¶The stability of slopes during and after excavation is always of great concern in the field of rock engineering. Stability Analysis of Rock Slopes with Plane and Wedge Failure by Means of a Pocket Calculator SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. If sliding distance of rock block or rock mass that detached by sliding, toppling, or falling was 2nd Quarter 2005 C over Story Figure 3. 0000004993 00000 n A tetrahedral wedge may be formed by two intersecting discontinu- The failure surface is ill-defined in flow slides. The wedge failure had developed in a rock cut 21 m ( 7 O ft) high that had a face angle of 7 5 °. There are several tools of increasing complexity that can be used to facilitate a limit equilibrium analysis of rock slopes. Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. open pit mining, road cuts, etc.) Planar failure … 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 … 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 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. Plane mode of failure generally occurs in slope formed by stratified sedimentary and meta-sedimentary rock formations. identify the relevant failure modes based on information of wedge geometry and forces acting on the wedge. 1). sliding failure in rock slopes. It is very important to identify the position of most critical circle in analysis of such failure. The results of the stereographic projection show that wedge, plane and toppling 5.1 Introduction . 0000024197 00000 n 0000002658 00000 n failure, buckling failure and circular failure, are often observed. Contrasting features of the different rock 93 0 obj <> endobj slopes such as cut slope, other types of rock slope failure (wedge failure, planer failure, and toppling) may eventually lead to the rockfall event. E-mail: Professor, Dept. The wedge failure is quite similar to a translational failure. Fourth Geo-China International Conference. 1. 0000005876 00000 n Slope failure can be improved by flattening the slope which will reduce the mass of soil and make it light. These interact to control the size and the direction of movement of the slope failure. Therefore, the failure of a rock mass occurs partially along joints and partially in non-jointed portions, such as in solid rocks, but in massive rocks, it occurs entirely in solid rocks. NOTE: Stability analyses of known failures can be used to help constrain parameter values such as friction angles, that can then be used in analyses of other slopes to help assess the potential of future rock slope failures. of Colombia, Carrera 30 No. The rock type was a very competent, massive granite %PDF-1.3 %���� The stability of jointed rock slopes under different persistence and various water pressure conditions has been studied. 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 The wedge failure phe-nomena in a rock slope. 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). 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. The required criteria for wedge failure … The limiting equilibrium methods for slopes under various conditions against wedge failure have been previously proposed by several investigators. ROCK SLOPES MODELING Location of the stations along the Werka descent is traced by the GPS. In this code only one mode that is plane wedge failure ls described (see Fig. 4. Summary A simple formula for plane slope failure is derived, which may be used for the design of … Figure 2 shows the wedge failure phenomena in a rock slope. IS 14448 (1997): Code of practice for reinforcement of rock slopes with plane wedge failure 93 18 Translational slip in rock slopes. Flow slides can occur in dry and wet soils. The lower surface could have high slope while the upper outcrop surface can be a horizontal surface or a surface with low slope angle. 0000038963 00000 n SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. In many cases, rock mass slope stability is controlled by discontinuities, which determine the most likely mechanism of failure, depending on joints and slope geometry. However, due to the geological origin of rock masses, these inputs are uncertain. Rock slopes form part of the components in many highway or roadway constructions in hilly terrain. 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. 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. 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 Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. 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. 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. 0 Rock Slope Wedge Failure Typical wedge failure involving sliding on two persistent joints with line of intersection of joints daylighting at toe of rock face, and an upper plane that formed a tension crack. of Civil and Agricultural Engineering, National Univ. 0000001488 00000 n joints, foliation surfaces, bedding planes or faults. The main assumptions in a planar wedge analysis such as ROCPLANE… The required criteria for wedge failure … The stability of a particular rock slope is governed by three main engineering geologic factors, 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. open pit mining, road cuts, etc.) Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. and/or the equilibrium conditions of natural slopes. Major wedge failure in granite rock slope. [22] Smith JV. Static and seismic slope stability analysis confirmed the global stability of the slope. Figure 1-1: A wedge model in ROCPLANE. Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes (e.g. 0000005774 00000 n 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 aim of the investigation is to determine the influence of the main … 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. Plane failure; Wedge failure. 0000001383 00000 n 0000000656 00000 n The limiting equilibrium methods for slopes under various conditions against wedge failure have been previously proposed by several investigators. increases more complex mechanisms such as step-path failuresand rotational shear failure , which 0000001110 00000 n 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. 