wedge failure in rock 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 … Failure of a slope along a weak zone of soil is called a translational slide (Figure 16.2a). 93 0 obj <> endobj 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. Translational slip in rock slopes. Fourth Geo-China International Conference. 45-03 Building 406 Of 202. One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. E-mail: Professor, Dept. 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. The movement of the failure body may occur in any several modes: translational sliding, rotational sliding, toppling, falling or a combination of modes. ); can analyse factor of safety sensitivity to changes in slope g eometry and material properties; more wedge size distributions. 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. 0000001244 00000 n Planar failure … 1. If sliding distance of rock block or rock mass that detached by sliding, toppling, or falling was The stability of jointed rock slopes under different persistence and various water pressure conditions has been studied. The paper i ntroduces a series of guidelines for interpretation of the results of rock slopes. 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. Slope stability in mining and civil engineering projects is always a problem of great concern. SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. The failure surface is ill-defined in flow slides. The results of the stereographic projection show that wedge, plane and toppling of Civil and Agricultural Engineering, National Univ. Static and seismic slope stability analysis confirmed the global stability of the slope. It is very important to identify the position of most critical circle in analysis of such failure. 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. 0000001110 00000 n 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 lower surface could have high slope while the upper outcrop surface can be a horizontal surface or a surface with low slope angle. sliding failure in rock slopes. 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. 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). Failure of rock or soil slopes takes place due to natural or artificial means. The limiting equilibrium methods for slopes under various conditions against wedge failure have been previously proposed by several investigators. 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. The proposed techniques arguably result in an improved level of confidence in the design of rock slopes susceptible to wedge failure. ¶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. 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. startxref 45-03 Building 406 Of 402. Calculated factor of safety = 0.4. trailer C. Wedge failure factor of safety analysis. A tetrahedral wedge may be formed by two intersecting discontinu- Ph.D. Student, Dept. 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, 0000003821 00000 n %PDF-1.3 %�� Flow slides can occur in dry and wet soils. Improvement of slope failure. 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. Wedge Failure Wedge failure, also known as block failure or plane failure, generates a failure plane that is inclined. These interact to control the size and the direction of movement of the slope failure. 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. Rock slopes form part of the components in many highway or roadway constructions in hilly terrain. 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. (2016) A method for assessing discontinuity poles for potential wedge sliding. The analysis and design of rock slopes susceptible to wedge failure is of interest to both civil and mining engineering. (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. ROCK SLOPES MODELING Location of the stations along the Werka descent is traced by the GPS. 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 110 0 obj<>stream 0000005198 00000 n of wedge failure is evident. 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. failure, buckling failure and circular failure, are often observed. Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes (e.g. Figure 2 shows the wedge failure phenomena in a rock slope. 4. The results indicated the potential for both planar … Overall stability is usually controlled by rock mass strength and structure, especially in large open pits. and/or the equilibrium conditions of natural slopes. Plane failure; Wedge failure. SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. The wedge failure is quite similar to a translational failure. joints, foliation surfaces, bedding planes or faults. 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 Stability Analysis of Rock Slopes with Plane and Wedge Failure by Means of a Pocket Calculator The required criteria for wedge failure … 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. Although, field observations may provide valuable clues the about 0000000656 00000 n Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. 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� There are several tools of increasing complexity that can be used to facilitate a limit equilibrium analysis of rock slopes. Introduction. Types of Slope Failure. The stability assessment according to block theory on the contrary follows a deterministic procedure. It is also known as block failure or plane failure. Stability-charts-for-rock-slopes-based-on-the-Hoek-Brown-failure-criterion 93 18 1. Wedge failure The slope failure occurred along the plane of the soil mass is known as wedge failure. 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. 0000008177 00000 n 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. Recently, the factor of safety of rock slopes against the wedge failure … 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. 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. Among these mechanisms, the wedge failure is one of the most common ways of failure in rock 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. of Colombia, Carrera 30 No. of Civil and Agricultural Engineering, National Univ. The determination of representative values for the analysis is therefore crucial. 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. 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. KEYWORDS 0000001203 00000 n 0000005774 00000 n IS 14448 (1997): Code of practice for reinforcement of rock slopes with plane wedge failure ��.�9�rWȅ̦�@�s-��q��(E�P�� E�ä�g��A�10it`� 820�i~ V�(1�1ȰM. 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. Major wedge failure in granite rock slope. 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). [22] Smith JV. 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. 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