A Slope Failure in Swelling Clay

1973 ◽  
Vol 10 (3) ◽  
pp. 531-536 ◽  
Author(s):  
G. Kassiff ◽  
I. Alpan
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Climatic Conditions ◽  
Expansive Clay ◽  
Bridge Abutment ◽  
Actual Field ◽  
The Stability ◽  
Short Time ◽  
Loss Of Strength

A recent heavy rainy season in the semiarid climatic conditions of northern and central Israel caused a number of slope failures of embankments and bridge abutments in expansive clay soils.Failure of a 9 m high slope of a bridge abutment is reported. The failure occurred owing to migration of moisture into the clay a short time after the slope was completed. Soil characteristics such as plasticity, swelling potential, and shear strength are presented and discussed. The stability of the slope was analyzed using Taylor's chart and strength parameters obtained from laboratory tests. It is concluded that failure occurred owing to substantial loss of strength following swelling of the clay. Results of laboratory tests for shear strength after saturation and swelling seem to correlate well with actual field conditions in this case.

Interpretation of the limits in shear strength in binary granular mixtures

2001 ◽  
Vol 38 (5) ◽  
pp. 1097-1104 ◽  
Author(s):  
Luis E Vallejo
Keyword(s):  
Shear Strength ◽  
Laboratory Tests ◽  
Relative Concentration ◽  
Frictional Resistance ◽  
Glass Beads ◽  
Rock Fragments ◽  
Structural Support ◽  
Granular Mixtures ◽  
The Stability ◽  
Natural Slopes

Many natural slopes and rockfill structures are made of a mixture of rock fragments and sand-size particles. To analyze the stability of such natural slopes and rockfills, a knowledge of how rock–sand mixtures develop their shear strength is needed. Laboratory tests conducted on mixtures of glass beads of two different sizes (5 and 0.4 mm) have indicated that their shear strength depends upon the relative concentration by weight of the large and small beads in the mixtures. If the concentration by weight of the large beads is greater than 70%, the shear strength of the mixtures is controlled by the frictional resistance of the large beads. If the concentration of the large beads is less than 40%, the shear strength of the mixtures is controlled by the frictional resistance of the small beads. If the concentration of the large beads is between 40 and 70%, the shear strength of the mixture is partially controlled by the frictional resistance provided by the large beads in the mixtures. These limits are very similar to those reported for rock–sand mixtures. To date, no explanation has been put forward to account for why these limits exist. This study presents an explanation for their existence. The explanation is based on the porosity developed by the mixtures and the type of structural support provided by the coarse and fine grains.Key words: shear strength, granular mixtures, porosity, fabric, compaction.

scholarly journals Analisis Pengaruh Fluktuasi Muka Air Waduk terhadap Stabilitas Lereng Waduk Dengan Menggunakan Program Plaxis 2D

2019 ◽  
Vol 24 (2) ◽  
pp. 113
Author(s):  
Paravita Sri Wulandari ◽  
Daniel Tjandra
Keyword(s):  
Shear Strength ◽  
Water Content ◽  
Water Level ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Soil Characteristics ◽  
Soil Samples ◽  
Initial Condition ◽  
Soil Shear Strength ◽  
Influence Of Water

Reservoir is needed as a source of water supply to the surrounding populations. The design of a reservoir needs to consider several aspects of soil embankment such as variations in water content and changes in shear soil shear strength and also the influence of water level in reservoir. The purpose of this research is to analyze these three aspects in the design of a reservoir. This research was begun by taking soil samples for embankment and conducting soil tests to obtain soil characteristics at the initial condition. The further laboratory tests were conducted to determine the effect of changes in water content on the shear strength of the soil. The variation of soil embankment characteristic was then modeled by Plaxis 2D program to obtain the effect of changes in soil embankment characteristic and fluctuation of the water level in the reservoir. The results showed that the increase in water content significantly decrease the shear strength of the soil. The changes of soil shear strength affect the pattern of slope failure and safety factor. In addition, the pattern and direction of the slope failure were also influenced by the water level of the reservoir.

