Slope Stability Factor Research Articles

Stability assessment for hard anti-inclined bedded rock slopes using a limit equilibrium method

The failure mechanism of hard anti-inclined bedded rock slopes with the possibility of undergoing flexural toppling is very complex so that it is difficult to effectively perform their stability assessment. In this study, an attempt was made to accurately predict the stability factor and the failure surface of such slopes: establishing a new failure zone model and developing a limit equilibrium method based on this model. In this model, the failure zones of such a slope were divided strictly according to the failure mechanisms of the rock layers. In the presented method, the failure surface was considered to be a bilinear-type surface as observed in field investigations and laboratory tests, and the non-dimensional parameter indicating the position of application of the interlayer force was revised by deriving the distribution and the equivalent substitution of interlayer force. Then, a comparative study on Yangtai slope was performed to prove the presented method, and the effect of the non-dimensional parameter on the stability was also investigated. The results reveal that the presented method can accurately determine the failure surface and precisely evaluate the slope stability factor. In addition, the presented method has higher predictive accuracy compared with other analytical methods. With the decrease of the non-dimensional parameter, the stability of the slope is reinforced, but the larger landslide with more serious damage effect will occur if the slope undergoes the overall failure.

Study on Influencing Factors of Unsaturated Loess Slope Stability under Dry-Wet Cycle Conditions

In practical engineering, slopes are in rainfall-evaporation environments over long periods. Considering the dry-wet cycles effect on unsaturated loess slope instability is of great significance. In this paper, a soil–water characteristic curve test of unsaturated loess is carried out. Combined with the prediction model, the curve between the volumetric water content and unsaturated permeability coefficient is obtained, and the obtained curve is used as the material assignment condition for slope stability analysis. The results show that dry-wet cycles affect slope stability by changing the volumetric water content and unsaturated loess permeability coefficient of unsaturated loess. The more dry-wet cycles there are, the larger the unsaturated permeability coefficient. With increasing volumetric water content, the slope stability decreases. Under the same dry-wet cycle conditions, the greater the rainfall intensity and the longer the rainfall duration, the easier the slope is to be unstable. The influence of the dry-wet cycle effect on the slope stability is weakened with an increasing number of cycles. When more than 5 dry-wet cycles are carried out, the slope safety factor tends to be stable.

SEEPAGE MODELING IN EMBANKMENT DAMS WITH VARIOUS SUB SOIL CHARACTERISTICS

The embankment dam has the advantage that it can be built in all sub-base conditions although poor topography, but the weakness is seepage, so research on seepage is needed. This study uses numerical modelling with the GeoStudio program: SEEP/W and SLOPE/W. The data used is data from the Tugu Dam, Trenggalek, while the subbase data used five soil types, namely clay, silty clay, silt, silty sand, and sand. This research simulation is divided into two; the first simulation is the condition of the soil characteristics remains with the water level increasing every 5 meters from the base elevation of the dam to below the floodwater level;. In contrast, the second simulation is the condition of the water level elevation remains constant, but the soil characteristics change. Each simulation will be checked for seepage discharge and soil stability. The first simulation results show that seepage discharge and water level elevation have a logarithmic correlation with R 2 > 0.75. The largest seepage discharge of 1,90 x 10 -3 m 3 /s is sand soil, while the smallest is clay soil of 1,47 x 10 -9 m 3 /s. The results of the second simulation show that the seepage discharge and saturated volumetric water content also have a logarithmic correlation, but some results cannot be used because they have an R 2 value < 0.75. From the two simulations, the seepage discharge that occurs is said to be safe because it is below the average annual runoff which is 1% of the 10-year re-flood discharge calculated using the Nakayasu Synthetic Unit Hydrograph (HSS) which is 5.99 m 3 /s, and the safety factor of slope stability is > 1.2 then the dam is considered stable.

