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The cone-shaped hollow reinforced concrete foundation (CHRF) is an innovative type of mountain wind turbine foundation. Model tests were carried out to investigate the bearing behaviour of CHRFs under monotonic lateral loading. Results show that the lateral bearing capacity of the CHRF increases with the increasing diameter and height of the foundation, whereas it decreases significantly with an increase in loading eccentricity. The CHRF rotates about the rotation centre during loading, and the rotation centre is located at an embedded depth of 0.55–0.65 times the foundation height and is 0.15–0.18 times the diameter of the foundation away from its centreline in the ultimate state. Moreover, the distributions of earth pressures along the sidewall of the CHRF represent that the sidewall of the CHRF in the loading direction is the central part for bearing lateral loads. A formula for estimating the lateral bearing capacity of the CHRF is proposed in terms of the limit equilibrium method and is verified by model test results. It is found that the relative error ranges from 7.99 to 17.2%, and the average relative error is 12.7%, indicating that the theoretical model is applicable to predict the lateral bearing capacity of the CHRF.

Slope toe excavation strongly influences the stress balance of natural slopes and redistributes the stress of the slope body. Consequently, the sliding failure of toe-cut slopes is increasingly becoming more frequent, particularly in regions with persistent rainfall. The effects of external factors, namely, toe excavation and persistent rainfall, which lead to toe-cut slope failure were investigated through the numerical analysis of typical toe-cut slopes in the southeastern coastal region of China. Based on the grey relational theory, sensitivity analysis was carried out on the controlling factors to determine the degree of influence exerted by the external factors on the stability of toe-cut slopes. The stability analysis of toe-cut slopes reinforced by pile-anchor structures under earthquake conditions was carried out using pseudo-static analysis. The safety factor of toe-cut slopes significantly decreases as the excavation height, rainfall duration, and rainfall intensity increase. The slope stability is more sensitive to the excavation height of a toe-cut slope than it is to rainfall. The stability of a toe-cut slope reinforced by a pile-anchor structure was also analyzed under rainfall and earthquake conditions using the limit equilibrium method and pseudo-static analysis, respectively. The slope stability significantly improved when the slope was reinforced by a pile-anchor structure, even when the slope was subjected to persistent rainfall and earthquakes. The findings of this study can provide important guidance for the prevention of geological disasters in mountainous areas.

Although a variety of research works have been carried out to investigate the behavior of nailed slopes and nail walls, only a few studies are devoted to the optimum design of soil nail walls. In this study, the limit equilibrium-based approach presented in FHWA manual, which is the prevalent design method in conjunction with nonlinear programming, has been used. Based on this approach, the optimum nail inclination angle (η) leading to the maximum safety (FS) factor against overall failure was determined for typical soil nail walls. Effects of some primary contributing factors such as nail diameter, nail length, soil friction, slope angle, back slope angle, and layout of nails on the optimum design indices were investigated thoroughly and presented in dimensionless graphs. Results indicate that increase in the nail diameter gives rise to an increase in both FS and ηopt. In addition, increasing the length of nails up to 1.875H leads to the most significant improvement in slope stability. Furthermore, the increase in soil friction results in an improvement in FS and a limited rise in ηopt. Steeper nail walls are less stable and require higher ηopt, a linear function of slope orientation (α). A higher back slope angle was found to reduce FS. Furthermore, it was found that inserting the nails in the lower 1/3 part of the slope leads to the highest efficiency, and the nails have a minor influence on the stability of short walls or highly cohesive slopes.

Bu çalışma kapsamında, Avnik (Bingöl) demir açık ocak işletmesinde meydana gelen şev duraysızlıkları incelenmiştir. Duraysızlıklar, ileri derecede kırıklı çatlaklı fillit ve şist birimlerinde meydana gelmiştir. Limit denge analiz yöntemi ile geri analizler yapılmış ve duraysız şevlerin makaslama dayanım parametreleri belirlenmiştir. Limit denge yöntemi ile makaslama dayanım parametreleri belirlenirken Hoek – Brown yenilme ölçütü kullanılmıştır. Geri analizler neticesine elde edilen GSI değerleri (35 - 32) ile arazi çalışmalarından elde edilen GSI değerleri (41 – 35) birbirleri ile uyumludur. Geri analizler neticesinde fillit ve şist birimleri için Hoek – Brown parametreleri sırası ile mb:0.147, 0.173 s: 3.305e-005, 8.566e-005 a: 0.516, 0.511 olarak hesaplanmıştır., In this study, the slope failures were investigated in Avnik (Bingöl) iron open – pit mine. The slope instabilities occurred in highly weathered phyllite and schist units. The back analyses were carried out considering the limit equilibrium method and the shear strength parameters. While determining shear strength parameters via limit equilibrium method Hoek – Brown failure criterion was used. The GSI values (35 – 32) obtained by back analyses and GSI values (41 – 35) determined by field survey are compatible with each other. Hoek – Brown parameters for phyllite and schist units, which were obtained by back analyses are mb: 0.147, 0.173 s: 3.305e-005, 8.566e-005 a: 0.516 – 0.511, respectively.