scholarly journals Parametric evaluation of shear strength parameters on the stability of cut slope: a case study from Mahabaleshwar road section, India

2016 ◽  
Vol 51 ◽  
pp. 73-76
Author(s):  
Suman Panthee
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Factor Of Safety ◽  
Slope Failure ◽  
Cut Slope ◽  
Stability Of Slopes ◽  
Proportional Relation ◽  
The Stability

Stability of rock cut slopes depends upon the type of material, discontinuity attributes and geometry present in any location. Although, gravity remains the constant important factor in dictating the slope failure but other parameters like shear strength and available shear stress along the slope also decides the stability of the slopes to great extent. The strength of the material comes from the internal bonding between the mineral grains, contact between the particles and the ability of the material to respond to the stress conditions. Variation of these material attributes fluctuate the cohesion and angle of internal friction that constitutes the most important properties in defining the strength of any material. Rock resists shear stress by these two internal mechanisms. Numerical simulation by Finite Element Method technique is attempted for assessing the stability cut slope. An attempt has been made in this study to document the behavior of strength of the material in terms of stability of slopes by parametric study of cohesion and internal friction. This study carried to understand how the factor of safety changes with reference to change in cut slope height, cohesion and internal friction of the discontinuities that attributes the shear strength of discontinuities. The study is based on Finite Element Modeling (FEM). From the study it is found that factor of safety has strongly proportional relation with cohesion and internal friction but shown inversely proportional relation with height of cut slope.

Forensic Analyses and Rehabilitation of a Failed Highway Embankment Slope in Texas

2021 ◽  
pp. 036119812199635
Author(s):  
Burak Boluk ◽  
Anand J. Puppala ◽  
Sayantan Chakraborty ◽  
Puneet Bhaskar
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Slope Failure ◽  
Engineering Properties ◽  
High Plasticity ◽  
Slope Failures ◽  
Lime Treatment ◽  
Embankment Slope ◽  
The Stability ◽  
Highway Embankment

A comprehensive investigation was designed and conducted to identify the potential causes of failure of a highway embankment slope in Texas and evaluate the effectiveness of lime treatment to rehabilitate the failed slope. Highway slopes built with high plasticity clays often experience shallow slope failures after exposure to repeated wet–dry weathering cycles. Lime stabilization generally reduces the swell–shrink potential, enhances the engineering properties of problematic clayey soils, and can potentially prevent surficial slope failures. However, exposure to wet–dry cycles can negate some of the benefits of lime treatment and therefore a study was conducted to address the use of this lime treatment to stabilize embankment slopes. Extensive laboratory tests were conducted to study the effect of weathering cycles on the degradation of hydro-mechanical properties of untreated and lime-treated soils. Rainfall-induced slope stability analyses were performed to investigate the probable causes of slope failure and evaluate the stability of lime-treated surficial slope. The optimum stabilizer dosage and treated layer thickness required for the slope rehabilitation were determined based on laboratory tests and numerical analysis results. The stability analysis results indicate that the degradation of surficial soil’s hydro-mechanical properties and the development of a perched water table during prolonged rainfall possibly caused the slope failure. The post-treatment increase in shear strength properties, reduction in moisture fluctuations recorded by embedded moisture sensors, and the presence of newly installed underlying drains are expected to prevent recurrence of surficial slope failures. Salient results from this study are covered in this paper.

Study on Influence of Unloading of Vacuum on Stability of Embankment Improved by Vacuum Combined with Preloading

2012 ◽  
Vol 178-181 ◽  
pp. 1688-1693
Author(s):  
Ji Fu Liu ◽  
Guan Feng An ◽  
Gang Zheng
Keyword(s):  
Shear Strength ◽  
Theoretical Analysis ◽  
Safety Factor ◽  
Laboratory Tests ◽  
Soft Clay ◽  
Undrained Shear Strength ◽  
Soft Ground ◽  
Analysis Laboratory ◽  
The Stability ◽  
Undrained Shear

In order to study influence of unloading of vacuum on stability of embankment whose soft ground is improved by vacuum combined with preloading, the change of effective stress of soft clay in the improved area is analyzed when vacuum is unloaded and the undrained shear strength of soft clay in the improved area after unloading of vacuum is deduced. Changes of undrained shear strength of soil and stability of embankment owing to unloading of surcharge are also analyzed for comparison. It is shown by theoretical analysis, laboratory tests and a project that the undrained shear strength of soft clay improved by vacuum combined preloading is decreased after unloading of vacuum and the stability of embankment after unloading of vacuum should be taken into account for design. Safety factor of stability of embankment increases after unloading of surcharge since decrease ratio of load of embankment is more than decrease ratio of undrained shear strength of clay.

