Ktisis at Cyprus University of Technologyhttp://ktisis.cut.ac.cyThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Wed, 19 Sep 2018 06:15:04 GMT2018-09-19T06:15:04Z50221An analytical solution in probabilistic rock slope stability assessment based on random fieldshttp://ktisis.cut.ac.cy/handle/10488/4918Title: An analytical solution in probabilistic rock slope stability assessment based on random fields
Authors: Gravanis, Elias; Pantelidis, Lysandros; Griffiths, D. V.
Abstract: An analytical solution for calculating the probability of failure of rock slopes against planar sliding is proposed. The method in based on the theory of random fields accounting for the influence of spatial variability on slope reliability. In this framework, both the cohesion and friction coefficient along a discontinuity are treated as Gaussian random fields which are fully described by their mean values View the MathML source, standard deviations View the MathML source, spatial correlation lengths View the MathML source, and the parameters View the MathML source which account for the cross-correlation between cohesion and coefficient of friction. As shown by the examples presented herein, the spatial correlation of shear strength can have an important influence on slope performance expressed by the probability of failure. This is a significant observation, since ignoring the influence of spatial correlation in design may lead to unconservative estimations of slope reliability.
Wed, 01 Oct 2014 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49182014-10-01T00:00:00ZIntegrating Eurocode 7 (load and resistance factor design) using nonconventional factoring strategies in slope stability analysishttp://ktisis.cut.ac.cy/handle/10488/4919Title: Integrating Eurocode 7 (load and resistance factor design) using nonconventional factoring strategies in slope stability analysis
Authors: Pantelidis, Lysandros; Griffiths, D.V.
Abstract: In traditional allowable stress design, as known, the safety factor is calculated with respect to shear strength of soil(s) by
dividing the available shear strength by the mobilized stresses. The limit-state method, on the other hand, compares — in the form
of the inequality Ed ≤ Rd— the effects of all the actions, Ed, with the corresponding resistance of the ground, Rd. Although this method
considers different loading conditions by using suitable combinations of design values, it is still based on direct comparison of the
available shear strength with the mobilized stresses. In the present paper, various factoring strategies (in addition to the traditional
one with respect to shear strength of soils) are integrated into a limit-state method framework. Eurocode 7 has been chosen for this
purpose. The whole procedure aims at giving a more comprehensive insight into the design of slopes and the sensitivity of safety level
of slopes to the various parameters. In addition, the proposed methodology, as shown, may result in a safety level of slopes signifi-
cantly lower than the respective one obtained using the limit-state method in its traditional form. As man-made slopes that conform
to design standards often fail in practice, even though conservative input values are used, these failures must be treated with more
skepticism by practitioners adopting supplementary design practices such the one presented herein.
Sat, 01 Feb 2014 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49192014-02-01T00:00:00ZStability of earth slopes. Part I: Two-dimensional analysis in closed-formhttp://ktisis.cut.ac.cy/handle/10488/7681Title: Stability of earth slopes. Part I: Two-dimensional analysis in closed-form
Authors: Pantelidis, Lysandros; Griffiths, D.V.; Pantelidis, Lysandros; Griffiths, D.V.
Abstract: A closed-form solution (CFS) satisfying both equilibrium of moments and forces for the stability analysis of earth slopes in 2D is proposed. The sliding surface is assumed circular and treated as a rigid body, allowing the internal state of stress to be ignored. The proposed solution can be applied to both homogenous and non-homogenous slopes of either simple or complex geometry, and can also deal with any kind of additional loading. The method is based on the fact that, all possible forces acting on the slope can be projected onto the failure surface where they are broken into driving and resisting ones. Comparison of the safety factors obtained by the proposed CFS and those obtained by traditional limit equilibrium methods, as applied to several test examples, indicates that the proposed method is more conservative, whereas moreover, it gives a more realistic point of view for the formation of tension crack in slopes.
Sun, 01 Jan 2012 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/76812012-01-01T00:00:00ZDesigning passive rockfall measures based on computer simulation and field experience to enhance highway safetyhttp://ktisis.cut.ac.cy/handle/10488/7752Title: Designing passive rockfall measures based on computer simulation and field experience to enhance highway safety
Authors: Pantelidis, Lysandros; Kokkalis, Alexandros G.; Pantelidis, Lysandros; Kokkalis, Alexandros G.
Sat, 01 Jan 2011 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/77522011-01-01T00:00:00ZFooting on the crest of slope: slope stability or bearing capacity?http://ktisis.cut.ac.cy/handle/10488/4932Title: Footing on the crest of slope: slope stability or bearing capacity?