The assessment of slope stability factor by a FE analysis using the shear strength reduction method (SRM) enjoys several advantages and owns many shortcomings. As an alternative, a new FE approach ...

The present study provides a discussion on landslide event which occurred along Hill Cart road, in the year 2011. The concerned area, situated in the Tindharia region of West Bengal, is famous as a UNESCO world heritage site and draws tourists owing to the famous toy train operated by the Darjeeling Himalayan Railway. This paper presents a description of the events associated with the catastrophic landslide which resulted in the abrupt halting of the operations of the toy train network and disruption of road traffic. Observations made during the site visit are presented, summarizing the important geological findings. Data collected during the site visit is utilized to identify the probable failure surface. Back analysis is attempted using the limit equilibrium method, to assess the effect of geomechanical parameters on the stability of the slope while replicating the probable range of parameters leading to instability. The results of the back analysis are further utilized in a finite element numerical model to assess the stability of the new slope profile. Measures for improving the stability of the new slope by incorporation of rock bolts are discussed. It is believed that the findings of the present study will be beneficial for future stability analyses at the concerned site.

Conventional earth pressure theories are generally applicable to soils with a linear strength envelope. Preferred granular backfill, however, usually exhibits a decreasing peak friction angle with ...

In this study, an unstable rock slope has been investigated. To evaluate the stability of the pentahedral rock wedge with multi-slip surfaces, an approach based on the limit equilibrium method has been used. The slope has been divided into two parts for the establishment of the model: an upper wedge block and a lower pentahedron block. Namely, a three-dimensional space problem can be resolved into a local equilibrium problem of several sub-blocks. Then, the geometric parameters can be determined, and the mechanical analysis can be carried out. Finally, the minimum safety factor can be calculated by using the optimization method. This proposed approach has been applied to analyze the stability of the unstable rock slope before and after reservoir impoundment. The results show that the safety factor is significantly smaller after reservoir impoundment. The safety factor can meet the safety control standards of specifications without considering the extreme conditions of combined rainstorm and seismic force under the proposed reservoir water level.

Stability charts for slopes remain useful in engineering practice because of their convenience and practicality. This paper presents a new stability chart analysis method based on the Generalized Hoek-Brown (GHB) criterion to rapidly calculate the factor of safety (FOS) of rock slopes. First, critical failure state charts (CFSCs) are produced to represent the relationships among the slope height, unit weight of the rock mass and all the parameters involved in the GHB criterion when the slopes lead to a critical failure state (i.e. FOS = 1.0). Second, based on the CFSCs, the formulas of the FOS derived from mi and dimensionless parameter σcmass/γH are presented for slopes with different slope angles. Thus, the FOS for any slope with a GHB rock mass can be directly determined by taking the GHB parameters (i.e. σc, mi, GSI, and D), the unit weight (γ) and the slope’s geometrical parameters (i.e. height H and slope angle β) as inputs. Finally, 25 cases selected from the published literature are used to illustrate the applicability and validity of the proposed method. The results for these cases show good agreement with those obtained with the limit equilibrium method (LEM).

This study first reviews the numerical manifold method (NMM) which possesses some advantages over the traditional limit equilibrium methods (LEMs) in calculating the factors of safety (Fs) of the slopes. Then, with regard to a trial slip surface (TSS), associated stress fields reproduced by NMM as well as the enhanced limit equilibrium method are combined to compute Fs. In order to search for the potential critical slip surface (CSS), the MAX-MIN ant colony optimization algorithm (MMACOA), one of the best performing algorithms for some optimization problems, is adopted. Procedures to obtain Fs in conjunction with the potential CSS are described. Finally, the proposed numerical model and traditional methods are compared with stability analysis of three typical slopes. The numerical results show that Fs and CSSs of the slopes can be accurately calculated with the proposed model.

Through the research it describes an analytic methodology, which allows to determine the minimum safety factor depending on the depth of tensile crack and the inclination of surface failure on the most critical condition, considering at the same time, surcharge, seismic effect and water pressure. Therefore, it studies the stability of rock slopes considering that the potential of failure surface it is constituted by two blocks with different inclinations. The superior block is limited by a tensile crack that is represented by a fracture without displacement. On the other hand, on the inferior block, geometry is formed by a potential slide plane of α inclination with the horizontal axis, in which are acting shear stresses. Fracture on superior block is characterized by a normal-tensile stresses field that act over the crack whose presence originates when the rock loses its original cohesion. Finally, comparisons are made through examples with the limit equilibrium method and finite elements method, where it determines the safety factor on dry state, water and seism, being all of them too similar. Besides, the methodology compares the track depth and the distance between the intersection point of tensile crack and the edge of the slope face, results shows that the analytic methodology is very conservative and throws the less values of this distances.

