Stability analysis of reinforced slopes sciencedirect. The term slope means a portion of the natural slope whose original profile has been modified by artificial interventions relevant with respect to stability. Slope stability evaluations by le and fe methods iii instability of natural and built. Hunter, department of civil engineering, virginia polytechnic institute and state university. 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. A gisbased 3d slope stability analysis method based on. The following data and characteristics of the slope materials were utilized in the analysis. Hounsa hebei university of technology, tianjin, china abstract the stability of earthworks cuttings, embankments, dikes and natural slopes is a problem that is of concern to geotechnicians, both practitioners and researchers. Slide2 most comprehensive 2d slope stability software. Soil mechanics and foundation engineering report, technical university of norway, trondheim. A slope is an inclined boundary surface between air and the body of an earthwork such as highways, cut or fill, railway cut or fill, earth dams, levees and river training work. Forces involved for the calculation of stability of slopes.
Comparison of slope stability methods of analysis1 received october 12, 1976 accepted april 4, 1977 the papercompares six methods ofslicescommonly sed for slopestability analysis. Using the finite element analysis method and the autorefine search method in slide, run the groundwater and slope stability analysis on the model. Macslope slope stability analysis for the mac os desktop. Macslope is an app designed to calculate and search for the critical factor of safety of earth slopes, using common methods of limit equilibrium slope stability analysis. Recall modes of slope failureexplain effects of water on slope stability discuss slope stability circular and block. Evaluation on the stability of slope at faculty of. The first to make a valid slope stability analysis possible through use of simple charts and simple equations was taylor 9. Figure 3 illustrates the location of the two 2 slope sections that were analyzed for slope stability. Most slope stability analysis computer programs are based on the limit equilibrium concept for a twoor threedimensional model. Soils and foundations testing experience theory lesson 06 chapter 6 slope stability. An analysis of slope stability begins with the hypothesis that the stability of a slope is the result of downward or motivating forces i. The steps involve in solving the model of the slope were drawn, defined and assigned accordingly before the final analysis is being carried out in accordance to the methodology of the slope w 2007 software. Analysis of road embankment slope stability chunyuan liu, ulysse seho f.
Reliability analysis of slope stability using monte carlo. Soil slope stability analysis analyses of slopes can be divided into two cat egories. A limit equilibrium slope stability analysis code for. Cheng y m and yip c j 2007 threedimensional asymmetrical slope stability analysis extension of bishops, janbu s, and morgensternprices techniques, asce journal of geotechnical and geoenvironmental engineering. The failure of a mass of soil located beneath a slope is called as slide. Low efficiency and unreliability are the problems commonly encountered. This program is used to perform slope stability analysis embankments, earth cuts, anchored retaining structures, mse walls, etc. Slope stability analysis should consider the cases of shortterm and long.
Stability analysis by the method of slices and inclusion of reinforcement forces. Schuster, department of civil engineering, university of idaho this paper compiles practical chart solutions for the slope stability prob. The xstabl reference manual is intended to provide information about the interactive features that allow the user to prepare data files and perform a slope stability analysis. Conventional methods of slope stability analysis can be divided into three groups. Simplicity and relatively good results are the advantages of these methods. Pdf slope stability analysis methods danial salajegheh. Slope stability united states army corps of engineers. Model complex geometries, pore pressure conditions, tension cracks, surcharge loads, and seismic loading. Summary of root strength data for live sugar maples. There are also questionable assumptions regarding the forced application of the assumed factor of safety to each slice of the analysis during the iteration process.
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 analysis of reinforced slopes 415 stability equations. 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. The next six chapters of the reference manual provides details concerning the following topics. Slope stability analysis of peat landslides has been undertaken in relatively few cases. In stability analysis of threedimensional slope, the direction of the shear stress in the elemental column is usually assumed to be parallel to the xz plane, therefore a3 substituting eqs. Pdf assessment of 3d slope stability analysis methods based on. Construction of road embankment with varied heights is constantly carried out in china.
Slide2 is a powerful, userfriendly, 2d slope stability analysis program using limit equilibrium method. Slope stability evaluations by limit equilibrium and. The methods that had optimal performance for the analyzed conditions were the simplified bishop, the simplified janbu and the bishop methods. Petersonpuritan ou2 stability analysis december 2003 shield engineering, inc. The analysis results showed that the presence of high water level ri 4. What i am having trouble determining is the merits of each and when one method would prove more applicable than. The factor of safety equations are written in the same form, recognizing whether moment and or force equilibrium is explicitly satisfied.
The moment is then calculated about the center of the trial surface. Soil slope stability analysis 339 isfied for each and every slice, it is also satisfied for the entire mass. Chart solutions for analysis of earth slopes john h. Boutrup and love11 1980 presented a strategy that included random generation of slip surfaces and repeated comparisons of calculated factors of safety. It is essential that the engineering geologist be intimately familiar with all of these methods because they provide ways of.
The method satisfies vertical force equilibrium for each slice. Bs, janbu simplified js and janbu gps methods are compared with the. The slip surface is considered as circular bishop, felleniuspetterson, janbu, morgensternprice or spencer methods or polygonal sarma, janbu, morgensternprice or spencer methods. The idea of discretizing a potential sliding mass into slices was introduced early in the 20th century. The current study 14 16 extended the 2d hovland model, bishop model and janbu model to 3d models. Slope stability causes of instability, analysis methods. In this method, the potential failure surface is assumed. What are the resulting factors of safety bishop, spencer, janbu corrected and janbu simplified. Chapter 10 slope stability analysis nysdot geotechnical page 1011 january 21, 2014 design manual 10.
