Characteristics Of Slope Failures Research Articles

Characteristics of Slope Failures Seen outside the Designated Landslide-prone Areas

Characteristics of Slope Failures Seen outside the Designated Landslide-prone Areas

Numerical investigation of the failure mechanisms of soil–rock mixture slopes by material point method

A new technique for establishing material point method (MPM) models of soil–rock mixture slopes was proposed to accurately analyze the large-deformation failure mechanisms of soil–rock mixture slopes. First, natural rock block contours were obtained through a digital image processing technique, followed by analyzing and reconstructing the rock block contours with the help of the discrete Fourier transform theory. Next, The discrete models of soil–rock mixture slopes for MPM were constructed by combining the stochastic placement algorithm with the digital image processing technique. Moreover, using the MPM, the influences of the content, the size, and morphology of rock blocks on the failure mechanisms of the slopes were investigated in detail. The results reveal that the content, features, and spatial distribution of rock blocks significantly influence the slope failure characteristics. Owing to the existence of rock blocks, the plastic zone of a slope at failure becomes heterogeneous and complex, showing multiple sliding regions and failure modes.

STRUCTURAL GEOLOGY FAULT EFFECT ON HIGHWALL COAL MINING AND FAILURE EVALUATION BASED ON VELOCITY DATA AT BENGALON, EAST-KUTAI DISTRIC, EAST KALIMANTAN PROVINCE.

The geological structure especially folds and faults will reduce slope stability at slope mining where many events are the main factors that trigger slope failure. The geological structure "unknown" is defined as a minor geological structure that was not defined in the initial geological modeling. This uncertainty geological structure is critical issue during the mining process in coal mining. Slope stability Radar is a monitoring instrument that has been used in this research. In SSR data analysis, graphical behavior from velocity data is for monitoring program. The analysis in this research consisted of measuring the geological structure in the area where slope failure occurred and reading the velocity acceleration data from SSR instrument.Slope failure in this research study conduct on the high-wall coal mining which is in line with the geological structure plane with direction N 2460 E and dip 480, along + 150 m and at elevations RL +30 to RL -10. Velocity value at the time of slope failure was 13,568 mm/hour. This value can then be used as a reference as the “Progressive Velocity” value before the slope failure occurs at certain slope wall conditions.The content case study is expected to help engineers in increasing confidence in determining the characteristics of slope failure based on Velocity data in areas that have a geological structure, however, this study research aims to determine basic behavior in the SSR monitoring program and serve as a reference in the risk management program in the coal Mining industry.

Assessing the Generalization of Machine Learning-Based Slope Failure Prediction to New Geographic Extents

Slope failure probabilistic models generated using random forest (RF) machine learning (ML), manually interpreted incident points, and light detection and ranging (LiDAR) digital terrain variables are assessed for predicting and generalizing to new geographic extents. Specifically, models for four Major Land Resource Areas (MLRAs) in the state of West Virginia in the United States (US) were created. All region-specific models were then used to predict withheld validation data within all four MLRAs. For all validation datasets, the model trained using data from the same MLRA provided the highest reported overall accuracy (OA), Kappa statistic, F1 Score, area under the receiver operating characteristic curve (AUC ROC), and area under the precision-recall curve (AUC PR). However, the model from the same MLRA as the validation dataset did not always provide the highest precision, recall, and/or specificity, suggesting that models extrapolated to new geographic extents tend to either overpredict or underpredict the land area of slope failure occurrence whereas they offer a better balance between omission and commission error within the region in which they were trained. This study highlights the value of developing region-specific inventories, models, and high resolution and detailed digital elevation data, since models may not generalize well to new geographic extents, potentially resulting from spatial heterogeneity in landscape and/or slope failure characteristics.

Overview of Stability and Failure Characteristics of Expansive Soil Bank Slope

Expansive soil is a type of special clay that expands and softens after water absorption and shrinks and cracks after water loss. It tends to cause engineering accidents such as slope deformation and landslide damage. This paper summarizes the interaction between three engineering properties of expansive soil as well as the slope failure characteristics based on case analysis. In this way, this paper can contribute its share to the design, construction and operation management of the expansive soil bank slope.

