In geotechnical engineering, the topic stability of slopes deals with. The method satisfies vertical force equilibrium for each slice. Fundamentals of slope design 2 fundamentals of slope design e. In addition to the threelevel method, this guide discusses the forest planning process, geomorphology, channel processes and sediment budgets, climatology, soil and rock mechanics, hydrogeology, exploration and testing methods, and risk analysis as they apply to slope stability. The stability of slopes is analyzed by comparing the. The slope stability analysis has been prepared in accordance with the. This method of slope stability analysis is based on the assumption that the plane of failure is in the form of a circular arc. Slope stability evaluations by limit equilibrium and. Assessment of overall stability of retaining walls, including global. The soil and slope properties obtained from the test.
Slope stability analysis is performed to assess the potential for failure of the slope by rupture. Downslope component of weight of material including vegetation, fill material, or. In addition to varying across space at a given moment in time, stability also changes through time at a given location in space. Sayed mohamed elaraby associate professor in geotechnical.
Slope stability is an extremely important consideration in the design and construction of earth dams. S f sat u z undrained failures in clay tend to be rotational. In the lecture part of this course we will discuss a variety of methods of analysis of slope stability and instability. Analysis slope stability of earthen dam for different conditions infinite slopes have dimensions that extended over great distances and the soil mass is inclined to the horizontal. Level i, the most general, is conducted for watershed analyses, ecosystem management support, and timber sale area planning. Soils and foundations testing experience theory lesson 06 chapter 6 slope stability. Students will investigate how gravity affects slope stability. Today, there are several methods for slope stability analysis, each has its own advantages and disadvantages. Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement. Pdf stability of slopes in residual soils semantic scholar.
Detailed pieziometric data at multiple locations and depths within and below the slope will likely be needed. Stability analysis of slopes of earth dams soil engineering. Slope failure is the movement of mass on slope falls, slides, flows landslide. Stability indications from surface features of slopes it is probably true that most assessments of the stability of a natural slope are based 80% or more on a to d above and less than 20% on analytical procedures. Examples of common slopes include roads for commercial use, dams, excavated slopes, and soft rock trails in reservoirs, forests, and parks. Slope stability is the process of calculating and assessing how much stress a particular slope can manage before failing. For evaluating the stability of slopes of the affected areas, finite element model fem analysis have been performed using plaxis 2d. Investigations carried out in sweden on slope failures indicated that the failure surface resembles the arc of a circle. Free download slope stability analysis spreadsheet, method of slices slope stability analysis, slope stability analysis software free download, slope stability analysis examples, ordinary method of slices spreadsheet, slope stability analysis methods pdf, factor of safety calculation for slope stability, swedish method of slices example, slope analysis pdf, incoming search terms. Slopes and static stability enae 788x planetary surface robotics u n i v e r s i t y o f maryland rover with cg and force vector 2 mg c. The engineering properties of soils as they relate to slope stability are generally understood. Slope stability causes of instability mechanics of slopes analysis of translational slip analysis of rotational slip site investigation remedial measures soil or rock masses with sloping surfaces, either natural or constructed, are subject to forces associated with gravity and seepage which cause instability. Important aspects in slope stability analysis in this section, three major aspects that influence slope stability analysis are discussed.
Design of overall slope angle and analysis of rock slope. Steepest slopes at the beginning of the process with a progressively decreasing angle over time to give a convex upper slope and a concave lower slope changes over time assumed a rapid uplift of land with an immediate onset of denudation. One of the softwares that can analyze rock slope stability in a nu. Chapter 4 slope stability universiti teknologi malaysia. Theory of slope stability kenneth m cruikshank portland state. Slope stability is affected by the following factors.
The survey discussed the plant groups relevant to slope. An overview on methods for slope stability analysis. The stability of a natural slope is also important. Physical properties of soil and its implication to slope. If different strata are present strata boundaries are assumed to be parallel to the surface. Stability analysis of finite slopes using the swedish circle method. Numerical analyses methods are the most common ones that are used for rock and soil slope analyses.
