• Geomechanics and Engineering
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• v.9 no.1
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• pp.115-124
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• 2015

Determination of mobilized shear strength parameters (that identify stresses on the failure plane) is required for analyzing the stability by limit equilibrium method. Generalized Hoek-Brown (GHB) and Mohr-Coulomb (MC) failure criteria are usually used for obtaining stresses on the plane of failure. In the present paper, the applicability of these criteria for determining the stresses on failure plane is investigated. The comparison is based on stresses on the real failure plane which are obtained from the Mohr stress circle. To do so, 18 sets of data (consist of principal stresses and angle of failure plane) presented in the literature are used. In addition, the values account for (VAF) and the root mean square error (RMSE) indices were calculated to check the determination performance of the obtained results. Values of VAF and RMSE for the normal stresses on the failure plane evaluated from MC are 49% and 31.5 where for GHB are 55% and 30.5, respectively. Also, for the shear stresses on failure plane, they are 74% and 36 for MC, 76% and 34.5 for GHB. Results show that the obtained stresses and angles of failure plane for each criterion differ from real ones, but GHB results are closer to the empirical results. Also, it is inferred that results are affected by the failure envelope not real failure plane. Therefore, obtained shear strength parameters are not mobilized. Finally, a multivariable regressed relation is presented for determining the stresses on the failure plane.

• Journal of the Korean Geosynthetics Society
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• v.9 no.3
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• pp.19-27
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• 2010

In this study, a series of triaxial tests to Jeju basalt were carried out and then shear strength parameters of rock were estimated by the Lade's three-dimensional failure criterion. Also, the characteristics of shear strength parameters and failure plane which were estimated by the three-dimensional failure criterion were analyzed and this failure criterion was compared with the Mohr-Coulomb failure criterion. The variables of ${\eta}_1$ and m are derived from the relationship between ($I_1^3/I_3-27$) and ($P_a/I_1$) during the failure period using the Lade's three-dimensional failure criterion. The failure plane size of Tracy-basalt has the largest plane and that of Scoria has the smallest plane among other octahedral planes which is the three-dimensional failure plane. Also, the failure plane of Tracy-basalt is formed as a triangle and that of Scoria is formed as a circle among other octahedral planes. As the result of comparison with the triaxial test results and the Lade's failure envelope and the Mohr-Coulomb failure envelope, the Lade's failure envelope matched up under higher stress, while the Mohr-Coulomb failure envelope matched up under lower stress. Also, the Lade's three-dimensional failure plane is larger than the Mohr-Coulomb three-dimensional failure plane. It means that the shear strength parameters estimated by the Lade's failure criterion is larger than that of the Mohr-Coulomb failure criterion.

• Structural Engineering and Mechanics
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• v.6 no.2
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• pp.143-159
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• 1998

The objective of this present work is to estimate the failure loads, associated maximum transverse displacements, locations and the modes of failure, including the onset of delamination, of thin, square symmetric laminates under the action in-plane positive (+ve) shear load. Two progressive failure analyses, one using the Hashin criterion and the other using a Tensor polynomial criterion, are used in conjunction with finite element method. First order shear deformation theory along with geometric non-linearity in the von Karman sense have been employed. Variation of failure loads and failure characteristics with five type of lay-ups and three types of boundary conditions has been investigated in detail. It is observed that the maximum difference between failure loads predieted by various criteria depends strongly on the laminate lay-up and the flexural boundary restraint. Laminates with clamped edges are found to be more susceptible to failure due to transverse shear (ensuing from the out of plane bending) and delamination, while those with simply supported edges undergo total collapse at a load slightly higher than the fiber failure load. The investigation on negative (-ve) in-plane shear load is in progress and will be communicated as part-II of the present work.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.513-520
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• 2002

The stability analysis of rock slope can be predicted using a suitable field data but it cannot be predicted unless suitable field data was taken. In this study, artificial neural networks theory is applied to predict plane failure that has a few data. It is well known that human brain has the advantage of handling disperse and parallel distributed data efficiently. On the basis of this fact, artificial neural networks theory was developed and has been applied to various fields of science successfully In this study, error back-propagation algorithm that is one of the teaching techniques of artificial neural networks is applied to predict plane failure. In order to verify the applicability of this model, a total of 30 field data results are used. These data are used for training the artificial neural network model and compared between the predicted and the measured. The simulation results show the potentiality of utilizing the neural networks for effective safety factor prediction of plane failure. In conclusion, the well-trained artificial neural network model could be applied to predict the plane failure stability of rock slope.

• The Journal of Engineering Geology
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• v.12 no.3
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• pp.295-303
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• 2002

The stability of rock slopes is closely related to the factors such as: type of rock, development of geological structures, weathering, characteristics of rock, and the shape of the geological features. When we design the rock slope, the slope stability is determined by the discontinuity causing the circular, plane or wedge failure. The failure happens when the slope is under the unstable geological condition. But in some cases, slope failure has occurred even though the slope is under stable geological conditions. In this respect, this paper presents the plane failure conditions for domestic rock slopes through research of sites where slope failure has occurred regardless of whether or not it satisfied the stable geological conditions.

