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 Slope Stability Evaluation of Geosynthetic Reinforced Soil

2019 ◽  
Vol 8 (4) ◽  
pp. 7143-7147
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Friction Angle ◽  
Calculation Model ◽  
Reinforced Soil ◽  
Unit Weight ◽  
Soil Parameters

The slippery of natural slope is sometimes ruled by combination of soil parameters and earthquake characteristics. Geotextiles could be a reinforcing materials and an application in numerous areas still as in geotechnical application to supply additional lateral restraint and forestall the high rise hill from failure. The analysis was aimed to analyze slope stability analysis, strengthened the Finite slope with non-woven geotextiles. The modal of hill was created within the SLOPE/W software system of GeoStudio that is predicated on limit equilibrium of slope analysis. The results of issue of safety square measure compared while not and with use of geotextiles in several layers. The issue of safety of slope failure will increase from three.437M to 9.978M victimization 3 layers of geotextiles at optimum height. Thus, this study confirms that the non-woven geotextiles may be applied in slope so as to enhance the soundness of natural or mam-made slope. During this regard, special stress is given to the sensitivity of the Calculation model input parameters like friction angle, cohesion, Pore water pressure and unit weight of soil that ought to contribute to raising awareness regarding these problems, as a requirement to create the proper selections and optimum technical resolution during this space.

scholarly journals Inverse distance weighting interpolated soil properties and their related landslide occurrences

2018 ◽  
Vol 195 ◽  
pp. 03013 ◽  
Author(s):  
Purwanto B. Santoso ◽  
Yanto ◽  
Arwan Apriyono ◽  
Rani Suryani
Keyword(s):  
Internal Friction ◽  
Slope Stability ◽  
Soil Properties ◽  
Hard Rock ◽  
Friction Angle ◽  
Inverse Distance Weighting ◽  
Central Java ◽  
Soil Cohesion ◽  
Distance Weighting ◽  
Inverse Distance

The causes of landslides can be categorized into three factors: climate, topographic, and soil properties. In many cases, thematic maps of landslide hazards do not involve slope stability analyses to predict the region of potential landslide risks. Slope stability calculation is required to determine the safety factor of a slope. The calculation of slope stability requires the soil properties, such as soil cohesion, the internal friction angle and the depth of hard-rock. The soil properties obtained from the field and laboratory investigation from the western part of Central Java were interpolated using Inverse Distance Weighting (IDW) to estimate the unknown soil properties in the gridded area. In this research, the IDW optimum parameter was determined by validation toward the percent bias. It was found that the IDW interpolation using higher weighting factor corresponds with a higher percent bias in case of the depth of hard-rock and soil cohesion, while the opposite was found for the internal friction angle. Validation to landslide incidents in western parts of Central Java shows that the majority of landslide incidents occur at depths of hard rock of 6 m-8 m, at soil cohesions of 0.0 kg/cm2-0.2 kg/cm2, and at internal friction angles of 30°-40°.

Structural Reliability of Free Spanning Pipelines

2014 ◽  
Author(s):  
F. Van den Abeele ◽  
F. Boël ◽  
J.-F. Vanden Berghe
Keyword(s):  
Soil Properties ◽  
Fatigue Damage ◽  
Structural Reliability ◽  
Flow Direction ◽  
Unit Weight ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Span Length ◽  
Form Analysis ◽  
Reliability Method

When installing subsea pipelines on an uneven seabed, the free spans can be vulnerable to fatigue damage caused by vortex induced vibrations (VIV). Indeed, even moderate currents can induce vortex shedding, alternately at the top and the bottom of the pipeline, at a rate determined by the flow velocity. Each time a vortex sheds, a force is generated in both the in-line and cross-flow direction, causing an oscillatory multi-mode vibration. This vortex induced vibration can give rise to fatigue damage of submarine pipeline spans, especially in the vicinity of the girth welds. Traditional design for VIV is recommended in DNV-RP-F105, which limits the allowable free span length and implies whether (and when) seabed interventions are required. The traditional DNV-RP-F105 design method is based on a semi-empirical approach, where the allowable span length depends on the pipe properties (diameter, wall thickness, coating, steel SN_curves, …), the sea state (current velocity, wave induced velocity and period) and the soil conditions (submerged unit weight, undrained shear strength, bearing capacity,…). All these input parameters, however, exhibit a certain extent of scatter and uncertainty. This paper presents a risk based evaluation of free spans, by applying the principles of structural reliability theory to the problem of long free spanning pipelines subjected to VIV. First, a fully deterministic on-bottom roughness analysis is performed to introduce numerical tools for free span analysis. Then, a sensitivity analysis on soil parameters is presented to show significant influence of soil properties on free span predictions. To study the implications of uncertainty in soil properties, a First Order Reliability Method (FORM) analysis is presented at the end of this paper, where the soil properties are introduced as stochastic variables.

