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. Slope stability in strong rock 25 mpa based on classification from hungr et al. Soil slope stability analysis 339 isfied for each and every slice, it is also satisfied for the entire mass. Variations in snow strength and stability on uniform slopes. Pdf conventional slope stability analysis usually consists of method originally proposed by fellenius 1936 wherein failure profile of the slope is.
The three simplest structurally controlled failure mechanisms are also the most commonly assessed in rock masses. For infinite slopes that have seepage at the slope face, the factor of safety for slope stability is determined as follows. 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. Soils and foundations testing experience theory lesson 06 chapter 6 slope stability.
The uplifted land would undergo a cycle of erosion where slopes were initially. 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. 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 stability of a natural slope is also important. Pdf numerical methods in analysis of slope stability. How do friction and cohesion work together to stabilize slopes. 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. Downslope component of weight of material including vegetation, fill material, or. The soil and slope properties obtained from the test. Methods for jointed rock slope stability analysis span a very wide range in the simplest form. 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. 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.
Slope stability analysis is performed to assess the potential for failure of the slope by rupture. This study also measured temporal variations in stability in a series of three 900. When they are dry, clayey materials have high shear strength with high cohesion and angle of. Slope stability is the process of calculating and assessing how much stress a particular slope can manage before failing. 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. The slope stability analysis has been prepared in accordance with the. Man made slopes natural slopes are those that exist in nature and are formed by natural causes. Stability analysis of slopes of earth dams soil engineering.
The factor of safety with respect to strength f as expressed in equation. The term landslide refers to a situation of instability affecting natural slopes and involving large volumes of soil. Slope stability studies in the usda forest service have been conducted successfully in accordance with a threelevel concept. One of the softwares that can analyze rock slope stability in a nu. 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.
Detailed pieziometric data at multiple locations and depths within and below the slope will likely be needed. Taylor 1937 conceived the idea of analyzing the stability of a large number of slopes through a wide range of slope angles and. Slopes that are typically assessed fall into a number ofcatego ries,as il lustrated in fig. Slope failure is the movement of mass on slope falls, slides, flows landslide. Slope stability analysis spreadsheet laobing kaisuo. They are certainly major factors in cut slope stability and in the stability of fill slopes involving both internal and external slope failures.
Slope stability evaluations by le and fe methods iii instability of natural and built. This condition is usually analyzed by sectioning the potential. This method of slope stability analysis is based on the assumption that the plane of failure is in the form of a circular arc. System sciences and earth natural hazards stability of. The term slope means a portion of the natural slope whose original profile has been modified by artificial interventions relevant with respect to stability. In the lecture part of this course we will discuss a variety of methods of analysis of slope stability and instability. In geotechnical engineering, the topic stability of slopes deals with. Download pdf 2739 the role of geosynthetics in slope. 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. Paper open access related content reliabilitybased.
The survey discussed the plant groups relevant to slope. Rapid drawdown conditions have been extensively analyzed in the field of dam engineering because reservoir water levels fluctuate widely due to operational reasons. Students will investigate how gravity affects slope stability. Slope stability is affected by the following factors. Slope stability analyses include static and dynamic, analytical or empirical methods to evaluate the stability of earth and rockfill dams. Important aspects in slope stability analysis in this section, three major aspects that influence slope stability analysis are discussed. Slope stability evaluations by limit equilibrium and. Slope stability causes of instability, analysis methods. 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. Stability analysis of finite slopes using the swedish circle method. Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement.
Forces involved for the calculation of stability of slopes. The second is the influence of calculating factor of safety to slope stability and the third aspect is the definition of the slope failure. Slope stability is the resistance of inclined surface to failure by sliding or collapsing. An introduction to slope stability and protection j. Pdf stability of slopes in residual soils semantic scholar. Fundamentals of slope design 2 fundamentals of slope design e. Investigations carried out in sweden on slope failures indicated that the failure surface resembles the arc of a circle. For evaluating the stability of slopes of the affected areas, finite element model fem analysis have been performed using plaxis 2d. An overview on methods for slope stability analysis. 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. 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. Upstream and ds slopes during and immediately after construction.
The extent of the root zone is defined by thedepth of root zone, h r. In particular, slopes are generally steeper and of higher permeability. The engineering design of slopes of manmade slopes in advance a earth dams and embankments. 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. The method satisfies vertical force equilibrium for each slice. 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. First, because of the nature of soils and the geologic environment in which they are found, each slope design is different.