Authors: Pantelidis, Lysandros; Griffiths, D.V.
Abstract: A footing on the crest of a slope may be considered as either a slope stability or a bearing
capacity problem. Traditional slope stability analysis delivers the safety factor with respect to
shear strength, while traditional bearing capacity analysis delivers the safety factor with
respect to loading. These two strategies indicate quite different safety levels, even when
applied to the same problem. Eurocode 7 (EC7) allows for the use of both strategies. Indeed, in
the limit state framework of EC7 slope stability and bearing capacity problems do not share
the same partial factors. Since, EC7 does not have a special provision for the problem of a
footing on the crest of slope, the question whether it is a bearing capacity or a slope stability
problem remains. The parametric studies presented in this paper based on EC7 design
guidelines and different factoring strategies, shows that the kind of failure mechanism
observed strongly depends on the magnitude and position of the footing loading.
Thu, 01 Jan 2015 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49322015-01-01T00:00:00ZInfluence of spatial variability on rock slope reliability using 1-D random fieldshttp://ktisis.cut.ac.cy/handle/10488/4931Title: Influence of spatial variability on rock slope reliability using 1-D random fields
Authors: Pantelidis, Lysandros; Gravanis, Elias; Griffiths, D.V.
Abstract: In this work, the theory of random fields is used to account for the influence of spatial
variability on slope reliability. Within this framework the friction coefficient along a
discontinuity is treated as a Gaussian random field which is fully described by its mean value,
standard deviation and spatial correlation length. The random field is simulated using the
Local Average Subdivision (LAS) method. As shown by the examples presented herein, the
spatial correlation of shear strength along a failure plane can have an important influence on
slope performance, as expressed by the failure probability. This is a significant observation
since ignoring the influence of spatial correlation in design may lead to non-conservative
estimations of slope reliability. The planar mode of failure is considered.
Thu, 01 Jan 2015 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49312015-01-01T00:00:00ZEqual-area projection: spheroid to sphere to planehttp://ktisis.cut.ac.cy/handle/10488/4920Title: Equal-area projection: spheroid to sphere to plane
Authors: Pantelidis, Lysandros
Abstract: An accurate method for the equal-area projection from spheroid to plane is proposed.
The points of interest are first projected from the spheroid to an equivalent sphere,
that is, to a sphere of equal area. Then, the points of the equivalent sphere are projected
onto the surface of a circumscribing cylinder (cylindrical equal-area projection) following
the standard mapping procedure of mapping the sphere to the plane.
Tue, 01 Jan 2013 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49202013-01-01T00:00:00ZAn innovative landslide risk assessment system: application to highway embankmentshttp://ktisis.cut.ac.cy/handle/10488/4933Title: An innovative landslide risk assessment system: application to highway embankments
Authors: Pantelidis, Lysandros
Abstract: In this paper a landslide risk assessment system referring to highway embankments is proposed. The system in question consists of three stages, a) the quantitative attribution of the failure hazard of embankments, b) the calculation of geometric characteristics of a possible failure and c) the quantitative attribution of consequences. As regards to the first stage, the failure hazard derives from the drained condition of embankments and the influence that climatic conditions have on their stability; the latter being the most common landslide-triggering factor. The second stage is based on existing methods and models; allowing for application in Highway Engineering the proposed system provides an assessment of the failure extent with regard to roadway elements. Finally, the third stage fully distinguishes the consequences to traveler's safety from those to traffic flow. Correspondingly, there are two risk values, where, the highest one is chosen every time. Based on the last, an alertness condition is assigned accompanied by recommended actions.
Sat, 01 Jan 2011 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49332011-01-01T00:00:00ZStability Assessment of Slopes Using Different Factoring Strategieshttp://ktisis.cut.ac.cy/handle/10488/3624Title: Stability Assessment of Slopes Using Different Factoring Strategies
Authors: Pantelidis, Lysandros; Griffiths, D.V.; Pantelidis, Lysandros
Abstract: Traditional slope stability analysis delivers the factor of safety with respect to shear strength, which is the factor by which tan phi' and c' must be reduced to bring a slope to the point of failure. In the present paper, alternative strategies are considered to include the factors by which destabilizing parameters, such as pore pressures and gravitational loads, must be increased to bring a slope to the point of failure. The approach described gives a more comprehensive insight into the stability of slopes and the sensitivity of failure to different input parameters. Finally, the practical use of the alternative factoring strategies is illustrated through two application examples referring to a slope under different loading combinations ( pore-pressure ratio and horizontal seismic coefficient).