• The Journal of Engineering Geology
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• v.29 no.3
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• pp.315-327
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• 2019

Back analysis has been used to evaluate the factor of safety and circular failure plane at the landfill failure site. However, the estimated circular failure plane by back analysis is quite different from what is observed in the field. Thus, this study was conducted to estimate an actual shear failure plane inside the ground which gives a more accurate failure plane. Cone penetration test (CPT), boring test, soft X-ray image scan, density logging, and ultrasonic logging were conducted at the field and laboratory. The result of CPT showed significantly lower cone resistance, pore pressure, and undrained shear strength at a particular part. This part is a possible shear failure plane inside the ground. To validate, the soft X-ray scan images were analyzed and found the disturbed (inclined) bedding plane induced by shear activity at the estimated shear failure plane. Density and ultrasonic logging tests also found a similar result. Thus, the method in this study is possible to estimate the shear failure plane inside the ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.457-464
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• 2000

Stereographic method is a general and basic method to analyse sliding failure potential of rock slope. Region of failure analysis using stereographic method extend to curved slope from straight slope in this paper, Curved slope is defined as the multi-face slope with free surface more than two face and has different characteristics from straight single face slope. Individual daylight envelopes of free surfaces are combined into total daylight envelope of multi-face slope. So, sliding envelope of multi-face slope is the daylight envelope except friction cone. Specially, If only single joint set is developed in the slope, single plane sliding(or plane failure) is impossible in the single-face straight slope, but possible in the multi-face slope. In the multi-face slope with only one joint set, single plane sliding occurs when orientation of sliding plane is between two side slope orientation in the sliding envelope.

• Geotechnical Engineering
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• v.12 no.6
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• pp.37-50
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• 1996

In this study, we collected data through the investigation of rock slopes of highway. By analyzing the collected data, the main factors of rock slope failure were studied. We studied on the failure types and scales according to rock types and geological structures in many rock slopes of highway. As a result, it was shown that many failed slopes were distributed in the areas of Cretaceous sedimentary rocks of south-eastern part in the Korean Peninsula and the Gneiss Complex in both Kyonggi-Do and Kangwon-Do. According to rock types, the following slope failure types were shown : that igneous rocks had the types of rock fall, plane failure, soil erosion and circular failure but had low failure frequency, and sedimentary rocks had predominantly the type of plane failure. Metamorphic rock showed the types of circular failure, wedge failure and plane failure due to poor rock qualities . According to geological structures, the following slope failure types were shown slope failure in igneous rocks was caused by joints, and in sedimentary rocks by bedding plane, and in metamorphic rocks by faults and poor rock qualities.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.64-73
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• 1996

The three-dimensional strength behavior of compacted decomposed granite soil was studied using cubical triaxial tests with independent control of the three principal stresses. All specimens were loaded under conditions of principal stress direction fixed and aligned with the directions of compacted plane. For comparable test conditions, the major principal strain and volume strain to failure were smallest when the major principal stress acted perpendicular to the compacted plane. The opposite extremes were obtained when the major principal stress acted parallel to the compacted plane. In cubical triaxial tests with same b values and with ${\theta}$ values in one of three sectors of the octahedral plane, independent of the range of ${\theta}$, higher friction angles are obtained in tests with b greater than in triaxial compression tests in which b 0.0, Comparison between the results of the drained cubical triaxial tests on lksan compacted decomposed granite soil and the cross section of the Mohr-Coulomb failure surface as well as the cross section of the Mohr-Coulomb failure surface were made. Lade's isotropic failure criterion based on vertical specimens overestimates the strengths for tests performed with values of 0 between 90˚ and 1 50˚ the Mohr-Coulomb criterion generally underestimates the strengths of tests performed with values of ${\theta}$ between $0^{\circ}$ and $180^{\circ}$ except around the $120^{\circ}$.

• Tunnel and Underground Space
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• v.31 no.5
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• pp.360-373
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• 2021

Many sources of uncertainty exist in geotechnical analysis ranging from the material parameters to the sampling and testing techniques. The conventional deterministic stability analysis of a plane failure in rock slope produce a safety factor but not a probability of failure or reliability index. In the conventional slope stability analysis by evaluating the ground uncertainty as an overall safety factor, it is difficult to evaluate the stability of the realistic rock slope in detail. This paper reviews some established probabilistic analysis techniques, such as the MCS, FOSM, PEM, Taylor Series as applied to plane failure of rock slopes in detail. While the Monte - Carlo methods leads to the most accurate calculation of the probability of safety, this method is too time consuming. Therefore, the simplified probability methods could be alternatives to the MCS. In this study, using these simple probability methods, the failure probability estimation of a plane failure in rock slope is presented.