This article presents a summary of the research on the novel tortuous surface method to stochastically analyze the stability of two-dimensional bimslopes, which are slopes composed of bimrocks or bimsoils. Tortuous failure surfaces (TFSs) are slip surfaces that develop around blocks when bimslopes fail. The method was automated through an algorithm that locates a slip surface passing around the blocks as if it were the solution of a “maze puzzle.” Slope stability analyses were performed using the limit equilibrium method (LEM). To compare many different models, the normalized factor of safety of a TFS ( $f_{\mathrm {n}}^{\ast }$ ) was computed. $f_{\mathrm {n}}^{\ast }$ is obtained by dividing the fs from the TFS by the fs from the surface potentially produced when there are no blocks (the critical circular surface or the matrix-only surface (MOS)). Two groups of analyses were performed. First, two tortuosity parameters, the tortuous length ratio (TLR) and the average tortuous width (ATW), were analyzed through the evaluation of a hypothetical slope of 10 m height and 35∘ inclination with varying block proportions. Second, similar hypothetical models were developed with three different values of the slope height, slope inclination, and ratio of the unit weight of the blocks to the unit weight of the matrix; then, the behavior of $f_{\mathrm {n}}^{\ast }$ for different values of both the cohesion and friction angle of the matrix was presented in a sensitivity analysis. A prime conclusion of the research is that for prudent geotechnical design, stochastically based stability analyses of bimslopes are far preferable to deterministic analyses.

Nested Newmark model (NNM) can obtain the post-earthquake profile of the slopes in limit equilibrium or limit analysis method. The purpose of this study is to extend the NNM from the limit equilibrium method to a limit analysis method, and then involve the dynamic response of slopes into the prediction of the permanent displacement based on decoupled analysis. Parametric studies are carried out to further investigate the influences of slope height, soil shear wave velocity and input ground motion. The calculated results indicate that neglecting the dynamic response of slopes can underestimate the post-earthquake displacements. As the slope height increases or shear wave velocity reduces, the underestimation is more significant. At the fundamental natural period of the site, the underestimation is particularly remarkable. For induced earthquake waves with a small value of mean period, the influence of the dynamic response can be ignored when the fundamental period deviates from the mean period.

Uncertainties of geotechnical parameters in landslide engineering mainly arise from their spatial variabilities, measuring error and inaccurate constitutive model. Interval limit equilibrium method...

RESUMO: A falha da Barragem de Fundão, o maior desastre de seu tipo no mundo, foi estudada por Morgenstern et al. (2016) através de abordagens bidimensionais. A investigação realizada não apontou mecanismos de instabilidade de taludes como sendo as causas do desastre. No entanto, o formato complexo da face da barragem, com regiões côncavas e convexas, não foi considerado devido às limitações das ferramentas empregadas. Este trabalho apresenta análises bidimensionais (2D) e tridimensionais (3D), teoricamente mais rigorosas e adequadas para a geometria da barragem. As análises de estabilidade do maciço foram realizadas utilizando o Método Geral das Fatias e das Colunas (GLE), por meio do software SVSLOPE. Foram realizadas buscas por superfícies críticas 2D e 3D, ao longo de todas as zonas da estrutura. Considerando-se parâmetros de resistência drenada, observou-se que Fundão se encontraria em condições de elevada segurança, sendo o menor Fator de Segurança igual a 1,744. Valores próximos de 1,0 foram obtidos considerando rejeitos na condição não drenada, supostamente menos representativa das condições reais de campo. Os Fatores de Segurança 3D se mostraram muito próximos dos 2D, porém com variações significativas nas regiões côncava e convexa. Desta forma, conclui-se que o formato próximo à região do recuo exige maior atenção e análises 3D podem identificar as regiões críticas. ABSTRACT: The failure of the Fundão Dam, the largest disaster of its kind in the world, was studied by Morgenstern et al. (2016) using two-dimensional approaches. The carried out investigation did not point to mechanisms of slope instability as the causes of the disaster. However, the complex shape of the dam and its concave and convex regions were not originally considered due to limitations of the analysis tools employed. This paper presents two-dimensional (2D) and three-dimensional (3D) analyses that are more rigorous and well suited for the Fundão dam geometry. Slope stability analyses were accomplished using the General Limit Equilibrium Method of Slices and Columns (GLE) using the SVSLOPE software. Critical slip surfaces were searched in 2D and 3D, across the entire dam face. Drained shear strength parameters led to Factors of Safety that would indicate fairly stable conditions, with a lowest Factor of Safety of 1.744. Values close to 1.0 were obtained considering undrained conditions of the tailings, which are supposedly less representative of field conditions. The 3D factors of safety were very close to the 2D values, but with noticeably higher variations near the concave and convex regions. This leads to the conclusion that the dam shape near the setback region requires closer examination by means of 3D analyses that enable the identification of critical zones.