Cut slope stability assessment along forest roads using the limit equilibrium approaches and Slide software

Calculating the factor of safety (FS) as slope stability factor is necessary to prevent environmental damage. Therefore, this paper aims to (i) calculate FS using the limit equilibrium approaches and Slide software and (ii) investigate the stability of slopes according to calculated FS (Janbu and Bishop methods) and status of different sites in the study area (Hyrcanian forest of Iran). Six landslides were selected along the forest road by a field survey. Landslide dimensions including length, width, and height were measured using meters. Slope gradients were measured using the Suunto clinometer. The Slide software was used to evaluate the stability analysis of slopes. According to laboratory tests on soil samples the average of the liquid limit was recorded as 58%. The results of the direct shear test showed that the rate of soil cohesion (c) and coefficient of friction angle (φ) decreased with an increase in moisture content. According to the results, the factors of safety for landslide sites (Sites 1–6) were calculated to be 1.3, 0.65, 0.76, 0.55, 1.19 and 1.51, respectively. These calculated FS can accurately determine the slope status in terms of slope stability. According to the software classification, the status of Site 1 is “susceptible to landside”. Sites 2, 3 and 4 are “very high risk”. Also, the status of Sites 5 and 6 are “high risk” and “stable”, respectively. The instability of the slopes in studied sites is related to the drainage system (lack of culverts or ditches) as well as marlstone as bedrock. According to the calculated FS in different sites and comparison of the obtained results with the real conditions of sites, it can be concluded that the slope stability analysis in the Slide software is very accurate and it can be used to determine the factor of safety under different conditions in terms of morphology, hydrology and soil mechanics.

Searching Method of Critical Slip Surface of Slope Based on Improved Wolf Swarm Algorithm

Determining the critical sliding surface and calculating the safety factor of slope stability are the key problems of slope stability analysis. Firstly, according to the characteristics of the existing wolf swarm algorithm, an improved wolf swarm algorithm is proposed, which abandons the assumption of a circular sliding surface. Then, a multipoint spline curve is introduced to describe the shape of a slope sliding surface. The optimization of the curve can determine the critical slip surface of slope and avoid falling into the local optimum. This method is programmed and implemented in Python, and then, accuracy and reliability are verified through typical slope cases and engineering examples, and the sensitivity analysis of factors that have great influence is carried out. The research results show that the slope sliding surface search method based on the improved wolf swarm algorithm can effectively and quickly determine the critical sliding surface of the slope. Compared with traditional methods, it has higher convergence accuracy and reliability. It provides an effective method for slope stability analysis.

The Impact of Climate Changes on Slope Stability and Landslide Conditioning Factors: An Example from Kravarsko, Croatia

The Gajevo landslide in the Kravarsko area (Vukomeričke Gorice hilly area, northern Croatia) was chosen for investigation due to the existing landslide risk for the households at the landslide crown. Available data are limited, but a new landslide map and cross-section was developed within the presented research, mostly based on detailed light detection and ranging (LiDAR) data and field mapping. By comparing available orthophotos of the landslide, resident testimonies, precipitation data, and media releases, it was concluded that the landslide was activated in February 2014. The landslide was primarily triggered by increased precipitation (its measured variations could be in direct connection with ongoing global climate changes), but natural terrain features and anthropogenic factors also affected slope stability. New findings have led to the conclusion that the existing landslide area is large and complex and the crown and head scarp area should be stabilized by urgent remediation measures.

Slope with Predetermined Shear Plane Stability Predictions under Cyclic Loading with Innovative Time Series Analysis by Mechanical Learning Approach.

We propose a mechanical learning method that can be used to predict stability coefficients for slopes where slopes with predetermined shear planes are subjected to cyclic seismic loads under undrained conditions. Firstly, shear tests with cyclic loading of different parameters were simulated on designated slip zone soil specimens, in which the strain softening process leading to landslide occurrence was closely observed. At the same time, based on the limit equilibrium analysis of the Sarma method, the variation of slope stability coefficients under different cyclic loads was investigated. Finally, a Box–Jenkins’ modeling approach is used to predict the data from the time series of slope stability coefficients using a mechanical learning approach. The simulation results show that (1) reduction in coordination number can be an accurate indicator of the level of strain softening and evolutionary processes; (2) the gradual reduction of shear stress facilitates the soil strain softening process, while different cyclic loading stress amplitudes will result in rapid penetration or non-penetration of the fracture zone by means of particulate flow. Although the confining pressure of the slip zone soil can inhibit the increase of fractures, it has a limited inhibitory effect on strain softening; (3) based on field observations of the slope stability factor and stress field, two possible landslide triggering mechanisms are described. (4) Mechanical learning of time series can accurately predict the changing pattern of stability coefficients of slopes without loading. This study establishes a potential bridge between the geological investigation of landslides and the theoretical background of landslide stability coefficient prediction.

