Limits to common toppling

1989 ◽  
Vol 26 (4) ◽  
pp. 737-742 ◽  
Author(s):  
D. M. Cruden

Goodman and Bray's kinematic model of common toppling can be extended to show that the maximum angle between the slope and the dip direction of the penetrative discontinuity that allows toppling depends on the friction angle of the discontinuities and the angle of the slope when the discontinuities dip into the slope. Flexural toppling can occur when the discontinuities dip in the same direction as the slope but more steeply than the slope and the angle of friction on the discontinuities. Natural examples of toppling in these extended ranges of orientations occur. Key words: toppling, discontinuity, rock slope, anaclinal, cataclinal, plagoclinal, orthoclinal, underdip.

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>


1985 ◽  
Vol 22 (3) ◽  
pp. 277-285 ◽  
Author(s):  
R. T. Yoshida ◽  
J. Krahn

This paper presents a case history of a multiblock landslide where the blocks move at varying rates along a common horizontal slip surface which follows the contact between stratified drift and underlying till. Movement measurements indicate that the blocks towards the toe move at a higher rate than blocks towards the scarp. Stability analyses show that the entire slide mass can be analyzed as a single unit as opposed to considering each block separately. This finding is compared with the analysis of other multiblock slides. The friction angle mobilized along the horizontal slip surface falls within the range of residual values measured in the laboratory. Key words: landslides, stability, analysis, translational slides, residual strength.


2012 ◽  
Vol 446-449 ◽  
pp. 2470-2473 ◽  
Author(s):  
Rui Gao ◽  
Ling Qiang Yang

Using the measured experimental field data of two faults of a rock slope engineering, based on the large number of measured data analysis results of similar projects and rock style to determine the internal friction angle of the fault.the method of how to choose the good date was given. Back analysis method and number fitting method was used to determine the cohesion of fault; anti-slide pile is the lateral force column, the relation of the four failure modes of anti-slide pile was considered. The statistical parameters of resistance of anti-slide pile was calculated by structure mechnics. The norm recommended coefficient transmission method was used to determine function of random variables of slope sliding. The results show that using back analysis method and structure mechnics method to modify the parameter can decrease the uncertainty and improve the reliability of engineering design .


2013 ◽  
Vol 405-408 ◽  
pp. 527-534
Author(s):  
Qi Wu ◽  
Xu Biao Deng

The paper set an example of high antidip sandwich rock slope to study its creep and fracturing deformation in high in-situ stresses at Jinping First Stage Hydropower Station in China. The slope creep deformation before and after excavation could be found on slope face and in exploration adits. Displacements at 4 monitoring points on the slope were abnormal for influences of fault f42-9, zone SL44-1 and lamprophyre dike, which indicate creep and fracturing of the big block separated by them. Through stereographic projection analysis, intersection of controlling structural planes of the big block direct outside the slope. Its bottom slide face, fault f42-9, has internal friction angle smaller than depression angle of the intersection line. Barricade in front of the big block removed by slope excavation decreased resistance to slope slide. It is concluded that creep and fracturing deformation of the big block is controlling stability of the slope.


2021 ◽  
Vol 304 ◽  
pp. 03035
Author(s):  
Sanovar Khamrayeva ◽  
Dilfuza Kadirova ◽  
Sayidvoris Rakhimkhodjayev

Specialists in the weaving industry are often interested in the question of what tension of the warp and weft threads must be set on the weaving machine to produce a particular fabric. Along with this, they are interested in the question of what is the relationship between these parameters and the structure of the fabric, how much it is necessary to increase or decrease the tension of the warp and weft threads when changing the assortment of fabric. These problems arise because the correct thread tension on weaving machines increases the productivity of equipment and labor, and also improves the quality of the fabrics produced. The current state of the mechanics of a weighty deformable flexible thread on a plane and other forms of guides do not take into account the rigidity of the threads on the friction surface, since this parameter is determined by the type and type of threads, the linear density of the threads and the elastic properties of the threads. Therefore, the article analyzes the work on the mechanics of textile yarn and studies of the tension of the yarns were carried out depending on the radius of friction, angle of friction, coefficient of friction and stiffness of the yarns.


