How do friction and cohesion work together to stabilize slopes. The term landslide refers to a situation of instability affecting natural slopes and involving large volumes of soil. A homogeneous rock slope is to be analyzed for planar failure along a. In this paper a numerical analysis of slope stability problems in blocky rock is presented with emphasis given to the various possible failure modes block sliding andor block tilting. In hard rock, blasting of the slope will likely be required.
Variation of failure mechanisms of slopes in jointed rock masses. Taylors stability number if the slope angle, height of embankment h, the effective unit weight of material, angle of internal friction, and unit cohesion c are known, the factor of safety may be determined. Figure 143 shows a slope cut in a weathered rock in which the degree of weathering varies from residual soil in the upper part of the slope to slightly weathered rock near the toe. The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering and engineering geology. The objective of the analysis was to evaluate and judge the condition and overall stability of. In a probabilistic slope stability analysis the input parameters are considered as. Mar 21, 2016 taylors stability number if the slope angle, height of embankment h, the effective unit weight of material, angle of internal friction, and unit cohesion c are known, the factor of safety may be determined. The stability of this particular slope was critical because it. Low rock cuts rock slopes or soil slopes by the designer. The slope, which has a height of 10 m, is assumed loaded under gravity with a horizontal to vertical stress ratio of 1. We analyzed seismic displacements using simplified spreadsheetbased methods developed by bray and travasarou 2007. Gravity is the force that acts everywhere on the earths surface, pulling everything in a direction toward the center of the earth.
It is shown that by combining field and laboratory measurements and engineering. After a number of years of international collaboration, the lop produced guidelines for open pit slope design, which were formally presented to the mining and geotechnical community at the slope stability 2009 conference in santiago chile, and. Rock slope stability analysis utilization of advanced. Rules of thumb and easy method of estimating slope stability geology and soils information needed from site or soils database check appropriate loading conditions seeps, rapid drawdown, fluctuating water levels, flows select values to input for. Pdf stability analysis of a rock slope in himalayas. These analyses are often completed using slope stability charts and the dsara deterministic stability analysis for road access slope stability program.
Taylor 1937 conceived the idea of analyzing the stability of a large number of slopes through a wide range of slope angles and. The effect of spacing of rock bolts on the stability of rock. They are certainly major factors in cut slope stability and in. An introduction to slope stability and protection j. The term slope means a portion of the natural slope whose original profile has been modified by artificial interventions relevant with respect to stability. On civil projects, rock cuts must be safe from rock falls and largescale slope instability during both construction and operation.
Under fully drained slope condition, the water pressure is zero. Whether youre involved in surface mine design or production, construction, education, or regulation, this is an important new book for your library. The cross sections used for our 2d slope stability analyses are based on cross section cc figure 4. Erosion, driven by gravity, is the inevitable response to that uplift, and various types of erosion, including mass wasting, have created slopes in the uplifted regions. Chapter 10 slope stability analysis nysdot geotechnical page 106 january 21, 2014 design manual 10. On a flat surface the force of gravity acts downward.
The effect of spacing of rock bolts on the stability of. Field reconnaissance and a detailed fracture survey of the rock slopes were conducted by dr. This was applied in the model by selecting all the boundary lines between the mudstone and weathered mudstone unshow the water table, to facilitate. This book focuses on rock slope stability, with sections on geological data collection. Although fembased ssr analysis is an alternative to conventional limit equilibrium methods in many cases, its ability to readily combine slip along joints with. Stability analysis and failure mechanisms of open pit rock slope.
Probabilistic approach for open pit bench slope stability analysis a. We illustrate the merits of the suggested approach on an example of a 10 m homogeneous rock slope with a 35. These seven causes of rock falls together account for 68 percent of the total falls. Application note slope stability analysis worked example. Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement. A slope stability problem in hong kong 7 the symbols and dimensions used in these models are as follows. Chapters include geotechnical and geomechanical analysis techniques. The rocks present at the bridge site are heavily jointed. Many researchers have identified this fundamental control on paraglacial rock slope failure distributions thorarinsson et al.
Pdf a new approach for prediction of the stability of soil and rock. Stability analysis of a rock slope in himalayas 3 fig. The objective of the analysis was to evaluate and judge the condition and overall stability of the exposed rock, and identify where. Methods for analysis of slope stability are described and are illustrated by examples in the appendixes. Pdf purpose analysis of stability of slopes has been the subject of many research works in the past decades. Softer rock slopes may be laid back to match existing soil slopes and covered with topsoil and vegetation. Erik eberhardt university of british columbia geological engineeringearth and ocean sciences, ubc, 6339 stores rd. Paul guyer is a registered mechanical engineer, civil engineer, fire protection engineer and architect with over 35 years experience in the design of buildings and related infrastructure. The stability of rock slopes is an important issue in both civil and mining engineering.
