wedge failure in rock slopes

Overall stability is usually controlled by rock mass strength and structure, especially in large open pits. increases more complex mechanisms such as step-path failuresand rotational shear failure , which The results indicated the potential for both planar … 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. The limiting equilibrium methods for slopes under various conditions against wedge failure have been previously proposed by several investigators. trailer 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 SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in 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. 0000038963 00000 n 1. Failure of a slope along a weak zone of soil is called a translational slide (Figure 16.2a). (1972) A useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected. Figure 2 shows the wedge failure phenomena in a rock slope. 0000001244 00000 n Dilatancy in a rock mass is unconstrained near slopes as normal stress on joints is small due to weight of the wedge. Summary A simple formula for plane slope failure is derived, which may be used for the design of … 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. 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. Imp Coll Sci Technol Rock Mech Res Rep 19: 1-10. The failure surface is ill-defined in flow slides. Wedge failure The slope failure occurred along the plane of the soil mass is known as wedge failure. wedge size distributions. 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. 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. Translational slip in rock slopes. 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 … 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. The movement of the failure body may occur in any several modes: translational sliding, rotational sliding, toppling, falling or a combination of modes. 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. The analysis technique chosen depends on both site Stability Analysis of Rock Slopes with Plane and Wedge Failure by Means of a Pocket Calculator 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. 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, The wedge failure is quite similar to a translational failure. The required criteria for wedge failure … There are several tools of increasing complexity that can be used to facilitate a limit equilibrium analysis of rock slopes. 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. 2nd Quarter 2005 C over Story Figure 3. In this code only one mode that is plane wedge failure ls described (see Fig. Calculated factor of safety = 0.4. 5.1 Introduction . %%EOF ¶The stability of slopes during and after excavation is always of great concern in the field of rock engineering. C. Wedge failure factor of safety analysis. Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. 0000000016 00000 n Wedges are defined by two intersecting discontinuity planes, the slope surface and an optional tension crack. The paper i ntroduces a series of guidelines for interpretation of the results of rock slopes. of Civil and Agricultural Engineering, National Univ. 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. 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). These interact to control the size and the direction of movement of the slope failure. 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. Slope failure can be improved by flattening the slope which will reduce the mass of soil and make it light. Introduction. 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. Block or wedge slides occur when a soil mass is shattered along joints, seams, fissures, and weak zones by forces emanating from adjacent soils. 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. 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 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. (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). Plane failure; Wedge failure. One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. 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. 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� open pit mining, road cuts, etc.) 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. Toppling failure is one of the most common modes of failure of rock slopes in layered rock strata. 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). 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. Static and seismic slope stability analysis confirmed the global stability of the slope. E-mail: Professor, Dept. of Civil and Agricultural Engineering, National Univ. and rock strengths are the factors controlling failure through the rock mass. Stability-charts-for-rock-slopes-based-on-the-Hoek-Brown-failure-criterion and/or the equilibrium conditions of natural slopes. Among these mechanisms, the wedge failure is one of the most common ways of failure in rock slopes. identify the relevant failure modes based on information of wedge geometry and forces acting on the wedge. 45-03 Building 406 Of 402. The lower surface could have high slope while the upper outcrop surface can be a horizontal surface or a surface with low slope angle. Contrasting features of the different rock The proposed techniques arguably result in an improved level of confidence in the design of rock slopes susceptible to wedge 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). Markland JT. <]>> The site is located in a highly active seismic zone. Because the potential failure was located above a major railroad line, it was necessary to carry out this work with minimal interruption of traffic. Slope stability in mining and civil engineering projects is always a problem of great concern. ROCK SLOPES MODELING Location of the stations along the Werka descent is traced by the GPS. (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. 0000005569 00000 n Planar failure … 0000024197 00000 n 0000005398 00000 n 0 joints, foliation surfaces, bedding planes or faults. [22] Smith JV. 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. 93 0 obj <> endobj 93 18 Ph.D. Student, Dept. In rock slopes the potential failure bodies are usually (but not necessarily) bounded by discontinuities i.e. ��.�9�rWȅ̦�@�s-��q��(E�P�� E�ä�g��A�10it`� 820�i~ V�(1�1ȰM. 0000008177 00000 n Wedge Failure Wedge failure, also known as block failure or plane failure, generates a failure plane that is inclined. Two arrangements are considered: Plane failure IS 14448 (1997): Code of practice for reinforcement of rock slopes with plane wedge failure 4). 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. 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 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. 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 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. 0000001383 00000 n The rock type was a very competent, massive granite One of the structurally controlled modes of failure in jointed rock slopes is wedge failure. startxref Figure 1-1: A wedge model in ROCPLANE. 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. 0000002658 00000 n The stability of jointed rock slopes under different persistence and various water pressure conditions has been studied. 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. 0000005198 00000 n It is very important to identify the position of most critical circle in analysis of such failure. 1. 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 … and/or the ... failure modes (planar, wedge, toppling, etc. The design of such slopes can sometimes be based upon an analysis of simple wedge 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. Circular failure generally is observed in slope of soil, mine dump, weak rock and highly jointed rock mass. 110 0 obj<>stream Flow slides can occur in dry and wet soils. The wedge failure had developed in a rock cut 21 m ( 7 O ft) high that had a face angle of 7 5 °. KEYWORDS of Colombia, Carrera 30 No. 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“. 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. Slope stability in mining and civil engineering projects is always a problem of great concern. 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. Improvement of slope failure. SWedge is a quick, interactive and simple-to-use analysis tool for evaluating the geometry and stability of surface wedges in rock slopes. Wedge Failure This kind of failure causes a rock mass to slide along two intersecting discontinuities. Block or Wedge Slide. Unlike translational, wedge failure can occur in both finite and infinite slopes. %PDF-1.3 %�� Plane mode of failure generally occurs in slope formed by stratified sedimentary and meta-sedimentary rock formations. 45-03 Building 406 Of 202. This type of failure is commonly seen in slopes of up to 20 or 30 m high in hard jointed rock masses. 0000003821 00000 n xref For example, failures that involve wedges sliding along the line of intersection of two intersecting faults can be analysed using limit equilibrium models. 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. 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. However, due to the geological origin of rock masses, these inputs are uncertain. 0000001488 00000 n 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 CHAPTER 5.0: CIRCULAR FAILURE ANALYSIS . 0000004993 00000 n Although, field observations may provide valuable clues the about Rock slope stability analyses are routinely performed and directed towards assessing the safe and functional design of excavated slopes (e.g. In all the above 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. The aim of the investigation is to determine the influence of the main … Recently, the factor of safety of rock slopes against the wedge failure … Recently, the factor of safety of rock slopes against the wedge failure has been studied in a number of investigations under static … 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. 0000005876 00000 n failure, buckling failure and circular failure, are often observed. If sliding distance of rock block or rock mass that detached by sliding, toppling, or falling was The main assumptions in a planar wedge analysis such as ROCPLANE… Types of Slope Failure. Eng Geol 202: 55-61 The stability assessment according to block theory on the contrary follows a deterministic procedure. 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