2020 ◽  
Vol 1 (1) ◽  
pp. 453-462
Author(s):  
Mutiara Andini ◽  
Niki Rahma Rizkita ◽  
Pherto Rimos ◽  
Febri E. Prihasto ◽  
Ahmad R. Trilaksana ◽  
...  

ABSTRAK Untuk mendukung kegiatan operasional penambangan, perlu dilakukan pembuatan kajian geoteknik yang bertujuan sebagai rencana awal desain lereng tambang maupun mengevaluasi kestabilan lereng pada saat kegiatan penambangan berlangsung. Untuk pembuatan kajian geoteknik di Site Pomalaa, dilakukan pengambilan 15 sampel untuk masing-masing domain (Hazburgit, Dunit, Serpentinit dan Peridotit) yang dibagi menjadi 5 sampel limonit, 5 sample saprolit dan 5 sampel bedrock. Selanjutnya, sampel tersebut dilakukan pengujian di laboratorium untuk mendapatakan nilai material properties. Material propertis limonit pada setiap domain  memiliki rentang nilai kohesi 31,22 kN/m2- 40,49 kN/m2, sudut geser dalam 31,30o-37,36o, berat jenis basah 11,56 kN/m2-12,89 kN/m2, UCS 0,11Mpa – 0,59 Mpa.Sedangkan nilai material propertis pada saprolit memiliki rentang nilai kohesi 31,22 kN/m2-39,18 kN/m2, sudut geser dalam 34,71o-39,11o, berat jenis basah 10,86 kN/m2-13,52 kN/m2, UCS 0,19Mpa – 0,29 MPa. Material propertis tersebut selanjutnya digunakan sebagai parameter dalam melakukan analisis kestabilan lereng dengan mengeluarkan nilai faktor keamanan (FK) dan probability of failure (PoF). Pada kajian ini dilakukan simulasi dengan 4 pendekatan : (a) Pertama, menganalisis lereng dengan domain geologi tunggal, (b)Kedua, menganalisis lereng dengan menggabungkan 2 domain geologi yang berbeda, (c) Ketiga, menganalisis lereng dengan menggabungkan 3 domain geologi yang berbeda, (d) Menganalisis lereng dengan menggabungkan 4 domain geologi yang berbeda. Hasil simulasi dengan menggunakan 4 pendekatan tersebut menunjukkan nilai rata-rata FK limonit secara berturut sebesar 1.72, 1.71,1.73, dan 1.73 . Sedangkan nilai FK saprolit secara berturut sebesar 1.74, 1.78 , 1.75 dan  1.74. Rata-rata probability of failure pada simulasi ini dibawah 1%. Dari hasil simulasi dapat dilihat bahwa nilai faktor keamanan dari hasil simulasi beberapa material menunjukkan nilai yang konsisten, sehingga dapat dikatakan bahwa nilai material propertis nikel laterit pada batuan dasar yang berbeda cenderung sama (homogen), oleh karena itu pengambilan sampel geoteknik di site pomalaa tidak sensitif terhadap domain batuan. Key words: Domain Batuan Dasar, Kohesi, Sudut Geser Dalam, Berat Jenis Basah, UCS, Faktor Keamanan, Probability of Failure.  ABSTRACT Concerning mining operations activities, geotechnical analysis should be carried out with the aim of planning the initial design of slope and evaluating the stability of the slope during mining activities. For making geotechnical studies at the Pomalaa Site, 15 samples were taken for each domain (Hazburgit, Dunit, Serpentinit and Peridotit) which were allocated into 5 samples for limonite, 5 samples for saprolite and 5 samples for bedrock. Furthermore, the sample is tested in a laboratory to obtain the value of material properties. Limonite property material in each domain has a range of cohesion values of 31.22 kN / m2-40.49 kN / m2, friction angle at 31.30o-37.36o, wet density 11.56 kN / m2-12.89 kN / m2, UCS 0.11Mpa - 0.59 Mpa. While the value of proper material in saprolite has a range of cohesion values of 31.22 kN / m2-39.18 kN / m2, shear angle in 34.71o-39.11o, wet specific gravity 10.86 kN / m2-13.52 kN / m2, UCS 0.19Mpa - 0.29 Mpa. The property material is then used as a parameter input to obtain slope stability analysis by issuing factor of safety (FK) and probability of failure (PoF) values ). In this case a simulation was conducted to 4 approaches: (a) First, analyzing slopes with a single geological domain, (b) Second, analyzing slopes by combining 2 different geological domains, (c) Third, analyzing slopes by combining 3 different geological domains , (d) Analyze slopes by combining 4 different geological domains. The simulation results using the 4 approaches show the average value of FK limonite which are 1.72, 1.71.1.73, and 1.73 respectively. While FK saprolite values were 1.74, 1.78, 1.75 and 1.74 respectively. The average probability of failure in this simulation is below 1%. From the simulation results it can be seen that the value of the safety factor from the simulation results of several materials shows a consistent value, so it can be said that the material value of laterite nickel properties in different bedrock tends to be the same (homogeneous), therefore geotechnical sampling at the Pomalaa site is not sensitive to the rock domain. Key words: Host Rock Domain, Cohesion, Friction angle, Wet Specific Gravity, UCS, Safety Factor, Probability of Failure.


