scholarly journals Analysis of Slope Stability with Imprecise Soil Properties Using Uncertain Sets

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xuejun Zhou ◽  
Jie Li ◽  
Zhibing Liu ◽  
Yi Tang
Keyword(s):  
Slope Stability ◽  
Soil Properties ◽  
Safety Factor ◽  
Unit Weight ◽  
Membership Functions ◽  
Stability Of Slopes ◽  
Operational Laws ◽  
Layered Slope ◽  
The Stability ◽  
Parameter Values

There are many uncertainties with respect to the assessment of slope stability, and those associated with soil properties should be given particular attention. The uncertainty theory provides an alternative to treat these uncertainties using parochial cognitive sources. A novel methodology is proposed to evaluate the stability of slopes based on an uncertain set. The soil properties involved in the deterministic methods, i.e., shear strength parameters and unit weight, are expressed as uncertain sets, and their membership functions can be assumed to be triangular or trapezoidal for a homogeneous or two-layered slope, respectively. The parameter values of membership functions are designed according to the means and variations of the soil properties, and then the expected safety factor can be calculated through the operational laws. Two numerical examples including a homogeneous slope and a two-layered slope illustrate the suitability of the proposed methodology. The relationship between the variation in the safety factor and the changes in the soil properties is investigated; moreover, the determination of the parameter values of membership is also discussed.

scholarly journals Groundwater Fluctuation Simulation in Pagelaran Landslide, Cianjur, Indonesia

2020 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Twin Hosea Widodo Kristyanto
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Groundwater Level ◽  
Slip Surface ◽  
Unit Weight ◽  
Undisturbed Soil ◽  
Actual Position ◽  
Groundwater Fluctuation ◽  
Artesian Wells ◽  
The Stability

Pagelaran is one of area in Southern Part of Cianjur. This area has high susceptibility of landslide. One of landslide in Pagelaran, which happened on December 2014, has destroyed 13 houses and damaged vital road along 200 m. A year later, it started to conduct observation regarding the slope. The research aimed to know the role of groundwater level fluctuation in Pagelaran Landslide. The geometry of slope and its slip surface were determined using Electrical Resistivity Tomography. The actual groundwater level was determined by measuring it from surrounding artesian wells. Parameters angle of friction, cohesion, and unit weight were obtained from laboratory tests toward undisturbed soil samples. These data were used for analyzing the actual slope stability condition. Then it was conducted the simulation of slope stability in accordance with fluctuations of groundwater level. The simulation was done by raising the groundwater level with range of 0.5 m. The results showed that the actual slope stability was in critical condition with the value of safety factor 1.044. It also showed that slope stability waned as rising of groundwater level. The value of safety factor was reduced by an average of 0.034 in each 0.5 m up of groundwater level until it became failure (FS<1) when the groundwater level was 0.95 m above the actual position. Therefore, it can be concluded that the position of groundwater level played a role toward the stability of slope in Pagelaran. The rising 0.5 m of groundwater level position will reduce the slope safety factor by 0.034. The slope will become failure if the position of groundwater level rises by 0.95 meter from the actual position. To prevent the rising of groundwater level in rainy season, which can trigger landslide, it can be attached pipes along the slope body to flow the groundwater through them.

scholarly journals Application of Harmony Search Algorithm to Slope Stability Analysis

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1250
Author(s):  
Sina Shaffiee Haghshenas ◽  
Sami Shaffiee Haghshenas ◽  
Zong Woo Geem ◽  
Tae-Hyung Kim ◽  
Reza Mikaeil ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Search Algorithm ◽  
Limit Equilibrium ◽  
Harmony Search ◽  
Harmony Search Algorithm ◽  
Slope Stability Analysis ◽  
Unit Weight ◽  
Slope Safety