This chapter is dedicated to the presentation of the most popular methods of analysis employed to solve geotechnical boundary value problems, with special emphasis on the assessment of the potential hazards related to tunnelling. In particular, in Section 9.1, the general framework is outlined with reference to numerical solutions of coupled hydro-thermo-chemo-mechanical boundary value problems. In Section 9.2, the excavation phase is considered by analysing the response of the soil/rock mass close to the tunnel (‘near field’), whereas in Section 9.3, far-field tunnelling-induced modifications in stress and deformation fields and, if relevant, in the pore pressure distribution during the construction are considered. These analyses are instrumental in the assessment of the tunnel stability and in the design of the primary and final linings. Specific emphasis is given to some particularly demanding situations for tunnel construction and performance (i.e. rock burst phenomena, swelling or squeezing behaviour of the rock mass, etc.) requiring non-standard approaches to be implemented. Lastly, in Section 9.4, long-term system response is analysed. The accent is put on: (i) delayed/evolving with time strain and stress distributions (viscous and hydro-chemical effects, Section 9.4.1–9.4.3), (ii) seismic perturbations, (iii) gravitational and tectonic movements (landslides and faults) and (iv) thermal loading (fire in tunnel).

PT X had an accident of slope failure that caused fatalities and injuries experienced by labor mining, and also some heavy mining equipments buried by material s that causing companies g ot financial loss. therefore important to analyze the slope stability of surface mining operation, and predicting total volume of slope failure to anticipate the impact of fatalities/ injuries and financial risks. This research aim is to analyze slope stability before failure conditions, predicting volume of slope failure, and determine position of critical zone using limit equilibrium “Simpilfied Bishop” method 3-dimensional, then doing validation with calculation of actual volume by comparing results of topography maps before and after failure using the cut and fill method. From the result of research, the slope on unstability conditions, actual and predicted volume of slope failure is 8,629 m 3 and 10,559 m 3 , so percent of calculation error is 18.3% .

Gravel collapse caused by instability of dangerous rock mass is one of the common geological disasters in mountain highway. Identifying the safety and stability of dangerous rock and adopting corresponding treatment measures have great significance for ensuring the safety of mountain roads. Based on the field investigation of dangerous rock mass on the secondary road, the author found that the in stability and failure modes of dangerous rock in a mountainous were mainly slipping and dumping. This paper uses the limit equilibrium method to analyze the stability of the dangerous rock and verifies the safety factor of dangerous rock mass under different working conditions. According to the analysis results, the treatment measures of removing, anchoring and laying active protective net are put forward by the author, which provides a reference for the design, construction and research of similar projects.

The present study proposes a new approach to solve passive earth pressure problems using the method of slices, coupled with the limit equilibrium (LE) technique. Unlike existing LE studies...

Talus deposits naturally form to a certain height in the toes of slopes because of the accumulation of collapsed material and small landslides. However, the stability of concealed cataclin...

A numerical analysis on the stability of soil–cement column-reinforced riverbank along a river delta region in Viet Nam is presented in this paper. The numerical analyses based on the limit equilibrium method (LEM) were performed to assess the safety factor of the column-reinforced riverbank system under various river water level (RWL) conditions. Several factors influencing the riverbank slope stability including the position, length, quantity of soil–cement columns, and RWL changes were investigated. The simulated results showed that the riverbank stability is improved with an increase in the column quantity and the column length when subjected to a constant RWL. Moreover, the predicted results by LEM indicated that the column location and the RWL change significantly influence the stability of riverbank with column reinforcement. The column location between the middle and the slope toe had a significant improvement of the riverbank slope stability, where an initial drawdown of RWL resulted in a notable reduction of the riverbank slope safety factor. These factors should be taken into consideration in the design of a riverbank slope, reinforced with columns, under variable RWL. It is worth mentioning that the use of soil–cement column-reinforced riverbank could be a practical and possible engineering countermeasure to prevent a steep riverbank slope under RWL variations from sliding failure.

In this paper, the formation mechanism of a slightly inclined bedding mudstone landslide in the overlying mountain of the coal mining subsidence area of the Tanshan Coal Mine in Ningxia, China, is studied. By means of geotechnical investigation, indoor geotechnical tests, theoretical analysis and other technical means, we find the geological environment background of the study area and obtain the physical and mechanical property indexes of the mining landslide in the Tanshan Coal Mine. By combining the numerical simulation of discrete elements and finite elements, the macro deformation and failure law of the mining mudstone landslide and the displacement and stress nephogram of the failure process are discussed. The results show that the slightly inclined bedding mudstone landslide in the Tanshan Coal Mine is 850 m long from east to west, 500 m wide from north to south and 10,875,000 m3 in volume. It is composed of Jurassic mudstone and is a traction landslide caused by the coal mining subsidence area. The formation of the landslide is affected by internal factors and inducing factors. The internal factors are mainly geotechnical types and engineering geological properties, and the inducing factors are mainly coal mining activities and rainfall. By analyzing and summarizing the calculation process of the slope model prior to the landslide in 2D-Block and GeoStudio numerical simulation software, the sliding process of the slightly inclined bedding mudstone landslide in the Tanshan Coal Mine is divided into four stages: slope creep, slope deformation, landslide movement and landslide accumulation. GeoStudio software is used to calculate the stability of the Tanshan Coal Mine landslide under natural and rainfall conditions. The landslide is in a stable state under natural conditions and is basically stable under rainfall conditions. By comparing the calculation results of the limit equilibrium method and the finite element limit equilibrium method, we find that the calculated stability coefficient is more accurate when the appropriate constitutive model is selected. The research results have important reference significance for the prevention and control of the gently inclined bedding mudstone landslide of the overlying mountain in the coal mining subsidence area of the Loess Plateau.

