Shear band propagation analysis of submarine slope stability software

Not all slope stability software is real expensive. The slope failure mechanism is examined using the concept of shear band propagation. Using shear strength reduction method for 2d and 3d slope. System sciences factors affecting seismic response of. Simslope stands for simplified slope stability analysis software. Simulation accuracy analysis of slope stability based on. Application of the shear band propagation method to slope. Stability analysis method for rock slope with an irregular. Lee and edwards, 1986, reduces the earthquake acceleration time history to an equivalent inertial force acting statically on the potential slope wedge.

Based on the finite element software abaqus, the strength reduction method has been introduced to submarine slope stability evaluation. So, submarine slope stability evaluation is not only an important link of the construction safety guarantee and soil mechanics in the new field of ocean direction, but also the development of energy demand. A slope does not fail if the applied shear stress is less than the residual shear strength gilbert et al. The software in general is very good and ties in well with the way we do things here. Slope is an everyday engineering tool which is quick and easy to use for a wide range of slope stability problems. Xflr5 xflr5 includes the xfoil program for foil analysis, and several 3d analysis methods for planes. It may also revolutionize routine slope stability analysis. Shear strength for slope stability analysis fattdad geotechnical 6 jun 17 11. Application of the shear band propagation approach to the. These criteria can be used can be used with any of the the three methods of stability analysis within galena, and can all be used within the one model, thereby allowing comprehensive stability assessments of both. Shearnormal stress relationships data representing linear, curvilinear, or similar relationships can be entered or imported. I do slope stability analysis for the mining industry and mainly use two, 2d limit equilibrium analysis programs. Here the interest is on the propagation of a shear band from the tip of the initial crack and on the relationship between the principal features of the shear band propagation and the velocitytime profiles recorded at the rear surface of the cracked plate.

Results show that the shear band propagation approach successfully predicts observed failure geometries and suggests triggering conditions from a lower magnitude seismic event compared to that predicted using limiting equilibrium. An important orginal point in the proposed method is that the slope failure is defined according to the shear strain failure criterion. Slope stability refers to the condition of inclined soil or rock slopes to withstand or undergo movement. It can be seen from figure 6 that the normal stress mainly concentrates on the lower part of the interface.

Suzuki and yamashita 2008 or a transition to a ratedependent steadystate porosity segall and rice 1995, bizzarri and cocco 2006. Figure 6 gives the distribution of normal stress and shear stress on the interface. For phase2 software, there are four kinds of element type, including threenode triangle, sixnode. Deterministic and probabilistic analyses are possible. The slip surface is considered as circular bishop, felleniuspetterson, janbu, morgensternprice or spencer methods or polygonal sarma, janbu, morgensternprice or spencer methods. Introduction methods for analyzing stability of slopes include simple equations, charts, spreadsheet software, and slope stability computer programs. The stability analysis of underwater slopes based on. In this project the phenomenon of shear band propagation and its effect on submarine slope stability is investigated. Flac slope is a special, streamlined version of flac for evaluating the factor of safety fos of soil and rock slopes in two dimensions with simple and fast model setup and analysis execution. Criteria for planar shear band propagation in submarine.

Flacslope can simulate stability problems under a wide variety. Appendix d discusses shear strength value selection. Once deformation takes place and the weak zone exceeds a critical length, a shear band may propagate into the adjacent slope and can initiate retrogressive slope failure fig. Ge, principal consultant with gregory geotechnical gregeo. Fully softened shear strength is an important empirical engineering concept for slope stability analyses of cuts in stiff clays and compacted embankments constructed of highplasticity clays. Slope stability is a major concern for geotechnical and mining engineers worldwide, and consequently, a great deal of effort at rocscience is dedicated to slope stability analysis software. A result is that an explanation of the conditions leading to failure can be attributed to many submarine landslides.

Software, lem, fem, slope stability, plaxis analysis of slope stability when it is subject to various types i. This program is used to perform slope stability analysis embankments, earth cuts, anchored retaining structures, mse walls, etc. A nonlinear mathematical model for postpeak degradation of undrained shear strength of sensitive clay, applicable to small to largestrains, is proposed in this study based on available experimental results. To compare the velocity of propagation of the band predicted by eq. Submarine slope failures due to pipe structure formation. Shear strength reduction method ssr advantages and disadvantages of lem and ssr shear strength reduction outline applications soil models mse wall slope with supports 3d effect on slope stability analysis. The future application of shear band propagation theory to submarine landslide analysis is also discussed. The shear strength reduction technique of finite element slope stability analysis is a simple approach that involves a systematic search for a strength reduction factor srf or factor of safety value that.