Slope stability analysis is undoubtedly one of the most complex problems in geotechnical engineering and its study plays a paramount role in mitigating the risk associated with the occurrence of a landslide. This problem is commonly tackled by using limit equilibrium methods or advanced numerical techniques to assess the slope safety factor or, sometimes, even the displacement field of the slope. In this study, as an alternative approach, an attempt to assess the stability condition of homogeneous slopes was made using a machine learning (ML) technique. Specifically, a meta-heuristic algorithm (Harmony Search (HS) algorithm) and K-means algorithm were employed to perform a clustering analysis by considering two different classes, depending on whether a slope was unstable or stable. To achieve the purpose of this study, a database made up of 19 case studies with 6 model inputs including unit weight, intercept cohesion, angle of shearing resistance, slope angle, slope height and pore pressure ratio and one output (i.e., the slope safety factor) was established. Referring to this database, 17 out of 19 slopes were categorized correctly. Moreover, the obtained results showed that, referring to the considered database, the intercept cohesion was the most significant parameter in defining the class of each slope, whereas the unit weight had the smallest influence. Finally, the obtained results showed that the Harmony Search algorithm is an efficient approach for training K-means algorithms.

scholarly journals Hydro-Mechanical Effects of Several Riparian Vegetation Combinations on the Streambank Stability—A Benchmark Case in Southeastern Norway

2021 ◽  
Vol 13 (7) ◽  
pp. 4046
Author(s):  
Vittoria Capobianco ◽  
Kate Robinson ◽  
Bjørn Kalsnes ◽  
Christina Ekeheien ◽  
Øyvind Høydal
Keyword(s):  
Slope Stability ◽  
Methodological Approach ◽  
River System ◽  
Flood Management ◽  
Natural State ◽  
Mechanical Reinforcement ◽  
Climate Conditions ◽  
Salix Caprea ◽  
Stability Of Slopes ◽  
The Stability

Vegetation can be used as a nature-based solution (NBS) to restore rivers and mitigate water-triggered processes along streambanks. Roots are well known to improve the overall stability of slopes through hydro-mechanical reinforcement within the rooted zone. Vegetation-based solutions require the selection of species that are most suitable for specific locations, and they are aimed at restoring the natural state and function of river systems in support of biodiversity, flood management, and landscape development. Selecting a combination of different species along different zones of the riverbank can improve the conditions for the river system with regard to biodiversity and stability. Therefore, more studies are needed to investigate how the combination of a variety of different plant species can improve the stability of the riverbank. This paper presents a methodological approach for slope stability modeling including vegetation as well as the results obtained from a series of slope stability calculations adopting the proposed methodology. The analyses were carried out for critical shallow (≤3 m deep) shear planes of ideal benchmark slopes covered with four different plant combinations—(i) only grass, (ii) grass and shrubs, (iii) only trees, and (iv) trees, shrubs, and grass—for species typically found along streams in southeastern Norway. In this desk study, two types of tree species were selected, namely Norway spruce (Picea abies) and Downy birch (Betula pubescens). The Goat willow (Salix caprea) was selected as a shrub, while a common mixed-grass was chosen as grass. Vegetation features were obtained from the literature. The methodology was used for two main cases: (1) considering only the mechanical contribution of vegetation and (2) considering both the hydrological and mechanical reinforcement of vegetation. The main outcome of the numerical modeling showed that the purely mechanical contribution of vegetation to slope stability could not be decoupled from the hydrological reinforcement in order to have a realistic assessment of the roots improvement to the stability. The most critical shear surfaces occurred below the rooted zone in all cases, and the best performance was obtained using the combinations including trees. Considering the typical climate conditions in Norway, the hydro-mechanical reinforcement was most effective in the spring and for combinations including low height vegetation (i.e., grass and shrubs). The study concludes that a mixed combination of vegetation (trees, shrubs, and grass) is the most suitable for reaching the highest hydro-mechanical reinforcement of streambanks, together with erosion protection and boosting the ecosystem biodiversity. The current study can help practitioners determine which vegetation cover combination is appropriate for improving the current stability of a streambank with restoration practices.