The stability of an open-pit slope is an extremely important factor related to the safe production of an open-pit mine. It is the first safety technical problem encountered and should be solved in the process of mine design and production. By the means of an engineering geology and hydrogeological investigation of the waste dump area of the Nayuan open-pit coal mine and numerical simulation research, this paper analyzes and studies the slope stability of the stope and waste dump of the Nayuan open-pit coal mine in detail and puts forward measures such as slope prevention and automatic monitoring to achieve the goal of protecting the slope of the stope and waste dump and the surrounding environment. The main research results are as follows: (1) The geotechnical physical and mechanical indexes of stope and waste dump are collected and analyzed, and the geotechnical mechanical indexes in this report were determined, which basically meet the requirements of slope stability analysis. (2) The limit equilibrium method and finite element method were used to analyze and evaluate the current slope stability of the Nayuan open-pit coal mine. It was concluded that the foundation of the waste dump is basically stable, and the potential landslide modes of the slope are arc-shaped sliding surface and arc-shaped straight-line sliding surface. The numerical simulation and checking results showed that the current stope and waste dump slope are stable. (3) According to the analysis and evaluation results of slope stability, feasible slope prevention measures are put forward. The research results are of great significance to the safety of important facilities in open-pit mines and provide a basis for the design and safety implementation of open-pit slope engineering.

The objective of this study consisted of assessing the potential of limit equilibrium method equations and their scope, as well as advantages and limitations, with the possibility of application linked to geographical information systems (GISs) for mapping critical areas. The slope stability analysis is a study that allows to identify the stability conditions in areas of irregular relief, especially the slopes susceptible to gravitational mass movements. In this sense, the slopes in a region of the Serra do Mar Paranaense (Brazil) were treated as being infinite, with a homogeneous soil mass defined by their granulometric characteristics previously determined in characterization test carried out on both deformed and undeformed samples and, in general, with a rupture subsurface parallel to the surface of the slope. The parameters and variables involved in the analysis consisted in the equilibrium of the mobilizing forces and the resistive forces acting on the soil mass, following the equilibrium model. In comparison with the different equations, the limit equilibrium method (LEM) of infinite slopes with rupture surface under the root–soil system proved to be the most appropriate to be applied to the natural slopes. This method is very suitable for the analysis of stability of natural slopes, with great predictive power and, in addition, with possibilities to be applied at regional scale.

The construction of new roads and the extension of existing ones on natural slopes often requires the excavation of very steep cut slopes. Such slopes become vulnerable under the influence of factors such as heavy rainfall, dynamic loading, weathering effect and various kinds of human intervention. Along several Rwandan main roads, cut slope failures recently caused a lot of damage to housing, infrastructures and crops as well as loss of lives. Based on field observations and variations in geological and geotechnical conditions, this paper presents a simplified way in which the classical geotechnical methodology could be applied to slope stability analysis, to be used for stabilization works. Three representative sample sites in the Rwandan context, recently subjected to landslides, were chosen to carry out a detailed study, including laboratory tests and numerical analyses. The conventional two-dimensional limit equilibrium method was used to analyse the representative cut slopes. Slope stability analyses are conducted not only to reproduce the failure events, to be used as back analyses, but also to propose potential remedial works, that could be assumed as an example for other similar situations. The obtained results show how, at least in most common situations, it is possible to obtain a reliable design for stabilizing works on cut slopes by applying classical geotechnical methodologies.

This paper presents a set of new required programmes written in format data using the built-in programming FISH language available in three-dimensional Fast Lagrangian Analysis of Continua software (FLAC3D). These script data files were developed, to overcome difficulties noted during the nailed slope stability prediction. They established to analyse stability of general embankment slope cases under various soil nailing parameters design. To deal with 3D finite difference analysis results in terms of the factor of safety (FOS) and critical slip surface, both 2D finite difference and limit equilibrium (LEM) methods are also conducted. A comparison of the 3D and 2D results indicates that 2D analyses underestimate seriously stability predictions, notably in terms of the FOS. Therefore, it was concluded that, 3D analysis should be used as an alternative to the 2D analyses, even though it requires more time. Some useful conclusions are obtained from this work, which provides a good practice guidance for real life scenarios.