Use of residual shear strength parameters for slope. Analytical and numerical modeling of progressive failure of. Shear strength reduction finite element technique finite element fe analysis is now widely accepted in routine excavation and support design and analysis. With a probabilistic analysis you can take into account variations in material. The goal of this research is formulating analytical criteria for the catastrophic shear band propagation for true threedimensional slope geometries. Pseudostatic seismic slope stability analysis, combined with the in. Analysis of increasing shear strength of soil to slope stability after consolidation settlement completed with various method yudhi lastiasih and putu tantri k. Software for slope stability analysis dirt dauber geotechnical 1 dec 16 17. Modeling slope instability as shear rupture propagation in. The limit equilibrium method is the most common approach for analyzing slope stability in both two and three dimensions. Transition from shear band propagation to global slab. This concept has been used to explain many firsttime failures for which the back calculated shear strength is below the peak strength measured in the. The purpose of this project was to investigate slope stability and shear strength in deep water. Shear band propagation is an effective mechanism to explain large landslides observed in the sediment record.

Finite element analysis of rock slope stability using shear. Submarine slope stability executive summary background and context oil and gas developments often require placing equipment, e. Oasys slope twodimensional slope stability analysis. The stability condition of slopes is a subject of study and research in soil mechanics, geotechnical engineering and engineering geology.

With the same finite element model, the safety factors of the land slope and submarine slope are respectively 1. The user interface and analysis options are almost identical to the generalised slope analys is module except for the ability to define a slip surface of any general shape. Existing criteria for catastrophic shear band propagation in submarine slopes are either restricted to plane strain conditions or valid only for planar slopes. Slopew can effectively analyze both simple and complex problems for a variety of slip surface shapes, porewater pressure conditions, soil properties, and loading conditions. Research paper seismic slope stability analysis of kaswati earth dam 1patel samir k. The stability analysis of underwater slopes based on strength. The presented method can obtain not only the detailed stability status at any grid node of a complex shear plane but also the global safety of the slope. The graphics and the pointandclick data input are also very good and makes the program very easy to use. Based on the finite element software abaqus, the strength reduction method has been introduced to submarine slope stability. A41 back calculation method to estimate shear parameter c and of cililin, west java landslides ikah n. With the exception of the pile bearing capacity module, all modules can perform deterministic analyses as well as a probabilistic analyses.

Leame limit equilibrium analysis of multilayered earthworks is the most recent version of software, previously known as reame rotational equilibrium analysis in multilayered. Shear strength for slope stability analysis slope stability. Rice abstract when a region of intense shear in a slope is much thinner than other relevant geometric lengths, this shear failure may be approximated as localized slip. Submarine slope stability forecasting and back analyses in. Of the software which is currently available from rocscience, half of all programs are either specifically dedicated to slope stability analysis ie. Implementation of a large deformation finite element. Finite element analysis of rock slope stability using. Abstract when a region of intense shear in a slope is much thinner than other relevant geometric lengths, this shear failure may be approximated as localized slip, as in faulting, with strength determined by frictional properties of the sediment and effective stress normal to the failure surface. The aim of this study was to demonstrate that a slope needed to be analyzed in many different directions in order to assess its stability conclusively, rather than using just one crosssectional profile to represent the entire slope. The research is based on the concepts of shear band propagation approach which finds its fundamentals in energy balance considerations of fracture mechanics. Accuracy analysis, slope stability, shear strength reduction, finite element method, factor of safety. Slope stability analysis slope w is the leading slope stability software for soil and rock slopes. Software for slope stability analysis slope stability.

Research paper seismic slope stability analysis of. Also a brief introduction and working principles of the software is discussed. It can be used mainly for preliminary analysis of slopes since it can provide an estimate of the factor of safety with minimum effort from the user. Much attention has been paid over the last two decades to unidirectional parallel to the travel direction of sliding mass shear band propagation sbp related. Use of fully softened shear strength in slope stability. Flac slope can simulate stability problems under a wide variety. Sanghvi address for correspondence 1applied mechanics department, 2professor, l. However the minimum constructive elements provided in the program do not allow the software to perform analysis for complex cases. Analyzing slope stability by the limit equilibrium method provides a pcbased software program for performing slope stability analyses, along with supporting documentation. Work on this project was broken up into computational investigations of simple, hypothetical slopes and stratigraphies, and more complex, irregular slopes based on actual bathymetry from offshore surveys. Oasys slope twodimensional slope stability analysis software. An approach for calculating distributed factor of safety of the irregular shear plane was put forward in this paper. Pdf effects of shear band propagation on submarine landslide. Modeling slope instability as shear rupture propagation medium 217 slipproportional porosity change rice 1980.