Influence of cross correlation between soil parameters on probability of failure of simple cohesive and c-ϕ slopes

2016 ◽  
Vol 53 (5) ◽  
pp. 839-853 ◽  
Author(s):  
Sina Javankhoshdel ◽  
Richard J. Bathurst
Keyword(s):  
Slope Stability ◽  
Soil Properties ◽  
Cross Correlation ◽  
Friction Angle ◽  
Probability Of Failure ◽  
Unit Weight ◽  
Soil Parameters ◽  
Design Charts ◽  
Soil Slopes ◽  
Cross Correlations

This paper focuses on the calculation of probability of failure of simple unreinforced slopes and the influence of the magnitude of cross correlation between soil parameters on numerical outcomes. A general closed-form solution for cohesive slopes with cross correlation between cohesion and unit weight was investigated and results compared with cases without cross correlation. Negative cross correlations between cohesion and friction angle and positive cross correlations between cohesion and unit weight, and friction angle and unit weight were considered in the current study. The factors of safety and probabilities of failure for the slopes with uncorrelated soil properties were obtained using probabilistic slope stability design charts previously reported by the writers. Results for cohesive soil slopes and positive cross correlation between cohesion and unit weight are shown to decrease probability of failure. Probability of failure also decreased for increasing negative cross correlation between cohesion and friction angle, and increasing positive correlation between cohesion and unit weight, and friction angle and unit weight. Probabilistic slope stability design charts presented by the writers in an earlier publication are extended to include cohesive-frictional (c-[Formula: see text]) soil slopes with and without cross correlation between soil input parameters. An important outcome of the work presented here is that cross correlation between random values of soil properties can reduce the probability of failure for simple slope cases. Hence, previous probabilistic design charts by the writers for simple soil slopes with uncorrelated soil properties are conservative (safe) for design. This study also provides one explanation why slope stability analyses using uncorrelated soil properties can predict unreasonably high probabilities of failure when conventional estimates of factor of safety suggest a stable slope.

scholarly journals ANALISIS STABILITAS LERENG MENGGUNAKAN SOFTWARE PLAXIS 8.6 DENGAN DINDING PENAHAN TANAH (RETAINING WALL) (STUDI KASUS RUAS JALAN NASIONAL BANDA ACEH-MEDAN STA 83+135 GUNUNG SEULAWAH)

2018 ◽  
Vol 1 (3) ◽  
pp. 76-82
Author(s):  
Wihardi Wihardi ◽  
Munirwansyah Munirwansyah ◽  
Sofyan M. Saleh
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Retaining Wall ◽  
Road Construction ◽  
Local Area ◽  
Traffic Load ◽  
Road Infrastructure ◽  
The Road ◽  
The Stability ◽  
Banda Aceh

Road infrastructure is very important and is a key enabler for the economy. If the road infrastructure was damaged or had various problems such as sliding, the movement of goods and passengers will be hampered and delayed to the acceleration of development in the local area. The landslide and movement of groundwater is a problem that often occurs repeatedly on some streets. Therefore, it is necessary to study the strengthening of the slopes at the bottom of the road construction with retaining wall. This study aims to analyze slope stability by getting numbers Safety Factor (FK). The analysis is used to analyze the stability of slopesusing the finite element method with the help of software Plaids, The scope of this review includes the calculation of slope stability at the national road from Banda Aceh - Medan Sta. 83 + 185 Mount Selawah. The results of slope stability analysis on the existing condition by using Plaxis software at the point of a review is not safe (FK 1.25). Thus, it is done handling the retaining wall, installation of anchors. Based on the analysis of slope stability after being given the strengthening of the slopes with a retaining wall and the installation of anchors using Plaxis software under the influence of traffic load in an unsafe condition (FK 1.25). Then additional handling is done by changing the angle of the slope so that the value of the safety factor (FK) 1.25.

scholarly journals Influence of parameters of retaining walls and loose soils on the stability of slopes in the new construction of residential complexes

2020 ◽  
pp. 65-75
Author(s):  
Liudmyla Skochko ◽  
Viktor Nosenko ◽  
Vasyl Pidlutskyi ◽  
Oleksandr Gavryliuk
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Cross Sections ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Natural State ◽  
Soil Parameters ◽  
Stability Of Slopes ◽  
The Stability ◽  
Stage 1