Steep End-Slope Mining and Slope Stability of Extremely Thick Inclined Coal Seam Open-Pit Mine

Considering the characteristics of extremely thick inclined open-pit coal mine with large amount under end slope, large end-slope height, and long exposure time, it is important to study the slope stability research during open-pit mining. This study takes the whole process of excavation descending and steep end-slope mining of an extremely thick inclined open-pit mine as the background. The slope stability factor of the end slopes were calculated for each stage of mining with different coal seam thicknesses by using the strength reduction method. The slope data, such as vertical stress, horizontal stress, and increment of maximum shear strain, are analyzed. The results show that the vertical stress and stability factor are decreasing throughout the mining stage. The horizontal stress shows a pattern of increasing and then decreasing in the excavation descending and steep end-slope mining. The greater the thickness of coal seam, the less the stability of the slope.

Effect of Slope on Landslide Potential at Kuranji Watershed

The Kuranji watershed is one of the largest watersheds in the city of Padang. Several landslides and floods have been reported in this area. Many factors cause landslides, both natural and non-natural factors. One of the natural factors that cause landslides is the topography/slope condition. The sloping/steep topography in the downstream area of the Kuranji watershed causes a high potential for landslides in this area. Landslides occur due to balance disturbances that cause the movement of soil and rock masses from a higher place to a lower place. Therefore, it is necessary to analyze slope stability to determine the effect of slope conditions on the potential for landslides. In this study, an analysis of the potential for slopes stability was carried out using the Ordinary Method of Slices. The analysis is carried out by making different slopes so that the value of the safety factor will be obtained from each slope. The slope variation used in this study is the ratio of height to slope width of 1:5, 1:4, 1:3, 1:2, 1:1, 1:0.5, 1:0.25. The results showed that the smaller the slope and the height of the slope, the more stable the slope will be, on the contrary, the larger the slope, the more unstable the slope. This can be assessed from the value safety factor (SF) of slope stability which is obtained from the calculation, which is getting smaller as the slope and height of the slope decrease.

Numerical Simulation of the Stability of a Cutting Slope and Study on Its Reinforcement Scheme

Analyzing the stability of the slope and studying the reinforcement scheme can reduce ecological disasters, improve the ecological environment, and protect people’s lives and property. In this paper, taking the left side slope of ZK100 + 860∼+975 cutting of the Huizhou‐Qingyuan section of the Shantou‐Zhanjiang Expressway as an example, based on the strength reduction method (SRM), the stability of the slope under different conditions (natural conditions, unsupported excavation conditions, rainstorm conditions, and reinforcement conditions) is analyzed by using finite element software. The results show that the slope was almost stable before excavation, and the safety factor of slope stability decreases due to excavation, so it is in an unstable state. Rainwater has a great influence on the stability of the slope. The damage to the slope is deepened, and the stability safety factor is decreased under the rainstorm condition. The stability safety factor of the slope has increased by 24.3% after the reinforcement of the anchor rod and anchor cable, and the slope is in a stable state. It can be seen that the anchor rod and anchor cable can effectively control the deformation of the slope and have a good reinforcement effect.

ANALISIS STABILITAS LERENG MENGGUNAKAN APLIKASI PLAXIS 8.2 DENGAN PERKUATAN DINDING PENAHAN TANAH

The high embankment is one of the most common problems in toll road construction projects. Embankment aims to equalize the ground elevation. Higher the embankment, the greater the load will be received by the subgrade. So, it is necessary to analyze the stability of the embankment to determine condition of stability and some important safety factor (SF) values. Slope stability planning was carried out using reinforced retaining wall with a height of 9,5 m and a width of 5,7 m. Soil foundation type was cohesive soil (clay) and the embankment soil type used non-cohesive soil (sandy). Several SF values are obtained by using Plaxis 8.2, such as: the safety factor (SF) of slope stability without and with reinforcements are 1,23 and 1,59, respectively; SF of shear stability is 2,24; SF of overturning stability of 2,1; and SF of bearing capacity is 3,36.