Characteristics of Slope Failure in Yamaguchi Prefecture Triggered by the Heavy Rain Event of July 2018

Characteristics of Slope Failure in Yamaguchi Prefecture Triggered by the Heavy Rain Event of July 2018

Experimental and numerical investigations of the seismic response of a rock–soil mixture deposit slope

Inertial instability-induced slope failure is one of the most destructive seismic hazards encountered in China. Depositional slopes are widely distributed across the south-western part of China. To study the seismic performance of rock–soil mixture deposit (RSMD) slopes in detail, physical and mechanical tests of air-dried RSMD, and a 1:50 geometric scale, generalised RSMD slope centrifugal shaking table modelling tests were conducted. The acceleration response, slope deformation, and instability mode of the air-dried RSMD slope under the continuous action of four earthquakes with different intensities are analysed. Besides, the dynamic finite-difference numerical simulations were performed with FLAC to simulate the centrifuge model test. The numerical simulation results were compared with the test results in terms of the horizontal acceleration response, time history of crest settlements, and the slope failure characteristics. The results show that the horizontal peak ground acceleration (PGA) amplification factors of the RSMD slope reflect typical elevation, and surface, amplification effects. In addition, the spectral distribution of the seismic wave has changed significantly with propagation along the slope elevation. The energy of input seismic wave in a frequency range close to the natural frequency of an RSMD slope is significantly amplified. During the test, it was observed that the failure of an air-dried RSMD slope occurred when the PGA reached 0.216 g, and the settlement at the crest of the slope was obvious. The failure mode was dominated by shallow collapse.

Case study of slope deterioration characteristics: Simbal Landslide, Salt Range, Pakistan

For a slope structure, various deterioration phenomena progress in the slope over time, and failure may occur, which decreases the durability life and service life. The approach to slope stability due to deterioration is a different concept from the existing limit equilibrium analysis, which is limited to the physical characteristics and geometrical structure of the ground and groundwater. In this study, with a comparative review of various literatures related to the slope failure characteristics due to deterioration, the optimal formulas for shear strength reduction such as the exponential function, logarithmic function, and inverse hyperbolic function are found to be the best fits for the variations in strength reduction. In addition, a case study was performed for the Simbal Landslide, Salt Range, Pakistan, where the slope failure of some carbonate rock formations vulnerable to deterioration occurred. As a result, it was confirmed that landslide occurred because of the reduction in shear strength by deterioration, since the safety factor was approx. 1.0 when the slope failure occurred. Finally, as a quantitative approach to evaluate the slope stability due to deterioration, a methodology to evaluate the slope stability using the limit equilibrium analysis of the slope with optimal strength reduction curves was proposed.

Geomorphological characteristics of slope failures in northeast Viti Levu island, Fiji, triggered by Tropical Cyclone Winston in February 2016

The highways circumnavigating Viti Levu play a pivotal role in Fiji's socioeconomic development, and are a crucial link to transport aid during disasters. Slope failures triggered by heavy rainfall and tropical cyclones have led to considerable damage and fatalities along Viti Levu's main roads in the past. Knowledge of slope instability mechanisms is key for the successful identification and management of slope failure hazards, however, there is a paucity of such information for Fiji's main roads. Severe Tropical Cyclone (STC) Winston was the strongest cyclone on record to make landfall in Fiji and affected the Fiji Islands from the early hours of 20 February until 3 am, 21 February, 2016. We present a field reconnaissance examining the characteristics and mechanisms of slope failures induced by STC Winston along a 35 km stretch of the northern part of the Viti Levu's ring road, “Kings Road”. Approximately 61 distinct shallow, small‐scale slope failures were identified most of which were of a complex type and included earth and debris slides (planar and rotational) with a minor flow component. The trigger for the slope failures was the ~258 mm of rainfall in 24 hours after 30‐days of antecedent rainfall totalling 482 mm. This caused rapid increases in porewater pressures, especially at the contact of residual soils and the underlying weathered basement rock. Evidence of recurring slips along Kings Road indicates that contemporary slope instability is likely caused by elevated porewater pressure during high intensity rainfall events in clay‐dominated soils.

