open pit mining, road cuts, etc.) 1. The stability assessment according to block theory on the contrary follows a deterministic procedure. Improvement of slope failure. 0000005774 00000 n Summary A simple formula for plane slope failure is derived, which may be used for the design of … The stability of the rock wedge is controlled by: joint sets dip and dip direction, slope geometry and direction, external forces (including water pressure and earthquake) and rock and joints mechanical properties. The only difference between the translational failure and the wedge failure is that translational failure only occurs in case of infinite slopes but wedge failure can occur in both infinite and finite slopes. x�b```f``z�����U� �� @16�T' g�Cβb,ڜ�*q���?ӥ�L���6�����h�y�.p�v-6���IP�Q�vf��D�9���T�y- �e9E��|�Y��J� b�[y����1�i�\��=�.#�69e"Pd��� �ƀe ���x� %PDF-1.3 %���� Dilatancy in a rock mass is unconstrained near slopes as normal stress on joints is small due to weight of the wedge. We will introduce a few types of slope failure that are common in soils. Recently, the factor of safety of rock slopes against the wedge failure … It is believed that the study can enhance the way for stability analysis and monitoring of the potential failure of jointed rock slopes.Keywords: Wedge failure; Joint persistence; Groundwater; Rock … These failure modes pro-vide a basis for the formulation of limit state functions so the prob-lem of stability of individual wedges in rock slopes is considered. Failure of a rock slope on one or two plane surfaces is the simplest but at the same time the most important type of sliding failure and forms the basis for the stability analysis of rock slopes. The only difference between the translational failure and the wedge failure is that translational failure only occurs in case of infinite slopes but wedge failure can occur in both infinite and finite slopes. The stability of a particular rock slope is governed by three main engineering geologic factors, KEYWORDS Figure 2 shows the wedge failure phenomena in a rock slope. It happens that in some places rock slope failures were so heavy at one spot, and it took place on both sides of the road and blocked it (Fig. increases more complex mechanisms such as step-path failuresand rotational shear failure , which the study of the wedge failure, which occurs as sliding of a mass of rock on two intersecting planes, generally discontinuity planes. 0000001203 00000 n The rock type was a very competent, massive granite ROCK SLOPES MODELING Location of the stations along the Werka descent is traced by the GPS. 45-03 Building 406 Of 202. Multiple failure surfaces usually occur and change continuously as flow proceeds. The required criteria for wedge failure … Kinematic Analysis – Rock Slope Wedge Failure Similar to planar failures, seve ral conditions relating to the line of intersection must be met for wedge failure to be kinematically admissible : (i) The dip of the slope must exceed the dip of the line of intersection of the two wedge forming discontinuity planes. 0000000656 00000 n 0000005876 00000 n In this code only one mode that is plane wedge failure ls described (see Fig. Eng Geol 202: 55-61 [22] Smith JV. Note: The application Rock Slope can evaluate a broken rock wall by a shear failure (rock slides) using a planar and/or a polygonal shear plane and a rock wedge. E-mail: Professor, Dept. Wedge Failure Wedge failure can occur in rock mass with two or more sets of discontinuities whose lines of intersection are approximately perpendicular to the strike of the slope and dip towards the plane of the slope. Two arrangements are considered: Plane failure The aim of the investigation is to determine the influence of the main … and rock strengths are the factors controlling failure through the rock mass. The analysis technique chosen depends on both site In rock slopes the potential failure bodies are usually (but not necessarily) bounded by discontinuities i.e. The wedge failure phe-nomena in a rock slope. If sliding distance of rock block or rock mass that detached by sliding, toppling, or falling was negligible to descending distance through air, it is dened as (2016) A method for assessing discontinuity poles for potential wedge sliding. The studied mechanism consists of a discrete block that is separated from the rock mass by a tension crack filled with a wedge block or rock fragments. Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. There are several tools of increasing complexity that can be used to facilitate a limit equilibrium analysis of rock slopes. 0 0000024197 00000 n (20 marks) (d) Using the planar failure mode equation, calculate the required anchor bars to stabilize the entire rock slope to factor of safety 2. The failure surface is ill-defined in flow slides. Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes (e.g. 0000001244 00000 n It is also known as block failure or plane failure. While performing kinematic analysis for wedge failure of rock slope in Dips 6.0 software (RocScience), it indicates region of secondary wedge failure envelop (marked by yellow by default). Stability Analysis of Rock Slopes for Plane and Wedge Failure A simple formula for plane slope failure is derived, which may be used for the design of anchors to ensure the safety of rock masses endangered by slides. Overall stability is usually controlled by rock mass strength and structure, especially in large open pits. Fourth Geo-China International Conference. startxref (1972) A useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected. Because the rock mass behavior is significantly governed by the presence of joints or other discontinuities, several types of slope failure, such as plane failure, wedge failure, toppling failure, buckling failure and circular failure, are often observed. From a rock slope design perspective, the most important characteristic of a discontinuity is its (a) Wedge failure on two Planar failure in rock in which a intersecting discontinuities with discontinuity 'daylights" the a line of intersection which slope face and/or the ... failure modes (planar, wedge, toppling, etc. 0000001488 00000 n 0000002658 00000 n The results of the stereographic projection show that wedge, plane and toppling Types of slope/ground failure 2 Planar failure 3 Wedge failure 4 Toppling failure 5 Circular failure 6 3 Controls for ground failure 7 Catch bunds 8 Exclusion zones 9 4 Design of benches and faces 10 ... is weak rock, bedding, joints, structures, blast damage, vehicle vibrations, DUNCAN C. WYLLIE A wedge failure in a rock slope 21 m (70 ft) high was stabilized by unloading the top third of the failure, constructing a concrete wall to reinforce the … Types of Slope Failure. 