scholarly journals Probabilistic approach to the stability of rock slopes

1993 ◽  
Vol 30 (3) ◽  
pp. A192
Keyword(s):  
Probabilistic Approach ◽  
Rock Slopes ◽  
The Stability

scholarly journals The performance of ultra-lightweight foamed concrete incorporating nanosilica

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Pawel Sikora ◽  
Sang-Yeop Chung ◽  
Dietmar Stephan
Keyword(s):  
Wall Thickness ◽  
Probabilistic Approach ◽  
Drying Shrinkage ◽  
Dry Density ◽  
Optimal Dosage ◽  
X Ray ◽  
Mechanical And Physical Properties ◽  
Fresh State ◽  
Foamed Concrete ◽  
The Stability

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.

scholarly journals Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad Hossein Taherynia ◽  
Mojtaba Mohammadi ◽  
Rasoul Ajalloeian
Keyword(s):  
Rock Mass ◽  
Risk Analysis ◽  
Rock Slope ◽  
Classification Systems ◽  
Slope Instability ◽  
Rock Slope Stability ◽  
Rock Slopes ◽  
The Stability ◽  
Cut Slopes ◽  
Road Cut Slopes

Assessment of the stability of natural and artificial rock slopes is an important topic in the rock mechanics sciences. One of the most widely used methods for this purpose is the classification of the slope rock mass. In the recent decades, several rock slope classification systems are presented by many researchers. Each one of these rock mass classification systems uses different parameters and rating systems. These differences are due to the diversity of affecting parameters and the degree of influence on the rock slope stability. Another important point in rock slope stability is appraisal hazard and risk analysis. In the risk analysis, the degree of danger of rock slope instability is determined. The Lashotor pass is located in the Shiraz-Isfahan highway in Iran. Field surveys indicate that there are high potentialities of instability in the road cut slopes of the Lashotor pass. In the current paper, the stability of the rock slopes in the Lashotor pass is studied comprehensively with different classification methods. For risk analyses, we estimated dangerous area by use of the RocFall software. Furthermore, the dangers of falling rocks for the vehicles passing the Lashotor pass are estimated according to rockfall hazard rating system.

scholarly journals Brief communication: The influence of mica-rich rocks on the shear strength of ice-filled discontinuities

2020 ◽  
Vol 14 (6) ◽  
pp. 1849-1855
Author(s):  
Philipp Mamot ◽  
Samuel Weber ◽  
Maximilian Lanz ◽  
Michael Krautblatter
Keyword(s):  
Shear Strength ◽  
Failure Criterion ◽  
Rock Slopes ◽  
Surface Charges ◽  
Permafrost Rock ◽  
Rock Types ◽  
Negative Surface ◽  
The Stability ◽  
Stress Dependent ◽  
Dependent Failure

Abstract. A temperature- and stress-dependent failure criterion for ice-filled rock (limestone) joints was proposed in 2018 as an essential tool to assess and model the stability of degrading permafrost rock slopes. To test the applicability to other rock types, we conducted laboratory tests with mica schist and gneiss, which provide the maximum expected deviation of lithological effects on the shear strength due to strong negative surface charges affecting the rock–ice interface. Retesting 120 samples at temperatures from −10 to −0.5 ∘C and normal stress of 100 to 400 kPa, we show that even for controversial rocks the failure criterion stays unaltered, suggesting that the failure criterion is transferable to mostly all rock types.

An algorithm for the 3D ROck Slope Kinematic Analysis (ROKA) based on RPAS digital photogrammetry data.