The stability of the slope in the existing and design provisions is investigated, the constructive decisions of retaining walls on protection of the territory of construction of a residential complex in a zone of a slope are substantiated. The stability of the slope when using rational landslide structures is estimated. The results of the calculation of the slope stability for five characteristic sections on the basis of engineering-geological survey are analyzed. For each of the given sections the finite-element scheme according to the last data on change of a relief is created. The slope was formed artificially by filling the existing ravine with construction debris from the demolition of old houses and from the excavation of ditches for the first houses of the complex. Five sections along the slope are considered and its stability in the natural state and design positions is determined. Also the constructive decisions of retaining walls on protection of the territory of construction of a residential complex as along the slope there are bulk soils with various difference of heights are substantiated. This requires a separate approach to the choice of parameters of retaining walls, namely the dimensions of the piles and their mutual placement, as well as the choice of the angle of the bulk soil along the slope. The calculations were performed using numerical simulation of the stress-strain state of the system "slope soils-retaining wall" using the finite element method. An elastic-plastic model of soil deformation with a change in soil parameters (deformation module) depending on the level of stresses in the soil is adopted. Hardening soil model (HSM) used. Calculations of slope stability involve taking into account the technological sequence of erection of retaining walls and modeling of the phased development of the pit. The simulation was performed in several stages: Stage 1 - determination of stresses from the own shaft, Stage 2 - assessment of slope stability before construction, Stage 3 - installation of retaining wall piles, Stage 4 - assessment of slope stability after landslides. Based on these studies, practical recommendations were developed for the design of each section of the retaining wall in accordance with the characteristic cross-sections.

scholarly journals Fragility Curves for Slope Stability of Geogrid Reinforced River Levees

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2615
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Soil Properties ◽  
Composite Structures ◽  
Fragility Curves ◽  
Control Measures ◽  
Total Uncertainty ◽  
Earthen Structures ◽  
The Stability ◽  
Northern Croatia

When constructing flood protection structures such as river levees, oftentimes due to various factors engineers must design composite structures, i.e., reinforced earthen structures which comply with all the stability criteria. The most common way of reinforcing such structures is the usage of geosynthetics, or mostly geogrids when talking about stability. Since geosynthetics are man-made materials produced in a controlled environment and go through quality control measures, their characteristics contain a negligible amount of uncertainty compared to natural soils. However, geosynthetic handling, their installation in the levee, and their long-term degradation can all have significant effects of variable magnitude on geosynthetic characteristics. These effects and their variability can be considered as random variables, which can then be used in probabilistic analyses together with soil properties. To investigate the effects of the geogrid’s resistance variability on slope stability compared to soil properties variability, probabilistic analyses are conducted on a river levee in northern Croatia. It is found that the geogrid’s variability generally has very little effect on the total uncertainty compared to the friction angle’s variability, but out of the three geogrid layers used the top grid has the most influence.

scholarly journals Pengaruh Biopolimer Pada Stabilitas Lereng Swelling soil

2021 ◽  
Vol 5 (3) ◽  
pp. 307-316
Author(s):  
Dewi Amalia ◽  
Bagus Guritno ◽  
Geni Firuliadhim
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Soil Type ◽  
Analysis Program ◽  
Swelling Soil ◽  
The Difference ◽  
The Stability ◽  
Cracked Soil

Many studies have begun to develop the concept of cracked soil. The results of research related to cracked soil are able to answer the irregularities that occur, such as the difference in the results of the stability analysis which is considered safe with the conventional bishop method, while the conditions in the field are landslides. Swelling soil is soil that is susceptible to changes in water content. This type of soil is very prone to cracking. To build infrastructure on the swelling soil type, an improvement must be made, one of which is by mixing the swelling soil with biopolymer. The results of this biopolymer mixing are then modeled in the New Slope Stability Analysis Program (NSSAP) 1.0 which refers to the concept of cracked soil. From the analysis, it was found that the slope safety factor before improvement with biopolymer was 0.305 and the safety factor after improvement with biopolymer was 2.006. From the results of this study, it can be seen that the role of biopolymers in stabilizing swelling soil is quite large, which is around 558%.