0000001383 00000 n Flow slides can occur in dry and wet soils. This type of failure occurs when there are fissures, joints, or weak soil layers in slope, or when a slope is made of two different materials. Toppling failure is one of the most common modes of failure of rock slopes in layered rock strata. Rock slopes form part of the components in many highway or roadway constructions in hilly terrain. Imp Coll Sci Technol Rock Mech Res Rep 19: 1-10. The design of such slopes can sometimes be based upon an analysis of simple wedge failure. Natural events include failure due to flash flood, excessive seepage, pore pressure, seismic event, presence of weak discontinuities across the rock slope, shear zones, toe cutting of slope by meandering river leading to unstable slope due to change in slope geometry. Calculated factor of safety = 0.4. SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes (e.g. ���.�9�rWȅ̦�@�s-��q��(E�P��� E�ä�g��A�10it`� 820�i~ V�(1�1ȰM. Wedge failure The slope failure occurred along the plane of the soil mass is known as wedge failure. Wedge Failure Wedge failure, also known as block failure or plane failure, generates a failure plane that is inclined. The paper i ntroduces a series of guidelines for interpretation of the results of rock slopes. 0000000016 00000 n 0000005569 00000 n Circular failure generally is observed in slope of soil, mine dump, weak rock and highly jointed rock mass. The results indicated the potential for both planar … The wedge failure analysis is based on satisfying the equilibrium conditions of the wedge. This paper presents the results of the slope failure analyses from fracture distributions and their relation to tectonic activity; the analytical results have indicated that the phenomena of plane failure, wedge failure and toppling failure can occur at almost of the survey sites within the study area. 2nd Quarter 2005 C over Story Figure 3. An extract from Stability Analysis of Rock Slopes for Plane & Wedge Failure with the Aid of a programmable Pocket Calculator, K. Kovari and P. Fritz, Federal Institute of Technology Zurich, Switzerland Institute of Highways and Underground Structures, Department of Rock Mechanics, 10 pgs. " While performing kinematic analysis for wedge failure of rock slope in Dips 6.0 software (RocScience), it indicates region of secondary wedge failure envelop (marked by yellow by default). PDF | On Jun 20, 2008, Mohamed Fadlelmula and others published Reliability-Based Modeling of Wedge Failure in Rock Slopes | Find, read and cite all the research you need on ResearchGate Although, field observations may provide valuable clues the about scales discontinuities exert greater influence on behaviour than do intact rock properties. In rock slopes plane, wedge, toppling and rock fall are common modes of failures (Tang et al., 2016, Lee and Wang, 2011, Yoon et al., 2002, Hoek and Bray, 1981, Hocking, 1976). 4. This paper presents an alternative approach using closed-form equations, for cases where the upper ground surface dips in the same direction as the slope face. Slope stability in mining and civil engineering projects is always a problem of great concern. Daylighting sheet joint with large perched block in grade III zone or granite rock slope 23 to contend with different geological features or instability problems. The present work focuses on the study of the wedge failure, which occurs as sliding of a mass of rock on two intersecting planes, generally discontinuity planes. This type of failure occurs when there are fissures, joints, or weak soil layers in slope, or when a slope is made of two different materials. Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. 5.1 Introduction . Wedge Failure Wedge failure can occur in rock mass with two or more sets of discontinuities whose lines of intersection are approximately perpendicular to the strike of the slope and dip towards the plane of the slope. Slope stability analysis is a static or dynamic, analytical or empirical method to evaluate the stability of earth and rock-fill dams, embankments, excavated slopes, and natural slopes in soil and rock. Failure of a rock slope on one or two plane surfaces is the simplest but at the same time the most important type of sliding failure and forms the basis for the stability analysis of rock slopes. The limiting equilibrium methods for slopes under various conditions against wedge failure have been previously proposed by several investigators. The proposed techniques arguably result in an improved level of confidence in the design of rock slopes susceptible to wedge failure. Introduction. The aim of the investigation is to determine the influence of the main … ¶The stability of slopes during and after excavation is always of great concern in the field of rock engineering. Translational slides in rock masses are dependent upon the spatial arrangement of the discontinuities within the mass and their relationship to the geometry of the slope. If sliding distance of rock block or rock mass that detached by sliding, toppling, or falling was 1). Slope failures depend on the soil type, soil stratification, groundwater, seepage, and the slope geometry. The wedge failure is quite similar to a translational failure. Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. 