The determination of slope failure areas plays an important role in slope stability problem. The previous studies evaluate the failure area either based on the slip surface with minimum factor of s...

Spectral seismic bearing capacity of strip foundations is evaluated by the limit equilibrium method (LEM). In this study, the pseudo-dynamic approach is followed to take into account seismic accele...

This paper investigated the effect of the anisotropy of the internal friction angle on the seismic bearing capacity factor of shallow foundations placed over a frictional soil deposit with the adop...

El presente artículo explica el algoritmo y la implementación que se plantea para generar de forma automática el empaquetamiento de círculos de diferentes diámetros que se acomodan de forma tangencial en cada triángulo de un arreglo de triángulos que cubren un polígono cerrado R^2 La manera de generar este empaquetamiento es recursivo a varios niveles de profundidad, lo que genera partículas de diferentes diámetros que tiende al modelo a ser autosimilar para el intervalo de partículas más pequeñas y se desvía para partículas grandes. Sin embargo, se logra autosimilitud en los diámetros apagando o borrando algunas partículas pequeñas. La autosimilitud así lograda es dependiente de la forma del polígono cerrado. Cuando dicho polígono cerrado representa el marco geométrico de un talud en R^2 (una forma de polígono cerrado especial y tradicional para este tipo de problemas geotécnicos) se generan partículas autosimilares para representar geomateriales compuestos por bloques de roca embebidos en una matriz de suelo (bimsoils, acrónimo del Inglés blocks--in--matrix soils). Con este modelo geométrico generado es posible analizar la estabilidad de taludes mediante el método de equilibrio límite o mediante un análisis de esfuerzo--deformación. El algoritmo y la implementación está asociados al desarrollo de un software de aplicación denominado circpacker, el cual está escrito en PYTHON3 y se lo presenta a la comunidad como un código abierto y libre.

The results of physical modeling of deep pit slopes with equivalent materials are presented. The checking calculation is preformed using the limit equilibrium method. The displacements in the model are determined, and the safety factors of stable slopes are calculated at all stages of modeling. The pattern of deformation and failure of pit slopes is analyzed starting from the first manifestations till total instability at different strength characteristics of bedding interfaces. It is found that failure mechanism of pit slopes with steep bedding is governed by shear strength of interfaces. When the interfaces and rock mass have similar strength characteristics, pit slope deforms along a smooth curved sliding surface by the similar mechanism of an isotropic slope. In the presence of interfaces with much lower strength characteristics than the rock mass strength, the slope deformation has the mechanism of flexure toppling. In an intermediate variant, it is most probable that failure follows the mechanism of bending with subsequent shear of the layers along a curved surface.

This paper focuses on the failure of the soil around a pile, and proposes a simplified analytical method for calculating the uplift capacity of a single pile. In this method, a curved failure mechanism is built by taking into consideration the non-homogeneity of the soil. Then the uplift capacity formula for a single pile is deduced based on a nonlinear failure criterion and limit equilibrium method. Further the proposed method is validated by comparison against the numerical simulation results. The effect of the non-homogeneity of the soil and nonlinear strength coefficients on the uplift capacity of the pile is investigated. Results reveal that the uplift capacity of a single pile increases when the non-homogeneity constant of the soil increases, whereas it decreases when the nonlinear strength coefficient increases; increasing the pile length is, to a certain extent, an effective measure to improve the uplift capacity. These conclusions may serve as good references for the future design of uplift piles.

Torrential rainfall has a detrimental impact on the stability of soil-based agricultural embankments due to seepage and slope failure. The impact on the stability of an embankment due to rainfall patterns is specific to the geography, topography, and geometry of the embankment. However, this stability has not been widely assessed and updated with respect to new climate regimes. In this study, the slope stability of an agricultural embankment was evaluated based on five synthetic rainfall patterns derived from actual heavy rainfall events. The rainfall patterns were generated based on common patterns of rainfall hyetographs used in hydrological design and practice. The stability of the embankment was computed using the limit equilibrium method. Results of the stability analyses revealed time-series slope instability under rainfall patterns, and particularly the rainfall pattern that caused the most instability to the embankment was identified. Therefore, reassessment of the stability of the embankment in potential areas prone to heavy rainfall and flooding is beneficial to the preparation of early warning and emergency planning and preparedness as countermeasures for mitigating sediment-related hazards and disasters.

To better assess the stability of tunnel faces in cohesion-frictional soils, tunnel face stability was investigated considering the soil arching effect in this study. An improved 3D rotational failure model based on the limit analysis method and an improved wedge-prism model based on the limit equilibrium method were proposed. Simultaneously, the lateral stress ratio K s was improved to reflect the soil arching effect. The support pressures obtained by the two proposed models were validated by the numerical results and existing works. Finally, the effects of the geometrical and geotechnical parameters and loading conditions on the tunnel face stability were assessed.