Three test zones were established to evaluate various erosion control materials and methods on the slopes that, in some places, were steeper than 1to1. 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. 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. In addition to varying across space at a given moment in time, stability also changes through time at a given location in space. S f sat u z undrained failures in clay tend to be rotational. A slope is defined as a surface of which one end or side is. The purpose of this activity is for the student to investigate both slope stability and landslides. Numerical analyses methods are the most common ones that are used for rock and soil slope analyses. 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. 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.
Various methods are available for slope stability analysis. Introduction the basic principles for design and construction of stable slopes in soils are quite well known. 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. Fundamentals of slope design keynote address at slope.
The sides of cuttings, the slopes of embankments constructed for roads, railway. 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. How does the slope angle play a role in slope stability. Slopes in mountainous regions require cohesion 8 undrained short term slope failure in clay. 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. Electronic journal of geotechnical engineering 17bund. It is a practical method for the evaluation of the shortterm stability of saturated clay slopes. Stability analysis of finite slopes methods soil engineering.
Analysis capabilities for slope stability have improved markedly in recent years because of the digital computer. The first is about the material properties of the slope model. 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. Stability of finite slopes with plane failure surface o culmanns method. Multiple sources of uncertainties often exist in the evaluation of slope stability. The moment is then calculated about the center of the trial surface. Lecture notes, lectures 1012 stability of slopes studocu. Department of structural engineering geotechnical group 3rd year civil stability of slopes dr. Soil mechanics lecture stability of slopes duration. Chapter 10 slope stability analysis nysdot geotechnical page 1011 january 21, 2014 design manual 10. Examples of common slopes include roads for commercial use, dams, excavated slopes, and soft rock trails in reservoirs, forests, and parks. Methods for analysis of slope stability are described and are illustrated by examples in the appendixes. Pdf stability of slopes and embankments under static load. Fellenius developed a method for stability analysis of a slope assuming a circular failure surface, which is known as the swedish circle method.
Slope stability analyses were performed to assess the likelihood of slides being triggered by gravity, rapid sedimentation underconsolidation and earthquakes. The failure of a mass of soil located beneath a slope. Today, there are several methods for slope stability analysis, each has its own advantages and disadvantages. Construction activities such as excavation of slopes and filling of slopes. Application of the finite element method to slope stability.
Slope stability lesson 06 topic 1 stability analysis of slopes. Slope stability analysis is performed to assess the safe design of a humanmade or natural slopes e. Design of overall slope angle and analysis of rock slope. 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. 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. Assessment of overall stability of retaining walls, including global. 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. This paper aims an overview on various methods of slope stability on the basis of assumptions, factor of safety. For an additional 9 years he was a principal advisor to. The engineering properties of soils as they relate to slope stability are generally understood. Level i, the most general, is conducted for watershed analyses, ecosystem management support, and timber sale area planning. Corestones at the slope face clayinfilled relict joint parallel to the slope face relict joint surfaces within weak matrix fig.
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. 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. Epr fsar includes the following col item for section 2. Epr design certification will evaluate sitespecific information concerning the stability of earth and rock slopes, both natural and manmade. Slickensided black seam on the surface of a relict joint plane. If different strata are present strata boundaries are assumed to be parallel to the surface.
The stability of slopes of earth dams is checked under the following conditions. The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering and engineering geology. When the reservoir on the us side of the earth dam is. Slope and excavation stability analyses are used in a wide variety of geotechnical engineering problems, including, but not limited to, the following. 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. Theory of slope stability kenneth m cruikshank portland state. 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. The slope length depends on the height of the dam or embankment. The number of equations of equilibrium available depends on the number of slices n and the number of equilibrium conditions that are used. Slope stability is an extremely important consideration in the design and construction of earth dams. The stability of slopes is analyzed by comparing the. Sayed mohamed elaraby associate professor in geotechnical. 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.
796 170 1286 511 121 55 70 1031 233 582 915 404 879 1316 867 224 878 1132 1284 289 1599 1528 484 407 878 796 1520 58 160 553 1147 1223 911 1053 445 101 486 1130 1328 1151 293 3 431 1340 1047 1454