Prediction of safety factors for slope stability: comparison of machine learning techniques

Prediction of safety factors for slope stability: comparison of machine learning techniques

Numerical Simulation Analysis of Slope Instability and Failure of Limestone Mine in Weibei

Weibei area is the largest limestone resource area in Shaanxi Province, which is an important boundary to distinguish the climate difference between the south and the north of China, and also a significant ecological safety protection barrier in the northwest of China. The complex geological environment and harsh environment make the mining area have serious geological disaster hidden danger. Based on the site engineering geological data of typical limestone quarry slope in Weibei, this paper constructs a three-dimensional geological model, uses FLAC3D software to simulate excavation, and analyzes the stress and strain law of the quarry slope. SlopeLE software was used to analyze the safety factor of slope stability and the potential slip surface before and after taking reinforcement measures. The results show the following: (1) Limestone is the main rock component of the mine, followed by mudstone. The joint and fissure are developed, the rock mass is broken, and the hidden danger of engineering geological disaster is high. (2) There is a sliding trend in both sides during excavation, and the maximum vertical displacement is 2.1 cm. (3) If the slope is reinforced according to the design scheme, the slope stability safety factor will be increased from 1.062 to 1.203 in a stable state, which greatly improves the stability of the slope and provides a guarantee for human and financial resources.

Failure Mode and Characteristics of Expansive Rock and Influencing Factors of High Slope Stability

Failure Mode and Characteristics of Expansive Rock and Influencing Factors of High Slope Stability

Stability Analysis of Rock Slope Based on Improved Principal Component Analysis Model: Taking Fuwushan Slope as an Example

Aiming at the problems of low accuracy, low efficiency, and many parameters required in the current calculation of rock slope stability, a prediction model of rock slope stability is proposed, which combines principal component analysis (PCA) and relevance vector machine (RVM). In this model, PCA is used to reduce the dimension of several influencing factors, and four independent principal component variables are selected. With the help of RVM mapping the nonlinear relationship between the safety factor of slope stability and the principal component variables, the prediction model of rock slope stability based on PCA-RVM is established. The results show that under the same sample, the maximum relative error of the PCA-RVM model is only 1.26%, the average relative error is 0.95%, and the mean square error is 0.011, which is far lower than that of the RVM model and the GEP model. By comparing the results of traditional calculation method and PCA-RVM model, it can be concluded that the PCA-RVM model has the characteristics of high prediction accuracy, small discreteness, and high reliability, which provides reference value for accurately predicting the stability of rock slope.

Finite element analysis of a slope stability by incrementally increasing the mobilised principal stress deviator

ABSTRACT The assessment of slope stability factor by a FE analysis using the shear strength reduction method (SRM) enjoys several advantages and owns many shortcomings. As an alternative, a new FE approach called stress deviator increasing method (SDIM) is proposed. By means of a factor termed Mohr’s circle expansion factor, the new approach assesses the slope stability by incrementally increasing the mobilised principal stress deviator until the soil failure is reached. The numerical procedure is based then on a rigorous formulation as it preserves the definition of the safety factor consistent with that of LEM and maintains the progressive development of the shear stress on same plane on which the shear strength will occur at failure. The proposed method deals with the actual material by using the real strength parameters and rather than those reduced by a factor. The results of SDIM encoded in a computer code called were thoroughly assessed against those of both SRM and LEM using several slope examples involving and purely cohesive soils. Results of comparison encompassing factor of safety along with plastic strain distributions showed the reliability and the strength of the present method.

Sensitivity Analysis of Anchored Slopes under Water Level Fluctuations: A Case Study of Cangjiang Bridge—Yingpan Slope in China

This paper presents an improved slope stability sensitivity analysis (ISSSA) model that takes anchoring factors into consideration in umbrella-anchored sand and clay slopes under reservoir water level fluctuation. The results of the ISSSA model show that the slope inclination and the layout density of anchors are the main controlling factors for sand slope stability under fluctuation of the water level, while the slope inclination and water head height are the main controlling factors for slope stability in the Cangjiang bridge—Yingpan slope of Yunnan province in China. Moreover, there is an optimum anchorage angle, in the range of 25–45 degrees, which has the greatest influence on slope stability. The fluctuation of the reservoir water level is an important factor that triggers slope instability; in particular, a sudden drop in the surface water level can easily lead to landslides; therefore, corresponding measures should be implemented in a timely manner in order to mitigate landslide disasters.