By application of the limit equilibrium method associated with Coulomb failure mechanism, the effect of variation of undrained shear strength with depth on seismic bearing capacity was eval...

Previously, the stability analysis of seismically induced landslides was investigated by the factor of safety of the entire sliding body, which provided no information on the displacements of the analyzed seismically induced landslides. The landslides are assessed to be dangerous when the minimum value of the factor of safety (Fs) is less than a critical value. However, unlike the landslides subjected to static loads, the dynamic safety factors of seismically induced landslides vary with time. The minimum value of the dynamic safety factors being less than the critical value does not necessarily imply failure of the seismically induced landslides. In this paper, the three-dimensional displacement-based rigorous limit equilibrium method is proposed to study the displacements of seismically induced landslides. The relationship between the shear stresses acting on the base of the columns and the shear displacements is established based on the hyperbolic soil model. By introducing the strength reduction technique, the relationship between the reduction factor (RF) and the accumulated vertical displacement can be obtained. According to the definition of the strength reduction method, the safety factors of seismically induced landslides are determined, which do not vary with time. Then, the landslides can be assessed to be dangerous when the minimum value of Fs is less than a critical value.

The Green-Ampt (GA) model is one of the most widely used analytical methods of slope stability under rainfall. However, it may overestimate the soil water content above the wetting front. In this study, a novel approach to evaluate the time-dependent slope stability during intense rainfall based on a modified GA model is presented, and is known as the stratified Green-Ampt (SGA) model. By considering the stratified soil water content above the wetting front, the soil above the wetting front can be divided into saturated and transitional layers, and the SGA model is used to analyze the infiltration process of intense rainfall into slopes. Thereafter, safety factors (Fs) of infinite and finite slopes are derived using the SGA model. In the analysis of an infinite slope, the conventional limit equilibrium method is adopted to calculate the safety factor; as for a finite slope, the residual thrust method is introduced to obtain the safety factor with sliding mass divided into multiple soil slices. The performance of the SGA model is illustrated in two cases: an infinite slope and the Majiagou landslide as a finite slope. The results indicate that compared to the GA model, the calculated wetting front based upon the SGA model moves faster, and the wetting front depth shows a positive correlation with the slope surface angle and rainfall intensity. The evolution of the safety factor above the sliding surface can be divided into three phases, while the evolution of the safety factor above the wetting front can be divided into two phases. The critical time of the slope reaching a less stable state (safety factor is 1.05) or unstable state (safety factor is 1.00) decreases exponentially with an increase in rainfall intensity. In addition, the rainfall has a significant influence on the design of stabilizing piles for the Majiagou landslide. The presented SGA model appears to be accurate to investigate slope stability during intense rainfall events.

Construction of the Lau Simeme Dam used a tunnel as a diversion channel. Slopes at the diversion tunnel portals were prone to failure due to the tunnel excavation and earthquake. Earthquake load was not considered in the designs of the inlet and outlet portal slopes. This research evaluated stability of the tunnel portal slopes under static and earthquake loads using limit equilibrium methods of the Bishop Simplified and Morgenstern-Price. Input material properties for the slope stability analyses were obtained from evaluations of soil and rock cores, including determination of lithology type and rock mass quality based on Geology Strength Index (GSI), and laboratory testing. Evaluations of soil and rock cores indicated that the inlet portal slope consisted of residual soil, good quality tuff breccia, and good quality sandstone. The outlet portal slope consisted of residual soil, poor quality sandstone, poor quality tuff breccia, fair quality sandstone, fair quality tuff breccia, and good quality tuff breccia. The earthquake load coefficient determined by the seismic analyses based on the peak ground acceleration map for 10% probability exceedance in 50 year was 0.125 g. The slope stability analyses showed that the designed inlet and outlet portal slopes were stable under static and earthquake loads. The Bishop Simplified and Morgenstern-Price resulted in relatively similar Fs values. The Fs values of the inlet and outlet portal slopes decreased with the earthquake load application. Although Fs values of the outlet slope under static and earthquake loads met the requirements specified by SNI 8460:2017, the rock mass conditions, particularly the poor rock masses of layers 2 and 3, required special attention. Application of slope reinforcement methods, such as shotcrete, is suggested to further increase the slope stability.

Anchor cables are now widely used to stabilize many kinds of geostructures in practice. However, the prediction of the anti-pullout performance of anchor cables still involves uncertainty for designer. This paper presents an analysis procedure for the evaluation the ultimate pullout capacity of anchor cables embedded in rock. A unified rupture shape model is proposed to describe the failure surface shape of anchor in rock mass by incorporating typical failure mode and failure surface shape. Using the limit equilibrium method, a formula of ultimate pullout capacity of a single anchor (cable) considering layout pattern, grouting pressures, rock masse quality and construction disturbance is then established with the assumption that surrounding rock follows the generalized Hoek–Brown criterion. Performance of the present method is assessed using comparison of the theoretical and well-documented filed test results. Parametric study is also carried out to clarify the influence of some key indices for rock mass on the ultimate pullout capacity of anchor cables embedded in rock. The present analyses shows that the geological strength index has great influence on ultimate pullout capacity of a single cable and ultimate pullout capacity of a single cable could be improved to a certain extent by reducing construction disturbance.

