scholarly journals Study of the Stability of a Soil-Rock Road Cutting Slope in a Permafrost Region of Hulunbuir

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yuxia Zhao ◽  
Jun Feng ◽  
Kangqi Liu ◽  
Hongwei Xu ◽  
Liqun Wang ◽  
...  
Keyword(s):  
High Latitude ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
In Situ Monitoring ◽  
Permafrost Region ◽  
Freeze Thaw ◽  
Stability Of Slopes ◽  
Low Altitude ◽  
The Stability ◽  
Permafrost Regions

Due to the threat of global warming and the accelerated melting of glaciers and permafrost, the stability of slopes in permafrost regions has received an increasing amount of attention from scholars. However, research on the stability of soil-rock road cutting slopes in high-latitude and low-altitude permafrost regions of the Greater Khingan Mountains in the Inner Mongolia Autonomous Region has not been reported. For this reason, a study of the stability of a slope with a high ice content in section K105 + 600 to K105 + 700 of National Highway 332 is conducted. The slope is 20 m high and the slope angle is 45°, and the risk of landslides on this slope under the action of freeze-thaw erosion is very high. Because of this, field in situ monitoring, indoor freeze-thaw tests, thermal parameter tests, and ABAQUS numerical simulation models are used to study the stability of the slope. After collecting the continuous temperature, moisture, settlement, and slope deformation data, it was found that the slope was undergoing dynamic changes. The creep of shallow slopes increased with the number of freeze-thaw cycles. After approximately 150 freeze-thaw cycles, the slope safety factor was less than 1, which means that the slope had reached the limit equilibrium state. Therefore, freeze-thaw erosion greatly reduced the stability of the slope. Hence, the stability of the slope must be protected during its entire life cycle. This study provides a reference for the design and construction of road cutting slopes in the high-latitude and low-altitude permafrost regions of the Greater Khingan Mountains.

scholarly journals Effect of Freeze-Thaw on the Stability of a Cutting Slope in a High-Latitude and Low-Altitude Permafrost Region

2020 ◽  
Vol 3 (3) ◽  
pp. 36
Author(s):  
Yuxia Zhao ◽  
Liqun Wang ◽  
Han Li
Keyword(s):  
Compressive Strength ◽  
Safety Factor ◽  
High Latitude ◽  
Permafrost Region ◽  
Freeze Thaw ◽  
Slowing Down ◽  
Cutting Slope ◽  
Low Altitude ◽  
The Stability ◽  
Permafrost Regions

In order to study the influence of freeze-thaw cycles on the stability of cutting slopes in high-latitude and low-altitude permafrost regions, we selected a cutting slope (the K105+700–800 section of National Highway 332) in the Elunchun Autonomous Banner in Inner Mongolia as the research object. Located in the Greater Xing’an Mountains, the permafrost in the Elunchun Autonomous Banner is a high-latitude and low-altitude permafrost. The area is also dominated by island-shaped permafrost, which increases the difficulty of dealing with cutting slopes, due to its morphological complexity. Surface collapse, caused by freeze-thaw erosion in this area, is the main reason for the instability of the cutting slope. Indoor freeze-thaw tests, field monitoring, and an ABAQUS numerical simulation model were conducted so as to quantify the decrease in rock strength and slope stability under freeze-thaw conditions. The following conclusions were drawn. (1) As the number of freeze-thaw cycles increased, the compressive strength of the rock specimens obtained from this slope gradually decreased. After 50 freeze-thaw cycles, the uniaxial compressive strength measured by the test decreased from 40 MPa to 12 MPa, a decrease of 37%. The elastic modulus value was reduced by 47%. (2) The safety factor of the slope—calculated by the strength reduction method under the dynamic analysis of coupled heat, moisture, and stress—gradually decreased. After 50 freeze-thaw cycles, the safety factor of the slope was only 0.74. (3) Reasonably reducing the number of freeze-thaw cycles, reducing the water content of the slope, slowing down the slope, and increasing the number of grading steps can effectively improve the stability of the slope. The results of this study can provide a reference for the design and stability analysis of slopes in permafrost regions of the Greater Xing’an Mountains.

scholarly journals Optimal profile for concave slopes under static and seismic conditions

2016 ◽  
Vol 53 (9) ◽  
pp. 1522-1532 ◽  
Author(s):  
Farshid Vahedifard ◽  
Shahriar Shahrokhabadi ◽  
Dov Leshchinsky
Keyword(s):  
Limit Equilibrium ◽  
Stable Configuration ◽  
Preliminary Evaluation ◽  
Construction Technology ◽  
Stability Of Slopes ◽  
Optimal Profile ◽  
Stabilized Soil ◽  
The Stability ◽  
Comparison Of The Results ◽  
The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

Stability of Earth Masses and Slopes

2015 ◽  
pp. 528-588
Keyword(s):  
Cross Sections ◽  
Limit Equilibrium ◽  
Circle Method ◽  
Earth Dam ◽  
Stability Of Slopes ◽  
Solution Of Equations ◽  
Analysis Of Stability ◽  
The Stability ◽  
Cut Slopes ◽  
Type Of Failure