1970 ◽  
Vol 4 (1) ◽  
pp. 149-154
Author(s):  
Md. Tohidul Islam ◽  
Md. Serazul Islam ◽  
Md Nurul Hoque

This paper elucidated an attempt to determine the physical properties of some selected soils at different location under Mymensingh districts. The properties of soils were determined using standard methods. Field moisture content was more or less similar for all the locations. The dry unit weights of selected seven soils for Bangladesh Institute of Nuclear Agriculture (BINA), Valuka, Muktagacha, Trisal, Madhupur, Chorkhai and Shomvoganj sites were found to be 17.61, 16.50, 17.00, 17.50, 15.50, 16.40 and 16.20 kN/m3, respectively while the specific gravities were found as 2.67, 2.66, 2.68, 2.70, 2.69, 2.72 and 2.65, respectively also the values of plastic limits of soils were found to be 16.00, 17.00, 15.50, 18.50, 16.00, 17.20 and 14.00 percent, respectively whereas the plasticity index values were 16.25, 14.50, 15.00, 17.00, 18.00, 13.60 and 15.50 percent, respectively for the above locations. The liquid and plastic limits varied for all the locations but the plasticity index values were found more or less similar for all the soil samples. The friction angles were found more or less similar while cohesion varied for different locations. The properties of soils thus obtained can be used for soils of these areas of Bangladesh. A relation between the gradations with plasticity indices of different soils was also characterized. Key words: Dry unit weights, plastic limits, plasticity index, shear stress and internal friction angle.


2013 ◽  
Vol 690-693 ◽  
pp. 756-759 ◽  
Author(s):  
Zhao Rong Jiang ◽  
Le Hua Wang

The orthogonal design can make sites in the test range uniformly distributed, which is introduced to slope sensitivity analysis, and can greatly reduce the test times and gets a good test effect.The paper takes the flood discharging tunnel import slope of Jinchuan hydropower station for example, which is a rock slope. This article selects the bulk density, internal friction angle, cohesion, earthquake acceleration four factors to design the orthogonal experiment, and the safety factor of the slope as a test indicators, using the simplified Bishop method of limit equilibrium theory to calculate the safety factor and analyses the slope sensitivity. The results show that the cohesion and earthquake acceleration are the most sensitive factors, and have a very significant impact on the slope stability.


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