Other work has examined slip propagating quasistatically or. Slope performs twodimensional slope stability analysis using the slices methods and presents the results in a clear graphical format. Submarine landslide can destroy various engineering facilities. Simulation accuracy analysis of slope stability based on finite element shear strength reduction ssr method. Soils and foundations testing experience theory lesson 06 chapter 6 slope stability. Economics could be improved by steepening the slope thereby reducing the amount of waste excavation. Introduction methods for analyzing stability of slopes include simple. The basic software module deals with unreinforced slope analysis using bishops simplified method and circular slip surfaces. Comparing the consequences, the sliding planes and safety factors agreed well with the result of limit. The commercial limit equilibrium programs all do the basics i. With an increase in k h, the shear band propagation occurs mainly on the left side of point a and reaches the downslope ground surface fig. Gigantic submarine landslides pose a significant threat to offshore infrastructures and may be initiated by an inconspicuous weakened zone, followed by catastrophic shear band propagation under the effect of strain softening. Features material strength criteria slope stability analysis. Seepage and slope stability analysis of earth dams, levees, excavations, embankments, and natural slopes.

Shear band propagation analysis of submarine slope stability finiteelement analysis of a deep excavation case history source. Submarine slope stability evaluation based on strength. The maximum normal stress appears at the transition area where the slope of the shear plane changes from steep to gentle. Permanasari, gunawan handayani, arif rohman and lilik hendrajaya a51. Modeling slope instability as shear rupture propagation in a saturated porous medium r.

The factors, which mainly influence the stability of a typical open. Slope stability analysis of soil slopes using the nonvertical slice method proposed by sarma noncircular slip. By definition, the factor of safety of a slope is the ratio of actual soil shear. Slope stability software geotechnical engineering 101. The slope failure mechanisms are examined using the concept of shear band propagation. Modeling slope instability as shear rupture propagation in a. Choice of slope stability software is very personal. Fundamentals and methods presents basic principles for the safe design of constructed or natural earth slopes. Shear band propagation analysis of submarine slope.

Slopes need be designed and cut with a margin of safety for open pit mines. Analytical and numerical modeling of progressive failure. In this paper a model is proposed for postpeak strain softening behavior of marine sensitive clay. Slope w can effectively analyze both simple and complex problems for a variety of slip surface shapes, porewater pressure conditions, soil properties, and loading conditions. This approach covers a wide variety of potential failure mechanisms, such as slab failures, spreadings, ploughings and runouts, and provides analytical energy balance criteria for predicting their occurrence. Flacslope is a special, streamlined version of flac for evaluating the factor of safety fos of soil and rock slopes in two dimensions with simple and fast model setup and analysis execution. Shear band propagation analysis of submarine slope stability. Present methods for stability analysis of underwater slopes are mostly confined to laboratory experiments and limit equilibrium method. Seepage and slope stability analysis graduate studies. Shear band propagation from a crack tip sciencedirect. Jul 12, 2017 the factors, which mainly influence the stability of a typical openpit slope, are the shear strength parameters of slope forming material, the presence and characteristics of discontinuities in the slope mass and the groundwater conditions singh and monjezi 2000. Use of residual shear strength parameters for slope stability. Slope stability analyses include static and dynamic, analytical or empirical methods to evaluate the stability of earth and rockfill dams, embankments. The paper summarises recent developments in the shear band propagation approach, which enables simplified submarine slope stability analysis to account for catastrophic and progressive failure.

Threedimensional spreading finiteelement simulation. Slope stability analysis using limit equilibrium method lem vs. The prokon geotechnical analysis suite comprises a number of modules for analysis stability and determining capacity. The shear band propagation approach offers an alternative view, where an initial small failure can grow into a larger failure at the point of initiation. The equivalent plastic shear strain distribution for k h 0. Slope stability analysis slopew is the leading slope stability software for soil and rock slopes. Shear normal stress relationships data representing linear, curvilinear, or similar relationships can be entered or imported. Cads reslope is a leading slope stability software package for calculating the factor of safety of earth slopes. The aim of this paper is to verify the shear strength reduction technique for the finite element slope stability analysis. Residual shear strength of a soil represents the lowest possible shear strength that a soil exhibits at large shear strains and this mobilized strength plays a significant role in the stability analyses. Submarine slope failures can occur in such areas and create soil slides. Slope stability analysis by the limit equilibrium method.