Material and method in order to establish and characterize the problem nature of the slope material in terms of its implications for slope stability, a range of analysis were carried out at the geotechnical laboratory, department of earth sciences, manipur university. 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. Methods for jointed rock slope stability analysis span a very wide range in the simplest form. The exercise consists of creating sand and gravel mountains, measuring slopes, and testing the effects of water on slope stability. 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 conventional slope stability analysis usually consists of method originally proposed by fellenius 1936 wherein failure profile of the slope is. The engineering design of slopes of manmade slopes in advance a earth dams and embankments. Epr fsar includes the following col item for section 2. Stability of finite slopes with plane failure surface o culmanns method. Pdf cracks are a common occurrence in soil slopes, and a method is described for including the presence of cracks in stability assessment based on the.
First, because of the nature of soils and the geologic environment in which they are found, each slope design is different. Slope stability studies in the usda forest service have been conducted successfully in accordance with a threelevel concept. Paper open access related content reliabilitybased. Slope stability analysis is performed to assess the safe design of a humanmade or natural slopes e. They are also likely to be more heterogeneous and thus less amenable to analytical assessment than slopes in sedimentary. In addition to introducing some solutions that may be unfamiliar, this compilation pro vides a quick means of locating various solutions so that rapid comparisons of advantages and disadvantages of each solution can be made. Stability analysis of finite slopes methods soil engineering. Corestones at the slope face clayinfilled relict joint parallel to the slope face relict joint surfaces within weak matrix fig. Slopes in mountainous regions require cohesion 8 undrained short term slope failure in clay. When they are dry, clayey materials have high shear strength with high cohesion and angle of. Slope stability analysis geotechnical design manual m 4603 chapter 74 december 2006 slope stability analysis detailed assessment of the groundwater regime within and beneath the slope is also critical. Taylor 1937 conceived the idea of analyzing the stability of a large number of slopes through a wide range of slope angles and.
The purpose of this activity is for the student to investigate both slope stability and landslides. Construction activities such as excavation of slopes and filling of slopes. An introduction to slope stability and protection j. The slope stability assessment in this report is based on subsurface conditions in the boreholes, the observations during our site visits, and the slope profiles provided by the client. Pdf stability of slopes and embankments under static load. Methodology of slope stability analysis it is a method to expresses the relationship between resisting forces and driving forces driving forces forces which move earth materials downslope. Department of structural engineering geotechnical group 3rd year civil stability of slopes dr. The sides of cuttings, the slopes of embankments constructed for roads, railway. Second, the basic mechanics applied to estimate the stability of a cut slope in soil are the same as those used to estimate the stability of a fill slope.
Three test zones were established to evaluate various erosion control materials and methods on the slopes that, in some places, were steeper than 1to1. Fs slope stability analysis geotechnical design manual m 4603 chapter 74 december 2006 slope stability analysis detailed assessment of the groundwater regime within and beneath the slope is also critical. Phase i, the preparation work done prior to the installation of the various erosion control systems, included removal of large rocks from the slopes and construction of drain. This paper examines and discusses a number of factors that make slope stability assessments, and slope engineering in residual soils somewhat different from sedimentary soils. 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. Fundamentals of slope design keynote address at slope. 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.
Various methods are available for slope stability analysis. Slope stability is the resistance of inclined surface to failure by sliding or collapsing. Slope stability analysis spreadsheet laobing kaisuo. For infinite slopes that have seepage at the slope face, the factor of safety for slope stability is determined as follows. Electronic journal of geotechnical engineering 17bund. Stability region rover is stable so long as gravitational force vector passes inside the stability region formed by the contact points of the suspension with the ground. Slickensided black seam on the surface of a relict joint plane.
Lecture notes, lectures 1012 stability of slopes studocu. Soil mechanics lecture stability of slopes duration. The term slope means a portion of the natural slope whose original profile has been modified by artificial interventions relevant with respect to stability. This study also measured temporal variations in stability in a series of three 900. A slope is defined as a surface of which one end or side is. Chapter 10 slope stability analysis nysdot geotechnical page 1011 january 21, 2014 design manual 10. Parametric studies are conducted and the results are used to develop a set of stability charts that can be used to assess the contribution of root reinforcement on slope stability. When the reservoir on the us side of the earth dam is. Variations in snow strength and stability on uniform slopes. Application of the finite element method to slope stability. The uplifted land would undergo a cycle of erosion where slopes were initially. This condition is usually analyzed by sectioning the potential.