4.2.2 The plane wedge failure occurs under gravity alone when a rock-mass rests on an lnclined geologiml discontlnuity, such as bedding/weakness plane that daylights into the free slope face that is 1-I-ff > WP [see Fig. Block or Wedge Slide. <]>> CHAPTER 5.0: CIRCULAR FAILURE ANALYSIS . 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. of Civil and Agricultural Engineering, National Univ. 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. Random sets arise as a powerful tool to deal with uncertainty, even when limited information of inputs is available. With this framework, this work presents a reliability assessment of wedge stability in rock slopes by random sets, considering the joints geometry and strength parameters as random uncertain variables. 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. 1(b)]. We will introduce a few types of slope failure that are common in soils. 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). 0000000016 00000 n 0000005398 00000 n Block or wedge slides occur when a soil mass is shattered along joints, seams, fissures, and weak zones by forces emanating from adjacent soils. Slope stability in mining and civil engineering projects is always a problem of great concern. 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. International Symposium on Stability of Rock Slopes in Open Pit Mining and Civil Engineering Ian de Bruyn _____ Page 560 Figure 2: 3-D illustration of wedge failure Other modes of failure common in hard rock slopes, such as planar and toppling failure, have not been analysed. 110 0 obj<>stream Failure of a slope along a weak zone of soil is called a translational slide (Figure 16.2a). 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). (1972) A useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected. One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. 0000005569 00000 n 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. of wedge failure is evident. Thus, the stability assessment method has to be capable of coping with this uncertainty. Imp Coll Sci Technol Rock Mech Res Rep 19: 1-10. For rock slopes usually two free surfaces (lower outcrop and upper outcrop) are present, figure 2. Wedge Failure Wedge failure, also known as block failure or plane failure, generates a failure plane that is inclined. For example, failures that involve wedges sliding along the line of intersection of two intersecting faults can be analysed using limit equilibrium models. 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, Improvement of slope failure. 0000003821 00000 n slopes with plane wedge failure [CED 48: Rock Mechanics] IS 14448: 1997 Indian Standard CODEOFPRACTICE FOR REINFORCEMENT OFROCKSLOPES WITH PLANEWEDGEFAILURE ICS 93.020 1997 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 October 1997 Price Group 5 The site is located in a highly active seismic zone. ���.�9�rWȅ̦�@�s-��q��(E�P��� E�ä�g��A�10it`� 820�i~ V�(1�1ȰM. ); can analyse factor of safety sensitivity to changes in slope g eometry and material properties; more 0000001203 00000 n In rock slopes the potential failure bodies are usually (but not necessarily) bounded by discontinuities i.e. In many cases, rock mass slope stability is controlled by discontinuities, which determine the most likely mechanism of failure, depending on joints and slope geometry. trailer One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. 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. 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. 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 … The stability assessment according to block theory on the contrary follows a deterministic procedure. Eng Geol 202: 55-61 The wedge failure analysis is based on satisfying the equilibrium conditions of the wedge. Multiple failure surfaces usually occur and change continuously as flow proceeds. The design of such slopes can sometimes be based upon an analysis of simple wedge failure. of Colombia, Carrera 30 No. The analysis and design of rock slopes susceptible to wedge failure is of interest to both civil and mining engineering. The paper i ntroduces a series of guidelines for interpretation of the results of rock slopes. The movement of the failure body may occur in any several modes: translational sliding, rotational sliding, toppling, falling or a combination of modes. (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. 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. The results indicated the potential for both planar … C. Wedge failure factor of safety analysis. 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. Although, field observations may provide valuable clues the about Failure of rock or soil slopes takes place due to natural or artificial means. 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 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. (2016) A method for assessing discontinuity poles for potential wedge sliding. scales discontinuities exert greater influence on behaviour than do intact rock properties. In all the above 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. 4). Translational Slide. Unlike translational, wedge failure can occur in both finite and infinite slopes. xref Because the potential failure was located above a major railroad line, it was necessary to carry out this work with minimal interruption of traffic. Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. The wedge failure is quite similar to a translational failure. Types of Slope Failure. In many cases, spatially in vertical slopes or very steep slopes such as cut slope, other types of rock slope failure (wedge failure, planer failure, and toppling) may eventually lead to the rockfall event. 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