4). 0000004993 00000 n C. Wedge failure factor of safety analysis. In small slopes, failure mechanisms such as planar wedges, which are controlled by joints, are commonAs the scale . Failure of a slope along a weak zone of soil is called a translational slide (Figure 16.2a). The required criteria for wedge failure … Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. of Colombia, Carrera 30 No. trailer Abstract: The failure mechanisms of hard rock slopes are usually dominated by the joint and fault system of the rock mass, the properties of which show an inherent spread. Because the potential failure was located above a major railroad line, it was necessary to carry out this work with minimal interruption of traffic. Basic Geometry of a Surface and a Rock Face 3D geometry of the evaluated rock slope (terrain) and excavation pit (rock face) is to be set up in a frame named “Geometry“. ABSTRACT This paper presents the wedge failure analysis at different pier locations for a railway bridge proposed at about 350 m above the ground level, crossing a river and connecting two huge rock slopes in Himalayas, India. Translational slip in rock slopes. of wedge failure is evident. Because the rock mass behavior is significantly governed by the presence of joints or other discontinuities, several types of slope failure, such as plane failure, wedge failure, toppling failure, buckling failure and circular failure, are often observed. joints, foliation surfaces, bedding planes or faults. Static and seismic slope stability analysis confirmed the global stability of the slope. Thus, the stability assessment method has to be capable of coping with this uncertainty. of Civil and Agricultural Engineering, National Univ. A tetrahedral wedge may be formed by two intersecting discontinu- identify the relevant failure modes based on information of wedge geometry and forces acting on the wedge. Section Name: Rock Mechanics (CED 48) Designator of Legally Binding Document: IS 14448 Title of Legally Binding Document: Code of practice for reinforcement of rock slopes with plane wedge failure Number of Amendments: 1 Equivalence: Superceding: Superceded by: LEGALLY BINDING DOCUMENT Step Out From the Old to the New--Jawaharlal Nehru Figure 1-1: A wedge model in ROCPLANE. and/or the equilibrium conditions of natural slopes. Ph.D. Student, Dept. Plane mode of failure generally occurs in slope formed by stratified sedimentary and meta-sedimentary rock formations. 0000005198 00000 n Unlike translational, wedge failure can occur in both finite and infinite slopes. sliding failure in rock slopes. Overall stability is always checked for the possibility of deep-seated failure through the rock mass and the method of slices is usually the tool of choice. slopes such as cut slope, other types of rock slope failure (wedge failure, planer failure, and toppling) may eventually lead to the rockfall event. 1(b)]. 0000038963 00000 n Contrasting features of the different rock The key question with regard to rock slopes along highways is their long-term stability since failure of a rock slope can have serious consequences. The stability of the rock wedge is controlled by: joint sets dip and dip direction, slope geometry and direction, external forces (including water pressure and earthquake) and rock and joints mechanical properties. The toe of the cut was within 6 m (20 ft) of the railway, so even a minor slope failure could reach the track. It is more similar to translational failure but the difference is that translational failure only occurs in case of infinite slopes but wedge failure can occur in both infinite and finite slopes. failure, buckling failure and circular failure, are often observed. The main assumptions in a planar wedge analysis such as ROCPLANE… open pit mining, road cuts, etc.) The analysis and design of rock slopes susceptible to wedge failure is of interest to both civil and mining engineering. Failure of rock or soil slopes takes place due to natural or artificial means. A thermally induced wedging–ratcheting mechanism for slope stability is investigated using a large-scale physical model and using a three-dimensional version of the numerical Distinct Element Method (3DEC). (10 marks) (c) Calculate the factor of safety for wedge failure mode using the formula in Figure Q1(e) when the rock slope is in wet conditions (the student must demonstrate its calculation). This mode of failure needs the dip angle of at least one joint intersection to be greater than the angle of friction of the joint surface. Plane failure; Wedge failure. A planar wedge can be defined by: • a sliding plane • the slope face • the upper ground surface • an optional tension crack as shown in the following figure. Slope stability in mining and civil engineering projects is always a problem of great concern. CHAPTER 5.0: CIRCULAR FAILURE ANALYSIS . For rock slopes usually two free surfaces (lower outcrop and upper outcrop) are present, figure 2. Block or Wedge Slide. 0000005398 00000 n of Colombia, Carrera 30 No. E-mail: © 2016 American Society of Civil Engineers, Estimation of the Lower and Upper Probabilities of Failure Using Random Sets and Subset Simulation, Vulnerability, Uncertainty, and Risk: Quantification, Mitigation, and Management, Stochastic Response Surfaces, Interval Analysis, and the Reliability of Structures, Comparison of Slope Reliability Methods of Analysis, GeoFlorida 2010: Advances in Analysis, Modeling & Design, A Random Field Approach to Reliability Analysis With Random and Interval Variables, ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part B: Mechanical Engineering, https://doi.org/10.1061/9780784480007.002, © 1996–2021, American Society of Civil Engineers. 1. 0000008177 00000 n A wedge failure in a rock slope 21 m (70 ft) high was stabilized by unloading the top third of the failure, constructing a concrete wall to reinforce the toe, and installing tensioned rock anchors. wedge size distributions. 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