Early mitigation of landslide prone areas with remote sensing and analysis of slope stability in ampera, south jayapura district, papua province

Ampera, located in the eastern slope of Cycloop Mountains, Papua Province had a landslide disaster on March 17, 2019. Landslides in Ampera is caused by the steep slope. Landslides occur due to lack of early mitigation which results in material loss and death. Early mitigation was carried out by remote sensing aimed at mapping landslide-prone areas in Ampera. The determination of landslide-prone areas is based on several parameters and weighting of remote sensing. The parameters are based on the provisions made by the author with secondary data. Weighting is used based on the results AHP method. Parameters and weighting using rainfall (44%), slope gradient (31%), NDVI (15%), slope water density (7%), and road density (3%). This parameter is processed into raster data which is then combined with weighting. The results, Ampera has a moderate to high vulnerability for landslides. Three high vulnerability area was made a modeling incision to determine safety factor value for slope stability. Modeling was done using characteristics of Podzolic Soil type, obtained from the Soil Distribution Map of Papua Province. Based on the results of the modeling, the average value of the safety factor of slope stability in three areas with high vulnerability is 0.5 (unstable).

Propagation of frontally confined subaqueous landslides: Insights from combining geophysical, sedimentological, and geotechnical analysis

Subaquatic mass movements are common in marine and lacustrine environments, but due to their barely predictable nature, direct observations of these processes are limited so that knowledge is only indirectly obtained by investigating the resulting mass-transport deposits (MTDs). Most research focuses on the most common frontally emergent slides, fast-moving events able to generate turbidity currents and tsunamis. Geohazards of frontally confined slides and mechanisms behind their typical fold-and-thrust deformation structures are however still poorly understood.We investigate frontally confined MTDs in Lake Lucerne (Switzerland) by integrating bathymetric and high-resolution seismic data with geotechnical information derived from in situ Cone Penetrometer Tests and short core analysis. Investigated MTDs consist of three units: i) a mass-slide deposit, located at the base of the slope consisting of a coherent slope sequence, ii) a fold-and-thrust system developed in basin sediments, and iii) an overrunning mass flow deposit, consisting of remolded slope sediments. The deformed and thrusted basin sediments show higher undrained shear strength compared to the undisturbed basin sequence. We propose that this strengthening is caused by lateral compression leading to fluid expulsion in the high-plasticity basin sediments by the bulldozing sliding mass. Relative kinematic indicators document that the fold-and-thrust deformation structures occur rapidly. Thus, they should be considered in tsunami hazard analysis. Furthermore, our data highlight that the slope angle of the gliding surface and basin topography are key controlling factors for slope stability and propagation of basin-plain deformations, respectively. Our integrated study supports and refines propagation models proposed in marine environments, revealing the potential of investigating smaller-scale easier-to-access MTDs in lakes.

Stability Analysis of Rock-soil Mixture Slope

This research provides a method of random generation of Soil-rock Mixture (SRM) model depends on digital imaging technology and rock stone database technology. With processed rock shape diagrams, database of rock shape had been built and a method of random generation depend on this database had been provided. The SRM backfilled slope models were generated with random generation method. Couples of SRM slope models had been simulated with ABAQUS CAE to study the stability of SRM slope with different parameters variations. The influence of block stones on the slope stability is main caused by rock stones’ slipresistance effect. When the stone content is 40%-50%, the block stones gradually contact with each other and form a framework. The safety factor gradually increases. The spatial distribution of rock stones at the foot of the slope has the most obvious influence on the stability of SRM slope. With the increase of maximum block size, the slope stability decreases firstly and then increase. The sliding resistance effect is the key factor of the SRM slope stability. Aggregation of small size stones or large size stones can change the shape of the sliding surface and have great influence on the stability of the slope.