Methods of slope stability analysis o limit equilibrium method o limit analysis method o numerical methods we will consider only the limit equilibrium method, since it is the oldest and the mostly used method in practice. A slope is defined as a surface of which one end or side is. The slopes were chosen based on proximity to boring locations and also areas of steep slope to yield worst case scenario conditions. Fellenius, bishop, simplified bishop, simplified janbu, spencer. A2, and noting that is always positive, and can be calculated using a4a a4b. Fhwa nhi06088 6 slope stability soils and foundations volume i 6 3 december 2006 6. Difference between simplied janbu and bishop slope.
The number of equations of equilibrium available depends on the number of slices n and the number of equilibrium conditions that are used. The routine procedure includes comparing a number of admissible surfaces that are basically selected by random searches. This method of slope stability analysis is not widely used since it has been. Slide2 includes builtin finite element groundwater seepage analysis, probabilistic analysis, multiscenario modeling, and support design. Where this has been done, the peat failure is usually treated as a translational planar slide and a simple infinite slope analysis is used to back calculate strength parameters of the slope at the time of failure hendrick, 1990. A simplified geometry is used for the back analysis calculations figure 3. Learning outcomes gat the end of this session, the participant will be able to. These conditions are described in the revised geotechnical report prepared for the project, and graphically displayed on the stability model outputs attached to this narrative. Pore pressure due to seepage through the fill reduces the stability of the slopes, but static water pressure. Slope stability analysis limit equilibrium or the finite. Table 2 provides a summary of the factors of safety that were obtained in this analysis.
Detailed pieziometric data at multiple locations and depths within and below the slope will likely be needed. In 1916, petterson 1955 presented the stability analysis of the stigberg quay in gothenberg. Methods for analysis of slope stability are described and are illustrated by examples in the appendixes. Slope failure is the movement of mass on slope falls, slides, flows landslide. This paper explores the feasibility of using optimization methods to search for the minimum factor of safety in slope stability analysis. They are certainly major factors in cut slope stability and in. Studies have investigated the combination of gis and mechanical model.
Pdf importance of slope stability problem is the reason why so many alternate methods have been developed for evaluating the safety of a slope. Results method factor of safety bishop simplified 1. Slope stability analyses include static and dynamic, analytical or empirical methods to evaluate the stability of earth and rockfill dams, embankments. Table 2 results of liner stability analyses factor of safe janbu static attachment a existin conditions 1. Reliability of slope stability is frequently measured by reliability index, and slope failure probability, p f, which is defined as the probability that the minimum. Pdf performance of analysis methods of slope stability for different. Slope stability evaluations by limit equilibrium and finite. Stability of slopes is usually analyzed by methods. The following table and screen captures summarize the analysis results. A finite element approach of stability analysis of internal dump slope in wardha valley coal field, india, maharashtra. Slope stability verification manual deep excavation llc page 11 e. The slope stability analysis is crucial in engineering practice to ensure the stability of structures and prevent loss of human life and money. Theory of slope stability kenneth m cruikshank portland state.
Slope, a limit equilibrium slope stability analysis program, was used. Analyzing the stability of earth structures is the oldest type of numerical analysis in geotechnical engineering. The comparative study among the le methods shows that bsm is as good as m. Janbu s 1973 and sarmas 1979 methods of slices to calculate the stability of the slope have been used to back. This method of slope stability analysis is based on the assumption that the plane of failure is in the form of a circular arc. Construction of embankment is not infrequently done over a relatively incompressible soft soil consistency. Reliability analysis of slope stability has attracted considerable research attention in the past few decades 610. The quantitative determination of the stability of slopes is necessary in a number of engineering activities, such as. This method is most primitive in the area of optimization. Geotechnical soil and rock design parameters are required for slope stability analysis with strength parameters developed using methodologies presented in chapter 5 and the other referenced publications in section 7. Rock slope engineering civil engineering i am menglim. Macslope brings fully featured slope stability analysis to the mac os desktop. Although stability and movement are closely re lated, two different and distinct types of analyses are almost always used to evaluate them.
The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering and engineering geology. Slide2 can be used for all types of soil and rock slopes, embankments, earth dams, and retaining walls. The term landslide refers to a situation of instability affecting natural slopes and involving large volumes of soil. Investigation of bishops and janbus models capabilities. Evaluation of minimum factor of safety in slope stability.
The groundwater analysis is run first, followed by the slope stability analysis. Bakers approach 1980 employed dynamic programming, which, as. Thus, they can be used as alternative methods to replace the spencer method in the analysis of slope stability on earth dams. What i am having trouble determining is the merits of each and when one method would prove more applicable than the other. The method of stability analysis used see section 6. Janbu method is similar to the bishop method in that it includes the interslice normal in. This offers a number of methods but, for each analysis, the bishop method was applied for ease of comparison with the fe analysis. Bvs viswanadham, department of civil engineering, iit. Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement. Unfortunately, these chart solutions have been published in. An overview on methods for slope stability analysis.
I understand that in bishop slope stability analysis we are determining a fs based on moment equilibrium. It is a practical method for the evaluation of the shortterm stability of saturated clay slopes. Limit equilibrium slope stability analysis using the. With the advent of highspeed electronic computers, other generalized solutions wilh different basic assumptions have been obtained and published. Therefore, the 3d slope stability analysis model can be established based on grid column units. Determination of slope safety factor with analytical solution and. 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 analyseswere performed for the cross section shown in figure 1. Methods of analysis which employ noncircular slip surfaces include.