Slope Stability Analysis under the Condition of Seepage

2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin
Keyword(s):  
Finite Element Method ◽  
Shear Strength ◽  
Slope Stability ◽  
Negative Impact ◽  
Strength Reduction ◽  
Soil Slope ◽  
Failure State ◽  
Calculation Results ◽  
The Stability ◽  
Shear Strength Reduction

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.

scholarly journals Dual 2-Hydroxypropyl-β-Cyclodextrin and 5,10,15,20-Tetrakis (4-Hydroxyphenyl) Porphyrin System as a Novel Chiral-Achiral Selector Complex for Enantioseparation of Aminoalkanol Derivatives with Anticancer Activity in Capillary Electrophoresis

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 993
Author(s):  
Błażej Grodner ◽  
Mariola Napiórkowska
Keyword(s):  
Capillary Electrophoresis ◽  
Anticancer Agents ◽  
Chiral Discrimination ◽  
Combined Effects ◽  
Pilot Studies ◽  
Repeatability And Reproducibility ◽  
The Stability ◽  
Short Time ◽  
High Separation

In this study, a complex consisting of 2-hydroxypropyl-β-cyclodextrin and 5,10,15,20-tetrakis (4-hydroxyphenyl) porphyrin, (named dual chiral-achiral selector complex) was used for the determination of two novel potential anticancer agents of (I) and (II) aminoalkanol derivatives. This work aimed at developing an effective method that can be utilized for the determination of I (S), I (R), and II (S) and II (R) enantiomers of (I) and (II) compounds through the use of a dual chiral-achiral selector complex consisting of hydroxypropyl-β-cyclodextrin and 5,10,15,20-tetrakis (4-hydroxyphenyl) porphyrin system by applying capillary electrophoresis. This combination proved to be beneficial in achieving high separation selectivity due to the combined effects of different modes of chiral discrimination. The enantiomers of (I) and (II) compounds were separated within a very short time of 3.6–7.2 min, in pH 2.5 phosphate buffer containing 2-hydroxypropyl-β-cyclodextrin and 5,10,15,20-tetrakis (4-hydroxyphenyl) porphyrin system at a concentration of 5 and 10 mM, respectively, at 25 °C and +10 kV. The detection wavelength of the detector was set at 200 nm. The LOD for I (S), I (R), II (S), and II (R) was 65.2, 65.6, 65.1, and 65.7 ng/mL, respectively. LOQ for I (S), I (R), II (S), and II (R) was 216.5, 217.8, 217.1, and 218.1 ng/mL, respectively. Recovery was 94.9–99.9%. The repeatability and reproducibility of the method based on the values of the migration time, and the area under the peak was 0.3–2.9% RSD. The stability of the method was determined at 0.1–4.9% RSD. The developed method was used in the pilot studies for determining the enantiomers I (S), I (R), II (S), and II (R) in the blood serum.

scholarly journals Projections of surface air temperature required to sustain permafrost and importance of adaptation to climate change in the Daisetsu Mountains, Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tokuta Yokohata ◽  
Go Iwahana ◽  
Toshio Sone ◽  
Kazuyuki Saito ◽  
Noriko N. Ishizaki ◽  
...  
Keyword(s):  
Climate Model ◽  
Surface Air Temperature ◽  
Climatic Conditions ◽  
Alpine Ecosystems ◽  
Adaptation To Climate Change ◽  
Freezing And Thawing ◽  
Air Temperatures ◽  
Statistical Relationships ◽  
The Stability ◽  
Slope Displacement