Description: The writers wish to acknowledge the support of NSF Grant No. CMMI-0970122 on GOALI: Probabilistic Geomechanical Analysis in the Exploitation of Unconventional Resources for this research carried out at the Colorado School of Mines. The support of KGHM Cuprum, Wroclaw, Poland through the Framework 7 EU project on Industrial Risk Reduction is also recognized.
Sun, 01 Jan 2012 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/36242012-01-01T00:00:00ZStability of earth slopes. Part II: Three dimensional analysis in closed-formhttp://ktisis.cut.ac.cy/handle/10488/7680Title: Stability of earth slopes. Part II: Three dimensional analysis in closed-form
Authors: Pantelidis, Lysandros; Griffiths, D.V.; Pantelidis, Lysandros; Griffiths, D.V.
Abstract: A closed-form stability analysis of earth slopes performed in 3D is proposed. The sliding surface is assumed spherical and treated as a rigid body allowing the internal state of stress to be ignored. The proposed closed-formed solution (CFS) can be applied to both homogenous and non-homogenous slopes of either simple or complex geometry and can also deal with any kind of additional loading. Although it is recognized that the critical failure surface is often non-spherical, the CFS methodology for spheres described herein provides an objective tool for the evaluation of the assumptions made by other limit equilibrium methods including the role of intercolumn forces.
Sun, 01 Jan 2012 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/76802012-01-01T00:00:00ZStability of highway embankments constructed on sloping ground against translational failurehttp://ktisis.cut.ac.cy/handle/10488/4971Title: Stability of highway embankments constructed on sloping ground against translational failure
Authors: Pantelidis, Lysandros
Abstract: A translational failure of a highway embankment constructed on sloping ground may occur either in the mode of overall instability or in the mode of local instability. The stability analysis of the first mode is based on the assumption that the whole cross-section of the embankment will slide along the inclined base surface, whilst the second mode is based on the assumption of Rankine's active state of stress. In this paper the determination of the prevalent mode of failure – overall or local – is provided via a chart derived from force polygon analysis, with the dimensionless parameter, c′/γH, and the effective friction angle, φ′, as its axes. Furthermore, the determination of the most probable failure plane in the cross-section of the embankment is attempted and additionally the role of the cohesion in the stability is discussed. Finally, an estimation of the amplitude of failure at the road surface in the case of local instability is given. A confirmation of the aforementioned was achieved through case studies of highway embankments that have failed as a consequence of water infiltration and the development of high pore water pressures. A comparison between the local and the respective overall instability safety factor is given.
Tue, 01 Jan 2008 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49712008-01-01T00:00:00ZStability against translational failure of non-cohesive embankments founded on natural slopeshttp://ktisis.cut.ac.cy/handle/10488/4945Title: Stability against translational failure of non-cohesive embankments founded on natural slopes
Authors: Pantelidis, Lysandros
Abstract: A translational failure of a road sidehill fill may occur either in the form of overall instability or in the form of local instability of slope toe. The stability analysis of the first form is based on the assumption that the whole cross-section of the fill will slide along the inclined base, whilst the second form on the assumption of an active Rankine state in the region of the slope toe. In this paper three well documented case studies of road sidehill fills that have failed locally are presented. The failures occurred as a consequence of development of excessive pore water pressures. The way in which the pluvial water affected the stability of fills is described. Furthermore, the safety factor is provided for both cases of local and overall instability, whilst, a discussion upon the location of the Rankine’s failure plane inside the fills is attempted.
Tue, 01 Jan 2008 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49452008-01-01T00:00:00ZDetermination of soil strength characteristics performing the plate bearing testhttp://ktisis.cut.ac.cy/handle/10488/4947Title: Determination of soil strength characteristics performing the plate bearing test
Authors: Pantelidis, Lysandros
Abstract: In the international literature there is often confusion between the
terms Modulus of Elasticity EYoung and Modulus of Deformation EDef for homogenous, isotropic
masses, which, sometimes, plainly referred as Modulus E, without any further explanation.
In this paper a distinction between the EYoung and the EDef is being done and the interest
is concentrated in the Plate Bearing Test, which is commonly used in highway earthworks.
Moreover, a soil classification diagram is given, in which the soils are classified by
their shear strength parameters and their behavior, as totally elastic or elastoplastic, under
specific loading applied by rigid circular plate. Finally, a method for the estimation of the
soil parameters is proposed, using only the in-situ Plate Bearing Test. The study and the
documentation were supported by a presentation of theoretical examples, based on the Finite
Element Method.