The design of open-cut slopes and embankments, foundations, levees, and earth-dam cross-sections is based primarily on stability considerations. There are many causes and types of earth instability. There are also many ways of analyzing the stability of slopes. The chapter considers the limit equilibrium approach, which aims essentially to determine a factor of safety, F, that would ensure a slope does not fail. The chapter considers the analysis of stability of infinite slopes based on translational type of failure and the analysis of finite slopes using the Swedish Method, Method of Slices, Bishop Simplified Method, Friction Circle Method, and the Translational Method. The solution of equations developed for the analysis of stability of slopes can be tedious and time consuming. A way of reducing the amount of calculation required in slope stability studies is by use of charts based on geometric similarity. The chapter discusses how Taylor (1948) and Janbu (1964) charts are used in stability analysis of slopes. Finally, the chapter discusses ways to reduce the risk of instability in slopes.

scholarly journals Simulating high-latitude permafrost regions by the JSBACH terrestrial ecosystem model

2014 ◽  
Vol 7 (2) ◽  
pp. 631-647 ◽  
Author(s):  
A. Ekici ◽  
C. Beer ◽  
S. Hagemann ◽  
J. Boike ◽  
M. Langer ◽  
...  
Keyword(s):  
High Latitude ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Layered Soil ◽  
Data Sets ◽  
High Latitudes ◽  
Current Version ◽  
Freeze Thaw ◽  
Terrestrial Ecosystem Model ◽  
Permafrost Regions

Abstract. The current version of JSBACH incorporates phenomena specific to high latitudes: freeze/thaw processes, coupling thermal and hydrological processes in a layered soil scheme, defining a multilayer snow representation and an insulating moss cover. Evaluations using comprehensive Arctic data sets show comparable results at the site, basin, continental and circumarctic scales. Such comparisons highlight the need to include processes relevant to high-latitude systems in order to capture the dynamics, and therefore realistically predict the evolution of this climatically critical biome.

scholarly journals Deterministic and Probabilistic Analysis of Dasdhunga Soil Slope along Narayangarh-Mugling Road Section

2021 ◽  
Vol 6 ◽  
pp. 187-198
Author(s):  
Saurav Shrestha ◽  
Indra Prasad Acharya ◽  
Ranjan Kumar Dahal
Keyword(s):  
Limit Equilibrium ◽  
Water Pressure ◽  
Slope Angle ◽  
Friction Angle ◽  
Probability Of Failure ◽  
Soil Slope ◽  
Extrinsic Factors ◽  
Stability Of Slopes ◽  
Road Section ◽  
Truncated Normal

Instability of slopes is usually governed by a combination of intrinsic and extrinsic factors. The inherent variability of parameters make the problem probabilistic rather than a deterministic one. This research deals with evaluation of stability of slopes with the calculation of the factor of safety of Dasdhunga soil slope along Narayangarh- Mugling road section under different rainfall conditions through the use of coupled finite element and limit equilibrium method in GeoStudio and the determination of probability of failure by sliding, modeled as infinite slopes by using Monte Carlo simulation in R-Studio. Mean, standard deviation, minimum and maximum values of the parameters like- friction angle, cohesion and unit weight were computed from eight samples of the slope. The pore water pressure developed and its corresponding statistical data for different rainfall conditions were computed from FEM based SEEP/W simulation. The above parameters are assumed to follow truncated normal probability distribution function and the geometric parameters like height and slope angle are regarded as constant parameters. It was observed that the safety factors for theslopeis low in high intensity-low duration rainfalls and the probability of failure is high. The tendency to fail increases as the return period of rainfall increases and viceversa. Sensitivity analysis performed in both deterministic and probabilistic methods showed that friction angle is the most sensitive.

Rock slope stability and distributed joint systems

1992 ◽  
Vol 29 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Bruce J. Carter ◽  
Emery Z. Lajtai
Keyword(s):  
Factor Of Safety ◽  
Rock Slope ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Probability Of Failure ◽  
Cumulative Distribution ◽  
Rock Slope Stability ◽  
Sensitivity Analyses ◽  
The Stability ◽  
Rock Wedge

A deterministic (GEOSLIDE) and a probabilistic (PROSLIDE) microcomputer code are introduced to aid in performing rock wedge analyses based on the limit equilibrium method. The deterministic code evaluates the stability of a single rock wedge formed by discontinuities in rock through three-dimensional vector algebra, GEOSLIDE undertakes a full kinematic analysis (daylighting and obstruction), analyzes both wedge and plane sliding, and provides for anchor designs and sensitivity analyses (cohesion, friction, and water forces). Through multiple stability analyses, PROSLIDE evaluates the probability of failure for a rock slope by examining the distribution of the factors of safety from all the potential sliding wedges formed by the discontinuities of the rock mass. The probability of failure is expressed as the ratio of kinematically free wedges that have a factor of safety less than unity to the total number of wedges, PROSLIDE can form and analyze as many as 2000 different pairs of discontinuities in less than 30 min using a 25 MHz 486 IBM-compatible computer. In a worked example, the probability of failure for a fixed slope strike and loading condition is shown to vary with the slope angle, following the characteristic 'S' shape of a cumulative distribution function. The effect of an anchor force is to spread the distribution over a wider range of the factor of safety (SF), pushing many wedges into a potential upslide situation and splitting the distribution about the failure zone of the stability diagram (−1 < SF < 1). Key words : rock slope, rock wedge, stability analysis, factor of safety, probability of failure, Monte Carlo simulation.

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