An experimental investigation on slope stability under drawdown conditions using transparent soils

This paper presents an experimental investigation into slope failure during water-level drawdown using transparent soil. The internal characteristics of slope failure are not well-known due to the limitations of the techniques used in the experiments conducted to date. In this study, transparent soil is used to visualize the process of slope failure. We developed a water-level control system to implement simulation of the drawdown of the water level at various speeds and used a charge-coupled device camera to capture images during the entire slope failure process. Particle image velocimetry was used to measure the displacement of the sand particles and identify the sliding zones. The flow paths of the fluid inside the slope were illuminated using an organic dye. The results show that the slope failure process can be divided into two stages: surface and overall sliding. The overall sliding of the slope is caused by the gradual development of partial instability, and the failure mode is a cyclic failure. The slope angle is different above and below the water level during the process of sliding. In our experiments, the slope angle is about 20° above the water level, which is the same as the final stable slope angle, and about 35° below the water level, which is the same as the initial slope angle. This means that the drawdown influences the angle above the water level but has little influence on the angle below the water level. The results of this paper provide a better understanding of the physical behavior and failure mode of soil slopes caused by drawdowns near the coast.

Hydrological responses and stability analysis of shallow slopes with cohesionless soil subjected to continuous rainfall

Understanding the hydrological and physical responses of shallow slopes subject to rainfall events is vital for the efficiency of a warning system setup. In this research, a series of experiments were undertaken to evaluate the hydrological responses of shallow slopes of varying steepness and when subjected to varying intensities, periods, and inter-storm periods of rainfall. An analysis of infinite slopes was also undertaken to develop a fundamental understanding of rainfall-induced shallow slope failure characteristics. The hydrological and physical responses were characterized in the infiltration and saturation phases. During the infiltration phase, the maximum magnitude of water content was found behind the wetting front, termed as the water content behind the wetting front (θwb). For a certain soil type, the magnitude of θwb was found to be dependent on the magnitude of rainfall intensity, regardless of the slope gradient and initial water content. Based on the relative depth of the failure plane, the failure can be categorized by three prime modes: (i) along the impervious layer mode, (ii) shallow depth mode, and (iii) transitional mode. These modes can be characterized by the magnitude of a stability index termed as [Formula: see text] ratio. An infiltration index, termed as i/ks ratio, was found to play a role in the depth of the failure plane only for the transitional mode.

Characteristics of Slope Failures in Tropical Hill Slopes of South West India

Characteristics of Slope Failures in Tropical Hill Slopes of South West India

Slope Failure Characteristics and Slope Movement Susceptibility Assessment Using GIS in a Medium Scale: A Case Study from Ouled Driss and Machroha Municipalities, Northeast Algeria

GIS-based slope movement susceptibility (SMS) map is developed for both the Ouled Driss and Machroha districts of northeastern Algeria, using the logistic regression technique. Slope movement (SM) locations were spotted using the data from various sources. An inventory map containing 489 events occurred between 1987 and 2013 was used to extract the dependent variable. SM-related factors such as slope gradient, slope aspect, topographical elevations, lithology, faulting, drainage system, road network, land use, precipitations, and seismic disturbances were considered as independent variables. The effect of each parameter on SM occurrence was deduced from the corresponding coefficient that appeared in the logistic regression function. The results of this study indicated that slope gradient, lithology, and precipitations were statistically significant in predicting slope instability. The susceptibility map produced in this paper classified the study area into five categories of SMS. The high and very high susceptibility zones made up 38% of the total extent of the two commons and involved mid-altitude slopes in their central, eastern, and southern parts. The quality of the SMS map was validated, and it can be used for planning protective and mitigation measures.