Analysis capabilities for slope stability have improved markedly in recent years because of the digital computer. The slope stability analysis was performed using the simplified bishop method of slices to discretize the soil mass to establish the minimum factor of safety of the slope. Slope stability analyses include static and dynamic, analytical or empirical methods to evaluate the stability of earth and rockfill dams. The term landslide refers to a situation of instability affecting natural slopes and involving large volumes of soil. They are certainly major factors in cut slope stability and in the stability of fill slopes involving both internal and external slope failures. 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. For an additional 9 years he was a principal advisor to. Slope stability analyses were performed to assess the likelihood of slides being triggered by gravity, rapid sedimentation underconsolidation and earthquakes. System sciences and earth natural hazards stability of.
The slope length depends on the height of the dam or embankment. How does the slope angle play a role in slope stability. Fellenius developed a method for stability analysis of a slope assuming a circular failure surface, which is known as the swedish circle method. Rapid drawdown conditions have been extensively analyzed in the field of dam engineering because reservoir water levels fluctuate widely due to operational reasons. How do friction and cohesion work together to stabilize slopes. Download pdf 2739 the role of geosynthetics in slope. The factor of safety with respect to strength f as expressed in equation. Slope stability lesson 06 topic 1 stability analysis of slopes. This engineer manual em provides guidance for analyzing the static stability of slopes of earth and rockfill dams, slopes of other types of embankments, excavated slopes, and natural slopes in soil and soft rock. Vegetation modifies the moisture content of the soil, influencing soil strength, and the presence of roots in the soil increases soil strength and, therefore, its stability. Slope stability evaluations by le and fe methods iii instability of natural and built. Introduction the basic principles for design and construction of stable slopes in soils are quite well known. Soil slope stability analysis 339 isfied for each and every slice, it is also satisfied for the entire mass. Slope stability in strong rock 25 mpa based on classification from hungr et al.
This phase of construction and the installation of the erosion control materials is described in colorado department of transportation report number cdotdtdr966, evaluation of slope. Slope and excavation stability analyses are used in a wide variety of geotechnical engineering problems, including, but not limited to, the following. Multiple sources of uncertainties often exist in the evaluation of slope stability. In particular, slopes are generally steeper and of higher permeability.
Stability analyses of the slopes were carried out using the computer program slide 6 with the bishops method of analysis. Man made slopes natural slopes are those that exist in nature and are formed by natural causes. Cohesive finetextured materials lake siltclay marine siltclay some residual soils and tills stability in cohesive materials is con trolled largely by clay mineralogy and mois ture content of overburden. The first is about the material properties of the slope model. Pdf numerical methods in analysis of slope stability. Epr design certification will evaluate sitespecific information concerning the stability of earth and rock slopes, both natural and manmade. The extent of the root zone is defined by thedepth of root zone, h r. The analyses revealed that it is unlikely that most of the seafloor slope failures were triggered by gravity loads alone. The moment is then calculated about the center of the trial surface. Methods for analysis of slope stability are described and are illustrated by examples in the appendixes.
The stability of slopes of earth dams is checked under the following conditions. This paper aims an overview on various methods of slope stability on the basis of assumptions, factor of safety. Slope stability causes of instability, analysis methods. The referenced june,2000 letter also acknowledged receipt of a proposal dated june 2, 2000, prepared by scs engineers that recommended an appropriate method to determine slope stability. Slopes that are typically assessed fall into a number ofcatego ries,as il lustrated in fig. Request pdf the stability of thawing slopes as a result of recent field exploration and study in the mackenzie river valley between fort simpson and fort good hope, n. The number of equations of equilibrium available depends on the number of slices n and the number of equilibrium conditions that are used. When assessing stability of slopes in the face of uncertainties, it is desirable, and sometimes necessary, to adopt reliabilitybased approaches that consider these uncertainties explicitly. Upstream and ds slopes during and immediately after construction.
The second is the influence of calculating factor of safety to slope stability and the third aspect is the definition of the slope failure. It is a practical method for the evaluation of the shortterm stability of saturated clay slopes. The three simplest structurally controlled failure mechanisms are also the most commonly assessed in rock masses. The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering and engineering geology. Forces involved for the calculation of stability of slopes. 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.