Practical reliability analysis of slope stability by advanced Monte Carlo simulations in a spreadsheet

2011 ◽  
Vol 48 (1) ◽  
pp. 162-172 ◽  
Author(s):  
Yu Wang ◽  
Zijun Cao ◽  
Siu-Kui Au
Keyword(s):  
Monte Carlo ◽  
Slope Stability ◽  
Spatial Variability ◽  
Soil Properties ◽  
Reliability Analysis ◽  
Slip Surface ◽  
Probability Of Failure ◽  
Critical Slip Surface ◽  
Microsoft Excel ◽  
Mcs Method

This paper develops a Monte Carlo simulation (MCS)-based reliability analysis approach for slope stability problems and utilizes an advanced MCS method called “subset simulation” for improving efficiency and resolution of the MCS at relatively small probability levels. Reliability analysis is operationally decoupled from deterministic slope stability analysis and implemented using a commonly available spreadsheet software, Microsoft Excel. The reliability analysis spreadsheet package is validated through comparison with other reliability analysis methods and commercial software. The spreadsheet package is then used to explore the effect of spatial variability of the soil properties and critical slip surface. It is found that, when spatial variability of soil properties is ignored by assuming perfect correlation, the variance of the factor of safety (FS) is overestimated, which may result in either over (conservative) or under (unconservative) estimation of the probability of failure (Pf = P(FS < 1)). When the spatial variability of soil properties is considered, the critical slip surface varies spatially and such spatial variability should be properly accounted for. Otherwise, the probability of failure can be significantly underestimated and unconservative.

Analysis of Influence Factors of Slope Stability

2012 ◽  
Vol 256-259 ◽  
pp. 34-38
Author(s):  
Shu Lian Wen ◽  
Hai Bin La ◽  
Chang Zhong Wang
Keyword(s):  
Slope Stability ◽  
Influence Factors ◽  
Friction Angle ◽  
Unit Weight ◽  
Calculation Methods ◽  
Internal Factors ◽  
Factors Affecting ◽  
Method Of Calculation ◽  
The Relationship ◽  
Optimal Designing

Slope stability is affected by many factors, their effects on the slope stability may be big or small. Along with continuous improvement of the various calculation methods, it is more important to identify the main influencing ratio factors in the process of analyzing the slope stability than to select the method of calculation .Therefore the paper analyzed the main internal factors, calculated to get five curves that showed the relationship between these influence factors and the safety factor, The results show that unit weight of soil, cohesion and internal friction angle are the main factors affecting slope stability. Then, it can take corresponding measures in the process of targeting and optimal designing slopes in order to achieve security, economic and efficient goals.

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 SOIL SHEAR STRENGTH PARAMETER ANALYSIS BASED ON BEHAVIOR ANALYSIS OF LANDSLIDE CASE

UKaRsT ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 163
Author(s):  
Dyah Wahyu Apriani ◽  
Umar Mustofa ◽  
Rachmad Hidayat
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Slope Failure ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Unit Weight ◽  
Strength Parameter ◽  
Soil Parameters ◽  
Soil Shear Strength ◽  
Reverse Analysis

Slope failure is a complex event. It can provide useful information about the condition of soil parameters on the failed slope in the same way it can provide an opportunity to evaluate the stability of other slopes. To evaluate the occurence of slope failure, unit weight data and shear strength properties of soil are needed, as well as methods of analysis including failure mechanisms. One of the methods used to evaluate landslide events is reverse analysis. In this study, reverse analysis was carried out on landslides that occurred on the slopes of D-D 'and F-F' at the Integrated Campus Building of the Institut Teknologi Kalimantan. The finite element method is used to analyze the safety number of the slopes under review. From the results of the reverse analysis, it was obtained that the soil parameters at the time of collapse in the top layer resulted in the value of unit weight (γ) = 20 kN / m2, Cohesion (c) = 2 kPa and Internal friction angle (φ) = 27 ° . Slope failure occured due to an increase in soil volume weight value, as well as a decrease in soil shear strength parameters, namely cohesion and internal friction angle.

