forming recreational zone in the quarry residual space

The article is devoted to the development of methodological recommendations aimed at increasing the recreation territory during reclamation, taking into account the flooding of the quarry residual space. Calculations of the reclamation works volume during the forming of a recreation area on the quarry slope were made. The influence of the embankment section width of the soil in the flooded quarry space on the embankment geometric shape was established. Calculating method of the reclamation works volumes are proposed, taking into account the indicators of the slope inclination angle and the height of the embankment being formed. A scheme for the safe recreation area location within the quarry residual space has been developed, which allows determining the necessary parameters of the mining elements that affect on the volume of embankments construction. A method of determining the volume of works for the formation of a recreation area in the quarry is proposed, taking into account the embankment width and height, the resulting slope angle, the safe angle of mining rocks inclination at the dumping into flooded quarry. It has been established that the volume of reclamation depends on the embankment parameters when the quarry watered area is changed.

GEOMONITORING OF THE OPEN-PIT MINE SLOPES DURING SUBSOIL DEVELOPMENT

The concept of geomonitoring and its role in developing the mining industry as a case study of the development of copper and zinc deposits in central Kazakhstan ("East Saryoba" mine) has been considered. As a crucial element of the geomonitoring concept, the control of the open-pit mine's slope stability has been examined. Geomonitoring is being treated as a combination of geodetic monitoring data and geomechanical properties of the surrounding rocks to analyze the possible slopes' collapses. The refined approach of geomonitoring has been developed to provide appropriate reliability and accuracy. The technology is based on complex knowledge about the geological structure of the object of monitoring and applying state-of-the-art geodetic methods. Research on the geomechanical properties of the open-pit mine has been carried out. The results of these studies have been used to determine the collapse zones of the slopes of the open-pit mine. The limit values for the slopes' collapse zone and inclination angle for the prospective excavation regions in the open-pit mine have been calculated using the equilibrium state equation. Those values, namely, the size of the collapse zone and the slope's inclination angle, were used for the geodetic target setup. As a case study, the displacements of these targets were measured using robotic total stations placed on the control points over the geodetic network. For the installation of both geodetic equipment during the geomonitoring design and accomplishment, the authors developed the permanent measuring station construction, which provides fast and accurate centering. The first results showed that the problem of the geomonitoring design could be solved based on geomechanical rock properties accounting and their combination with the results of geodetic measurements.

Numerical study on modeling the soil footpad interaction of lunar soft landers at touchdown

Soft landers are a common systems for planetary exploration and have been successfully landed on Moon, Mars and the comet Churyumov–Gerasimenko. In this study numerical simulations of the touchdown process of soft landers on the moon surface are presented. The focus is on the soil footpad interaction and the resulting loading on the primary strut of the landing gear. Main influence parameters like slope inclination, touchdown velocities and soil properties are varied to show each individual influence on the structural loading of the landing gear. The numerical simulations are done using the CEL-Method allowing for significant soil deformation at touchdown.