2021 ◽  
Author(s):  
Niccolò Menegoni ◽  
Daniele Giordan ◽  
Cesare Perotti
Keyword(s):  
Kinematic Analysis ◽  
Rock Slope ◽  
Traditional Approach ◽  
Rock Slopes ◽  
Digital Photogrammetry ◽  
Modes Of Failure ◽  
Wedge Sliding ◽  
Flexural Toppling ◽  
The Stability ◽  
Digital Outcrop

<p>Among the several adopted methods for the kinematic analysis of the possible modes of failure that could affect a rock slope, the Markland test is the most used. Whereas, it has the advantage of being simple and fast, it has some limits, as the impossibility to manually consider the several different slope orientations and their interaction with the discontinuity dimensions and positions.</p><p>Recently, the improvements in the Remote Piloted Aerial System (RPAS) digital photogrammetry techniques for the development and mapping of Digital Outcrop Models (DOMs) have given the possibility of developing new automatized digital approaches. In this study, ROKA (ROck slope Kinematic Analysis) algorithm is presented. It is an open-source algorithm, written in MATLAB language, which aims to perform the kinematic analysis of the stability of a rock slope using the discontinuity measurements collected onto 3D DOMs. Its main advantage is the possibility to identify the possible critical combination between the 3D georeferenced discontinuities and the local surface of the slope. In particular, the critical combinations that can activate the planar sliding, flexural toppling, wedge sliding and direct toppling modes of failures can be detected and highlighted directly on the DOM. Hence, the ROKA algorithm can make the traditional approach for the kinematic analysis of a rock slope more effective, allowing not only to simplify the analysis, but also to increase its detail. This can be very important, in particular, for the analysis of large and complex rock slopes.</p>

Analysis and Stability Enhancement of DG Sourced Power System with Modified AVR and PSS

2013 ◽  
Vol 768 ◽  
pp. 313-316
Author(s):  
P. Sivakumar ◽  
C. Birindha
Keyword(s):  
Power System ◽  
Distribution System ◽  
Transient Stability ◽  
Probabilistic Approach ◽  
Small Signal Stability ◽  
Signal Stability ◽  
The Stability ◽  
System Stabilizer ◽  
Stability Issues ◽  
Stability Enhancement

Distribution system is facing stability issues with integration of distributed generators and controllers. This proposed method presents the stability of renewable energy based distribution system with varying energy source considering intermittent nature of wind and solar energy using probabilistic approach. The system is supplied by conventional and distributed generating sources like PV and wind. Monte Carlo approach is used for predicting the wind and solar power uncertainties. Proposed work explains both small signal stability and transient stability enhancement of DG sourced power system with power system stabilizer and automatic voltage regulator .It is carried out in is 4 machine 10 bus system. The initial simulation has been carried out using MATLAB/SIMULINK.

Stability of highly fractured infinite rock slopes with nonlinear failure criteria and nonassociated flow laws

2005 ◽  
Vol 42 (2) ◽  
pp. 393-411 ◽  
Author(s):  
Alcibíades Serrano ◽  
Claudio Olalla ◽  
Jesús Manzanas
Keyword(s):  
Quantitative Estimation ◽  
Seepage Flow ◽  
Specific Weight ◽  
Failure Criteria ◽  
Geological Strength Index ◽  
Rock Slopes ◽  
Linear Type ◽  
Isotropic Rock ◽  
The Stability ◽  
Flow Laws

The effect of the dilatancy phenomenon on rock masses is not usually considered when calculating slope stability. A theoretical analysis has been conducted on the stability of infinite rock slopes, with varied hypotheses of simplified seepage flow nets. The calculations were made in the most general way possible, for any type of failure criterion and for linear-type flow laws. When the calculations were completed they were applied to the original and modified Hoek–Brown failure criteria and also to the associated flow and constant-dilatancy conditions. The study reveals the great importance of the dilatancy value and the "non-conservative" nature of an associated flow law hypothesis, which is the hypothesis that is generally used. The important effect of groundwater flow in the slope has also been enhanced. A quantitative estimation of the stability is provided for homogeneous and isotropic rock media under different angles of dilatancy and water flow nets. Lastly, the equilibrium is dependent on the following parameters: slope inclination angle (α), specific weight of the rock mass (γR*), type of rock (m0), unconfined compression strength (σc*), and geological strength index (GSI).Key words: infinite rock slope, Hoek Brown, dilatancy.

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