scholarly journals Stability Assessment and Optimization Design of Lakeside Open-Pit Slope considering Fluid-Solid Coupling Effect

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Wenchen Fan ◽  
Ping Cao ◽  
Ke Zhang ◽  
Kaihui Li ◽  
Chong Chen
Keyword(s):  
Slope Stability ◽  
Water Level ◽  
Lake Water ◽  
Optimization Design ◽  
Great Influence ◽  
Water Levels ◽  
Open Pit ◽  
Stability Of Slopes ◽  
The Stability ◽  
Slope Design

Chengmenshan copper mine, located at Jiujiang city in the Jiangxi Province, is a rarely lakeside open-pit mine in China. Since the open-pit is very close to Sai Lake, the seasonally changed water level and the distance between lake and slope have great influence to the stability of open-pit slope. Based on the drill data and geological sections, a numerical model of the slope is built. With the fluid-mechanical interaction associated, the stability of the slopes is numerically analyzed, in which different lake water levels and lake-slope distances are taken into consideration. The comparative analysis shows that a larger lake-slope distance can promise better slope stability and weaken the sensitivity of slope stability to water. The stability of slopes with different heights is analyzed to find that the stability weakens and the sensitivity is enhanced with the height increasing. To the most serious situation, the slope height and the lake water level being 238 m and 17.2 m, respectively, theFsvalue equals 1.18945 which is extremely closed to the allowable safety factor of 1.20 for slope design. According to the minimumFsfor slope design, the minimum distance between lake and open-pit slope is found to be 60 m.

scholarly journals Wildfire Impacts on Slope Stability Triggering in Mountain Areas

Geosciences ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 417 ◽  
Author(s):  
Abbate ◽  
Longoni ◽  
Ivanov ◽  
Papini
Keyword(s):  
Slope Stability ◽  
Debris Flows ◽  
Degree Of Saturation ◽  
Critical Conditions ◽  
Vegetation Coverage ◽  
Large Variability ◽  
Stability Of Slopes ◽  
Wildfire Effects ◽  
The Stability

Landslides over steep slopes, floods along rivers plains and debris flows across valleys are hydrogeological phenomena typical for mountain regions. Such events are generally triggered by rainfall, which can have large variability in terms of both its intensity and volume. Furthermore, terrain predisposition and the presence of some disturbances, such as wildfires, can have an adverse effect on the potential risk. Modelling the complex interaction between these components is not a simple task and cannot always be carried out using instability thresholds that only take into account the characteristics of the rainfall events. In some particular cases, external factors can modify the existing delicate equilibrium on the basis of which stability thresholds are defined. In particular, events such as wildfires can cause the removal of vegetation coverage and the modification of the soil terrain properties. Therefore, wildfires can effectively reduce the infiltration capacity of the terrain and modify evapotranspiration. As a result, key factors for slope stability, such as the trend of the degree of saturation of the terrain, can be strongly modified. Thus, studying the role of wildfire effects on the terrain’s hydrological balance is fundamental to establish the critical conditions that can trigger potential slope failures (i.e., shallow landslides and possible subsequent debris flows). In this work, we investigate the consequences of wildfire on the stability of slopes through a hydrological model that takes into account the wildfire effects and compare the results to the current stability thresholds. Two case studies in the Ardenno (IT) and Ronco sopra Ascona (CH) municipalities were chosen for model testing. The aim of this paper is to propose a quantitative analysis of the two cases studies, taking into account the role of fire in the slope stability assessment. The results indicate how the post-fire circumstances strongly modify the ability of the terrain to absorb rainfall water. This effect results in a persistently drier terrain until a corner point is reached, after which the stability of the slope could be undermined by a rainfall event of negligible intensity.

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