Rock slope stability accurate structural data collection for use in quarry slope design by m. In a simple design for stability, we want the slope to be stable. A case study from deccan traps, in mahabaleshwar, india has been studied using flac slope 5. Combined rock slope stability and shallow landslide susceptibility. This engineer manual em provides guidance for analyzing the static stability of slopes of earth and rock fill dams, slopes of other types of embankments, excavated slopes, and natural slopes in soil and soft rock. Global stability with relict slip surface in this scenario, the presence of the relict slip surface was assumed.
A comprehensive guide for mining and construction engineers responsible for rock slope stability. Rock slope engineering civil engineering i am menglim. The design of too flat of a highwall angle means considerable additional mining costs. A twolayered slope has a cross section as shown in figure 1 usace 2003 with soil properties as given in table 1. In civil engineering, projects include transportation systems such as highways and railways, dams for power production and water supply, and industrial and urban development. Rock slope stability download ebook pdf, epub, tuebl, mobi.
For an additional 9 years he was a principal advisor to. Stability analysis of rock slopes using the finite element. Pdf new approach for estimating rock slope stability using. The generalized hoekbrown parameters of the slope rock mass are provided in table 1.
Slope stability evaluation and rock mechanics parameter based on. Rock slope stability analysis a variety of engineering activities require excavation of rock cuts. Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes e. This chapter deals with rock slope stability, a subject that has shown remarkable development in the last twenty years relative to methods for estimating shear strength of rock discontihuities and methods of analysis. Rock slope stability th 15th november 2018 chambery, manege conference center the fourth edition of the international symposium rss rock slope stability will be held in chambery, france, from th to 15th november 2018. A slope stability problem in hong kong introduction. Rock slope stability and the design of the appropriate slope angle is extremely important for surface mining in these difficult economic times. The shallow landslide susceptibility analysis involves.
Rockslope stability and longterm equilibrium slope angles are controlled primarily by rockmass properties. Effect of rock bolts geometry of slope with tension crack in upper slope and its interaction with rock bolt. The following table and screen captures summarize the analysis results. It is essential that the engineering geologist be intimately familiar with all of these methods because they provide ways of determining, relatively unambiguously, whether a. Slope stability analyses include static and dynamic, analytical or empirical methods to evaluate the stability of earth and rockfill dams. Estimating slope stability geology and soils information needed from site or soils database check appropriate loading conditions seeps, rapid drawdown, fluctuating water levels, flows select values to input for. The probabalistic sara stability analysis for road access program is still under development. Slope stability, triggering events, mass movement hazards. Rock slope stability and longterm equilibrium slope angles are controlled primarily by rock mass properties. Llewelyn, srk consulting uk ltd a ll hard rock slopes within any quarry excavation should have an appropriate geotechnical design that takes into account the insitu rock mass strength and rock mass structure, with the level. It describes the basic rock slope failure modes and methods of analysisboth kinematic and kinetic techniques. Stability analysis of rock slopes using the finite element method. That is, we want the resistance component r load component q in slope design we know that a fos pdf of input parameters pdf of loads pdf of fos slope. At this scale, the rock slope stability is governed primarily by the geological.
For these conditions, the rupture surface lies predominantly in the weaker materials in the upper part of the slope, and in the stability analysis it is necessary to. Low rock cuts stability analysis of a rock slope in himalayas 3 fig. Rock slope stability of the vmt prince william sound. Analysis of wedge failure with cohesion and friction angle where, ca and cb are the cohesive strength of plane a and b, a and b are the angle of friction along plane a and b, is the unit weight of the rock, and h is the total height of the. In the lecture part of this course we will discuss a variety of methods of analysis of slope stability and instability. Hard rock masses with joints, shears, or bedding representing major discontinuities and dipping downslope are excavated along the dip of the discontinuity, although all material should be removed until the original slope is intercepted. Fhwa nhi06088 6 slope stability soils and foundations volume i 6 3 december 2006 6. Rock slope stability analysis giani, gian paolo on. Rock slope stability analysis lec 1 linkedin slideshare. Slopes in mountainous regions require cohesion 8 undrained short term slope failure in clay. These statistics are confirmed by the authors experience in the analysis of rock fall records over a 19year period on a major railroad in western canada, in which approximately 70 percent of the events occutred during the winter. Symbol parameter dimensions f factor of safety against sliding along sheet joint calculated h height of the overall slope or of each bench 60 m or 20 m respectively.
Pdf several methods for evaluating the stability of rock slopes have been proposed on the basis of site investigation data. Application note slope stability analysis worked example 4. For this purpose, the rock slopes with different dips in the jointed schist rocks were modeled using the phase2 software and their stability were determined using the critical strength reduction factor srf of slopes. Slope stability, triggering events, mass movement hazards factors that influence slope stability gravity the main force responsible for mass movement is gravity.1511 1085 268 419 1182 543 1415 220 1370 249 1333 225 772 374 908 102 767 1301 141 1155 428 64 324 867 221 661 1381 917 1369 1175 1486 1189 775 911 383 973 234 943 1127 1301