AbstractPermafrost is known to occur in high mountainous areas such as the Daisetsu Mountains in Japan, which are located at the southernmost limit of the permafrost distribution in the world. In this study, areas with climatic conditions suitable for sustaining permafrost in the Daisetsu Mountains are projected using bias-corrected and downscaled climate model outputs and statistical relationships between surface air temperatures and permafrost areas. Using freezing and thawing indices, the size of the area in the Daisetsu Mountains where climatic conditions were suitable for permafrost were estimated to be approximately 150 km2 in 2010. Under the RCP8.5 scenario, this area is projected to decrease to about 30 km2 by 2050 and it is projected to disappear by around 2070. Under the RCP2.6 scenario, the area is projected to decrease to approximately 20 km2 by 2100. The degradation of mountain permafrost could potentially affect the stability of trekking trails due to slope displacement, and it may also have deleterious effects on current alpine ecosystems. It is therefore important to accurately monitor changes in the mountain ecosystem environment and to implement measures to adapt to an environment that is projected to change significantly in the future.

Foreign exchange earnings of the countries of the world from international trade in fruit and berry products

2021 ◽  
pp. 45-56
Author(s):  
Rafail R. Mukhametzyanov ◽  
◽  
Nikolay G. Platonovskiy ◽  
Akhmed M. Khezhev ◽  
Tatiyana V. Ostapchuk ◽  
...  
Keyword(s):  
International Trade ◽  
Foreign Exchange ◽  
Import Substitution ◽  
World Order ◽  
Climatic Conditions ◽  
The European Union ◽  
The World ◽  
Increasing Demand ◽  
Processed Products ◽  
The Stability

In the context of the modern global financial world order, an important element of the stability of the national monetary unit of the overwhelming majority of countries in the world, especially developing countries, is foreign exchange earnings. For some countries with favorable natural and climatic conditions, the production, processing and export of agricultural products plays a significant role in the overall structure of foreign exchange earnings in the country. The constantly increasing demand from consumers for fruits, berries, nuts and their processed products allows economic entities of national fruit and berry subcomplexes to increase the volume of growing and exporting these types of products. This study analyzes the change in the volume of exports and imports of fruit and berry products in value terms for the period 2010-2019. It is revealed that some states, being the largest exporters of fruits, berries, nuts and products of their processing, occupy significant positions in the import of these types of products from abroad. Based on the author’s calculations, the top 30 countries of the world have been compiled in terms of net foreign exchange earnings from international trade in this type of product. According to this indicator, the first line with a level of $ 7.506 billion was occupied by Spain, while it increased it by $ 1.675 billion over 10 years. As for Russia, despite the counter-sanctions against the countries of the European Union and some other countries of the world, as well as the ongoing policy of import substitution, including in domestic gardening, it continues to be one of the main importers of fruits, berries, nuts and their processing products in the world. Thus, our country supports both foreign producers and other commercial structures that carry out the processes of commodity circulation of fruit and berry products, and the receipt of foreign exchange earnings in these powers.

PNEUMATIC VIBROISOLATION SYSTEM OF THE BASE DESK WITH NATURAL FREQUENCY REGULATION

2021 ◽  
Vol 113 ◽  
pp. 91-100
Author(s):  
Radka JÍROVÁ ◽  
Lubomír PEŠÍK
Keyword(s):  
Natural Frequency ◽  
Automotive Industry ◽  
Natural Frequencies ◽  
Dynamical Behaviour ◽  
Operating Conditions ◽  
Frequency Regulation ◽  
The Stability ◽  
Short Time

Vibroisolation systems of base desks for machine and testing facilities usually cannot effect efficient changing of their own frequencies according to operating conditions. Especially in the case of the automotive industry, the possibility of changing natural frequencies is very desirable. During varying operating conditions, the vibroisolation system needs to be regulated easily and quickly regarding the minimisation of dynamical forces transmitted to the ground and to ensure the stability of the testing process. This paper describes one of the options of tuning the base desk at a relatively short time and by sufficient change of own frequencies, which decides the dynamical behaviour of the whole system.

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