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

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.

2019 ◽  
Vol 276 ◽  
pp. 05007
Author(s):  
Soewignjo Agus Nugroho ◽  
Muhamad Yusa ◽  
Andarsin Ongko

As a part of natural geography systems, rock slopes have treasured amount of natural resources potential. The rock materials could be utilized to fulfill several needs, especially to construct buildings. However, society sometimes have taken advantages from the slope’s existence in wrong ways. The exploitations toward rock materials, either through manual or modern way (blasting) have caused some cracks occurred. These cracks have reduced the stability of rock slopes and easily triggered failures on rock slopes. In this paper, the stability of a rock slope will be precisely discussed by using Geological Strength Index (GSI) and was analyzed by using finite element method. The rock samples were taken from Pangkalan (West Sumatera, Indonesia), which this location is also vulnerable to rock slope failures. Geological Strength Index was obtained by doing manual observations on rock sample’s properties, i.e. joint, cracks, and discontinuity. The result was consisted of rock’s properties. Meanwhile, the analysis by using finite element method produced an outcome in form of safety factor. This result could be made as a reference for pre-disaster mitigation in Pangkalan.


Author(s):  
Guangqi Chen ◽  
Lu Zheng ◽  
Yingbin Zhang ◽  
Simeng Dong ◽  
Yasuo Kasugai ◽  
...  

In order to explain the mechanism of breakwater failure destroyed by the massive tsunami triggered by the 2011 off the Pacific coast of Tohoku Earthquake, a failure mode is presented from the view of geotechnical engineering by considering the seepage force rather than the failure modes by using the existing failure mechanisms released in Coastal Engineering. It is proposed that a pseudo-steady state flow condition inside of the rubble mound can be created by high hydraulic head difference, which becomes possible due to the behaviour of the long period of tsunami wave. At first, a piping initiated local failure model is proposed and the phenomenon of piping initiated failure by laboratory model experiments is re-enacted. Also, the piping-initiated local failure of a breakwater is re-enacted by DDA simulation. And then, DDA is applied to the stability analysis of breakwater under seepage flow with new proposed displacement based failure criteria which can consider both global and local failure. A relationship between the height of a tsunami with the safety factor of a breakwater has been obtained. The results have been validated by both the laboratory model experiments and comparison with simplified Bishop Method.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad Hossein Taherynia ◽  
Mojtaba Mohammadi ◽  
Rasoul Ajalloeian

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.


2020 ◽  
Vol 14 (6) ◽  
pp. 1849-1855
Author(s):  
Philipp Mamot ◽  
Samuel Weber ◽  
Maximilian Lanz ◽  
Michael Krautblatter

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.


2021 ◽  
Author(s):  
Niccolò Menegoni ◽  
Daniele Giordan ◽  
Cesare Perotti

<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>


2013 ◽  
Vol 353-356 ◽  
pp. 2531-2536
Author(s):  
Xiu Guang Song ◽  
Zhi Dong Zhou ◽  
Hong Bo Zhang ◽  
Hong Ya Yue

In order to solve the problem of differential settlement, seepage flow and stability between the new and old dam boundary in capacity increasing of the plain reservoirs, the comparative analysis on the stability of the dam slope with different methods on dealing with the new and old dam boundary was performed by numerical simulation with FLAC3D. The result shows that combining the new and old dam by using geogrid indicates superiority for reducing differential settlement, improving the dam stability and safety, etc. In the meantime, on the basis of actual site investigation and theoretical analysis, combined with the requirements of design, construction and management in capacity increasing of the plain reservoirs, the key construction technology was put forward and widely applied foreground, which can improve the quality of the construction, reduce engineering disease and provide references for capacity increasing engineering of in plain reservoirs.


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