Spudcan-Soil Interaction Analysis of a Jack-up Based on Elastic-Plastic Model

2013 ◽  
Vol 401-403 ◽  
pp. 441-445
Author(s):  
Jian Zhang ◽  
Wen Xian Tang ◽  
Hao Qian ◽  
Jun Cao
Keyword(s):  
Interaction Analysis ◽  
Friction Angle ◽  
Unit Weight ◽  
Soil Parameters ◽  
Elastic Plastic ◽  
Foundation Model ◽  
Plastic Components ◽  
Jack Up ◽  
Interaction Behaviors ◽  
Soil Interface

In order to investigate the jack-up spudcan-soil interaction behaviors, numerical simulation and design of experiments (DOE) of a jack-up were presented based on elastic-plastic foundation model, in operating and survival conditions. Spudcan load assessment indexes called RVAB, RHAB and RMAB were put forward by the authors, which were also the responses of the DOE. The results showed that, for both conditions, vertical load V on spudcan A is higher than that on spudcan B, while horizontal load H2 and moment M3 on spudcan A are lower than that on spudcan B. Yield was found on the Spudcan A-soil interface, and the plastic components in survival condition are higher than the ones in operating condition. Friction angle and unit weight are two important soil parameters that have a great effect on the spudcan-soil interaction behaviors.

Effects of Soil Properties Uncertainty on Reliability Index of Slope

2011 ◽  
Vol 250-253 ◽  
pp. 1947-1950
Author(s):  
Bo Han ◽  
Hong Jian Liao ◽  
Hang Zhou Li ◽  
Zheng Hua Xiao
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Slope Stability ◽  
Soil Properties ◽  
Normal Distribution ◽  
Reliability Index ◽  
Random Variables ◽  
Simulation Method ◽  
Soil Parameters ◽  
Monte Carlo Simulation Method

A probabilistic analysis procedure and related algorithms were based on the Monte Carlo simulation method that considers the variability of soil properties in this paper. A homogenous slope example provide insight into the effects of uncertainty due to the variability of soil properties on slope stability .Taking soil parameters cohesion c, friction angle, gravity γ as the basic random variables, the reliability index are calculated using Monte Carlo simulation method taking into account the uncertainties of these basic random variables. The calculated results are compared for four recognized methods of slope stability, which are Ordinary method, simplified Bishop method, simplified Janbu method and Morgenstern Price method. And the influence of soil parameters’ probability distribution model (i.e. the normal distribution and the log–normal distribution), variation coefficient, mean value, correlation between parameters on the reliability index of slope is discussed. The study shows that different soil properties have different influence degree on the reliability index with regard to the slope reliability analysis.

scholarly journals Detrended Multiple Cross-Correlation Coefficient applied to solar radiation, air temperature and relative humidity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea de Almeida Brito ◽  
Heráclio Alves de Araújo ◽  
Gilney Figueira Zebende
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Solar Energy ◽  
Correlation Coefficient ◽  
Air Temperature ◽  
Cross Correlation ◽  
Global Solar Radiation ◽  
Meteorological Variables ◽  
Hourly Data ◽  
Cross Correlations

AbstractDue to the importance of generating energy sustainably, with the Sun being a large solar power plant for the Earth, we study the cross-correlations between the main meteorological variables (global solar radiation, air temperature, and relative air humidity) from a global cross-correlation perspective to efficiently capture solar energy. This is done initially between pairs of these variables, with the Detrended Cross-Correlation Coefficient, ρDCCA, and subsequently with the recently developed Multiple Detrended Cross-Correlation Coefficient, $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2. We use the hourly data from three meteorological stations of the Brazilian Institute of Meteorology located in the state of Bahia (Brazil). Initially, with the original data, we set up a color map for each variable to show the time dynamics. After, ρDCCA was calculated, thus obtaining a positive value between the global solar radiation and air temperature, and a negative value between the global solar radiation and air relative humidity, for all time scales. Finally, for the first time, was applied $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2 to analyze cross-correlations between three meteorological variables at the same time. On taking the global radiation as the dependent variable, and assuming that $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}={\bf{1}}$$DMCx2=1 (which varies from 0 to 1) is the ideal value for the capture of solar energy, our analysis finds some patterns (differences) involving these meteorological stations with a high intensity of annual solar radiation.

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