Sat, 01 Jan 2005 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49472005-01-01T00:00:00ZRock catchment area design chartshttp://ktisis.cut.ac.cy/handle/10488/4944Title: Rock catchment area design charts
Authors: Pantelidis, Lysandros
Abstract: Studies on the effectiveness of deep ditches against rockfalls have shown that, the original Ritchie (1963) guidelines are not as conservative as previously thought. Moreover, following these guidelines, a unique ditch "depth - width" pair of values is obtained for a given rock cutting not allowing for the chosen of the most economical solution. The above findings gave rise to the research presented herein, where, a number of design charts based on a computer simulation program (RocFallTM) are proposed for deep rockfall ditches. Rockfall concrete walls and fences became also subject of research as there are no relevant design charts currently available. The assumptions made for the derivation of the proposed charts are: a) the number of falling rocks is one hundred, b) the rocks are detached from the slope crest, c) the initial speed of falling rocks is zero, d) the material of slope is a clean hard bedrock and e) the base of the catchment area is covered by a layer of gravel to absorb the energy of falling rocks. For the case of deep rockfall ditches it was additionally assumed that, the ditch foreslope adjacent to the roadway is vegetated. Furthermore, as a cut slope can be of any rock type and thus, charts of this category provide indicative dimensions, the RocFallTM default material settings (e.g. coefficient of restitution) were adopted. Finally, it is noted that, for the simple geometries studied using RocFallTM (slopes without outcrops and benches) the rock impact distance was always zero and therefore, the calculated catchment area width should be corrected adding the maximum impact distance of rocks obtained by Pierson et al. (2001) empirical study.
Fri, 01 Jan 2010 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49442010-01-01T00:00:00ZRock failure risk assessment in highway maintenance managementhttp://ktisis.cut.ac.cy/handle/10488/4946Title: Rock failure risk assessment in highway maintenance management
Authors: Mouratidis, Anastasios; Pantelidis, Lysandros
Mon, 01 Jan 2007 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49462007-01-01T00:00:00ZAn alternative rock mass classification system for rock slopeshttp://ktisis.cut.ac.cy/handle/10488/4927Title: An alternative rock mass classification system for rock slopes
Authors: Pantelidis, Lysandros
Abstract: A system for the quantification of the failure hazard of rock cuttings structured in the form of rating tables is proposed. Rock cuttings are classified according to their failure hazard taking into account both their drained condition and the influence that climatic conditions have on stability; the latter being the most common landslide-triggering factor. The system deals with seven types of failure including slides, topples and falls. Where possible and convenient, parameters are amalgamated using well-established expressions of safety factor increasing the objectivity of the system. In addition to triggering mechanisms, site-specific parameters related to the mean and critical precipitation height, as well as the potential for the development of adverse, water-related conditions are taken into account to arrive at a Hazard Index value.
Mon, 01 Feb 2010 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49272010-02-01T00:00:00ZRock slope stability assessment through rock mass classification systemshttp://ktisis.cut.ac.cy/handle/10488/4928Title: Rock slope stability assessment through rock mass classification systems
Authors: Pantelidis, Lysandros
Abstract: Over the last several decades, rock mass classification systems have been proposed in order that cuttings at high risk for failure be identified, and preventive measures be effectively prioritized. The present paper attempts a review of the systems in question, illustrating the main differences and similarities among them, which are focused on the types of failures considered and the factors involved. The reliability of these systems is discussed as well. Relatively, these systems contain factors which raise queries about their suitability or the manner by which they are attributed into them. Moreover, although a rock cut failure event presupposes the action of a triggering factor (e.g., earthquake, precipitation), rock mass classification systems, by omitting it, do not classify cuttings according to their actual hazard (potentiality) for failure. Groundwater, when it is not erroneously ignored, is taken into account as instability factor with limited effect upon the systems (<15%) and not as a triggering factor for failure. Additionally, a number of suggestions regarding rock mass classification systems are given. Relatively, it is recommended rock cuttings to be classified according to their failure hazard taking into account both their condition and the influence of triggering factors upon stability. Moreover, each type of failure should be examined independently, as each one of them is governed by specific instability factors. Finally, some recommendations concerning amalgamation of factors, the possible ways that water may trigger a failure and the quantification of the most common triggering factors for failure (earthquake and precipitation) are provided.