Discontinuous slope failures and pore-water pressure variation

Field experiments were conducted under artificial rainfalls to investigate the processes of soil failures on slope. It is found that the failures were temporally discontinuous and spatially discrete, with a wide range of magnitudes, accompanied by variations of soil moisture and pore-water pressure. Specifically, the experiments indicate that soil failures are more likely to occur on slope with high content of fine particles; the pore-pressure varies in response to soil failures in that the failures evidently affect the pore of the underlying soil. Migration of fine particles from upper to lower part of the slope also impacts the pore-water pressure variations in the slope profile. It is concluded that soil heterogeneity has a significant effect on variation in pore-water pressure, and fine particles transportation influences the building of pore-water pressure, as well as the mass depth, initial porosity, which is key to understanding the spatial characteristics of slope failures.

Analysis of slope failure characteristics in Uono River Watershed

Analysis of slope failure characteristics in Uono River Watershed

The mechanisms and geotechnical characteristics of slope failures at a mining district, southeast Nigeria

A procedure encompassing field, laboratory and numerical analyses was employed to re-analyze the mechanism of slope failures at a mining district in south eastern Nigeria. The slopes have been re-evaluated on the basis of new evidence. The study identified 43 landslide events which were mainly shallow, short run-out slides triggered during rainfall. The sand grains were analysed by scanning electron microscope for evidence of microstructures, surface texture and grain crushing. The analysis revealed that the soil particles associated with landslide are somewhat rounded, fairly sorted, and absence of any grain crushing. Shearing tests were carried out at various normal stress and relative density conditions. The specimens with relative density of about 32 % responded to shearing in a strain-softening pattern; and as normal stress and over-consolidation ratio increased, there was no transition from contractive to dilative behaviour. On the contrary, under a constant normal stress (196 kPa) and increasing relative density (from 45.9 % to 75.5 %), the soils exhibited dilative behaviours. It is shown that increase in relative density, normal stress or overconsolidation ratio did not affect the brittleness index significantly. A numerical method based on strength reduction technique simulated a landslide which structure, run-out distance and distribution area were consistent with field observations. It is deduced that the slopes are unstable under intense rainfall conditions due to the effects of soil characteristics, excess pore water generation and the alternating swelling and shrinkage of the claystone layers interbedded with the sand bodies.

平成21年7月に山口県防府市で発生した土砂災害における源頭部崩壊と土石流の状況とその地形的特徴

平成21年7月に山口県防府市で発生した土砂災害における源頭部崩壊と土石流の状況とその地形的特徴

Numerical Analysis of Characteristics of Moisture Migration in Soil Slope under Rainfall

Based on the characteristics of slope failure induced by rainfall, from the point of view of moisture migration and combining unsaturated soil mechanics, the characteristics of moisture migration in slope under different rainfall intensities were analyzed by finite element method. The results reveal that under rainfall, the pore water pressure in slope is in layered distribution, and at the bottom of slope, the pore water pressure is the highest, the top is lower and the middle is the lowest. The volumetric water content is in nonlinear distribution and the degree of nonlinear in unsaturated area is higher than that of the saturated area. The permeability coefficient of soil rises with the increase of rainfall intensity, and when the soil is saturated, its permeability coefficient is saturate permeability coefficient.

CHARACTERISTICS OF SLOPE FAILURES IN MAKINOHARA, JAPAN

Makinohara City, located in south-central Shizuoka Prefecture in Japan, is renowned for the production of high quality Japanese green tea. Approximately 25% of Makinohara City's land is used as tea plantation fields and annually 5,800 tonnes of tea is produced. However, slopes in this region are occasionally subject to failures following construction activities. In this light, this paper investigates characteristics of slope failures in Makinohara region. Based on the author's experience, a number of recommendations are also made for slope analysis and mitigation works.

Characteristics of slope failure by the local downpour on September 4, 2007 in Kotoura-town, Tottori prefecture

Characteristics of slope failure by the local downpour on September 4, 2007 in Kotoura-town, Tottori prefecture