Thu, 01 Jan 2009 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49282009-01-01T00:00:00ZDetermining of the soil strength characteristics through the plate bearing testhttp://ktisis.cut.ac.cy/handle/10488/4929Title: Determining of the soil strength characteristics through the plate bearing test
Authors: Pantelidis, Lysandros
Abstract: In the international literature there is often a confusion between the terms
Modulus of Elasticity, EYoung, and Modulus of Deformation, EDef which is sometimes
plainly referred to as Modulus E. In this paper the definitions of both the EYoung and the
EDef have been clarified. Moreover, a soil classification diagram has been derived based
on numerical analysis through a finite element software where soils are classified
according to their shear strength parameters (c, φ) and their behavior under loads
generated using a rigid circular bearing plate. Finally, a method for the determination of
shear strength parameters, as well as the EYoung of soils has been proposed using the insitu
Plate Bearing Test and solving a 3x3 mathematical system. The study and
documentation of the proposed method is supported through three theoretical examples.
Tue, 01 Jan 2008 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49292008-01-01T00:00:00ZSemi-analytical model for the determination of vertical settlement of crest of road embankments founded on sloping groundhttp://ktisis.cut.ac.cy/handle/10488/4925Title: Semi-analytical model for the determination of vertical settlement of crest of road embankments founded on sloping ground
Authors: Pantelidis, Lysandros
Abstract: Instabilities that follow the pattern of local translational sliding are rather common along old highway embankments founded on natural slopes, mainly in mountainous terrains. In this paper a semi-analytical model for the determination of the vertical settlement of crest of non-cohesive road embankments founded on sloping ground is presented. The model is based on the principal of conservation of energy, where the change of the potential energy of the sliding mass between its initial and final position is taken as equal to the energy dissipated in deformation, that is, in grain to grain friction inside the body of the embankment and along its base. According to the proposed methodology, the vertical settlement Δy of crest results proportionally to the deformation velocity of embankment mass. The mean value of the maximum velocities of embankment grains acquired during sliding is used. The last is obtained from a proposed empirical diagram, the magnitude of which depends on the embankment height, the gradient of natural base and the unit weight and particle size distribution of the embankment material.
Fri, 01 Jan 2010 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49252010-01-01T00:00:00ZA critical review of highway slope instability risk assessment systemshttp://ktisis.cut.ac.cy/handle/10488/4924Title: A critical review of highway slope instability risk assessment systems
Authors: Pantelidis, Lysandros
Abstract: This paper reviews existing highway slope instability risk assessment systems. It demonstrates that both quantitative and qualitative systems have some major disadvantages with a common characteristic being the lack of emphasis on the geology and geomorphology of slopes. Furthermore, the role of climatic conditions (the most common landslide triggering factor) is diminished or even ignored. It is noted that the existing risk assessment systems focus either on only one category of consequences (e.g. travellers’ safety) or simply sum the scores of more than one category, which may lead to an under-estimation of the significance of a consequence category. Finally, the suitability and reliability of the most commonly used consequences factors are discussed.
Sat, 01 Jan 2011 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49242011-01-01T00:00:00ZStability tables for homogeneous earth slopes with bencheshttp://ktisis.cut.ac.cy/handle/10488/4922Title: Stability tables for homogeneous earth slopes with benches
Authors: Pantelidis, Lysandros; Psaltou, Emmanouil
Abstract: Seven decades after the proposal of the first stability charts by Taylor (1937) many things have changed regarding the design and stability analysis of man-made slopes. High earth slopes with complex geometry (e.g. with benches) are often met in modern design practices, the stability analysis of which is based exclusively on relevant software. Despite of the wide use of computers in geotechnical engineering, stability charts and tables have been proved to be very useful in preliminary design and in checking software outcomes. Motivated by the above considerations, stability tables referring to homogeneous earth slopes with benches have been proposed. The tables in question deal with slopes having gradient 1:2, 1:1 or 2:1 (V:H) and 3- or 4-meter wide benches every 8 or 10m of slope height. The influence of groundwater on stability of slopes is also taken into account through the pore pressure ratio. In total, 2592 solutions were carried out using SLIDE™
Fri, 01 Jun 2012 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49222012-06-01T00:00:00ZArea of spherical lune formed by two random planeshttp://ktisis.cut.ac.cy/handle/10488/4921Title: Area of spherical lune formed by two random planes
Authors: Pantelidis, Lysandros
Abstract: An analytical solution for the exact calculation of the area of spherical lune
formed by two random planes intersected in the sphere is given.
Sun, 01 Jan 2012 00:00:00 GMThttp://ktisis.cut.ac.cy/handle/10488/49212012-01-01T00:00:00Z