In this paper, a method is presented for a simplified analysis of cantilever diaphragm walls in cohesive soils under undrained and drained conditions. A rectilinear distribution of the net contact stresses that are not completely predetermined by the limit state is assumed at the soil-wall interface, consistently with the mechanism usually experienced by these structures. Simple equations are derived to readily calculate the contact stress distribution on the wall and the associated internal forces in the ultimate and service conditions. Moreover, these equations require few parameters as input data. Comparisons are carried out with a limit equilibrium method commonly used in design to show the usefulness of the proposed method for practical purposes.

A deterministic model for the factor of safety of an idealized rock mass for planar mode of failure is developed adopting Limit Equilibrium Method (LEM) using Patton’s shear strength criterion and considering practically occurring conditions such as the effect of tension crack, water filled up in tension crack, horizontal and vertical seismic acceleration, rock bolt stabilizing force and surcharge. In the Pseudo-static analysis horizontal seismic acceleration is taken outward from the slope and vertical seismic acceleration is considered in both the direction i.e. towards the direction of gravity (downward) and opposite to the direction of gravity (upward). An expression of normal stresses as limiting criterion has been derived in order to compare the field normal stresses along the failure surface. A detailed parametric study has been presented to investigate the influence of vertical seismic coefficient for both the direction on the stability of rock slope using developed expression. For high normal stress along the failure plane, it is observed that the factor of safety decreases with increase in the value of vertical seismic coefficient towards the direction of gravity and increases linearly with increase in the value of vertical seismic coefficient against the direction of gravity and the opposite trend has been found for lower normal stress. The vertical seismic coefficient against the direction of gravity has predominant effect on factor of safety of rock slope as the rate of increase/decrease of factor of safety with vertical seismic coefficient is more against the direction of gravity. Hence in determining the critical factor of safety, effect of vertical seismic coefficient against the direction of gravity should be considered.

In order to improve the stability of expressway slope, an elastic-plastic analysis method based on finite element analysis is proposed. The limit equilibrium method is used to calculate the safety factor of slope. According to the calculation results, the sliding surface of the slope is determined. Based on the determined slope sliding surface, the finite element method is used to complete the finite element simulation of sliding surface, and the discrete finite element matrix is constructed to complete the elastic-plastic analysis of expressway slope stability. Experimental results show that, compared with traditional research methods, the proposed method can extract slope safety factor more accurately and improve the efficiency of analysis.

The performance of conventional rigid retaining wall under harmonic and transient ground motions is evaluated using three-dimensional finite element (FE) simulations. Rotation of wall about the base is found to be the predominant failure mechanism of the gravity retaining wall under seismic excitation. Earth pressure distribution corresponding to the peak ground acceleration is found to be nonlinear and unique in shape. The earth pressure distribution is strongly related to the rotational movement of the wall. Existing force-based methods for rigid retaining walls overestimated the earth pressure under seismic conditions compared to these numerical simulations.

The method for locating the critical slip surface or calculating the minimum safety factor of a slope based on the limit equilibrium method regards soil as a rigid-plastic material, which is inconsistent with reality. A new method for locating the critical slip surface of a slope based on an improved salp swarm algorithm (ISSA) and vector sum method (VSM) is proposed in this paper. ISSA consists of Levy’s flight (LF) strategy, chaotic local search (CLS) strategy, and salp swarm algorithm (SSA). The test results of five benchmark functions show that ISSA greatly improves the performance of SSA. Three slope cases show that the results of ISSA are closer to the global optimal solution than SSA. Compared with the proposed method, the limit equilibrium method underestimates the minimum safety factor of the slope.

In the present study, different approaches for determining seismic bearing capacity of shallow foundations have been discussed and a comparison has been drawn between seismic bearing capacity of shallow foundations of various widths and foundation depths, resting on both horizontal and sloping grounds. In general, the bearing capacity of foundations for static loading condition has been extensively studied by many researchers in the past. However, limited studies have been found from literatures which highlight the effect of an earthquake event on the bearing capacity of shallow foundations, especially when the foundation is resting on a sloping terrain. In this study, Sarma and Iossifelis (Geotechnique 40(2):265–273, 1990, [1]), Richards et al. (J Geotech Eng, ASCE 119(4):662–674, 1993, [2]), Budhu and Al Karni (Geotechnique 43(1):181–187, 1993, [3]), Soubra (Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, London vol 125(4), pp 230–241, 1997, [4] and 1999), Kumar and Rao (Geotechnique 52(2):79–88, 2002, [5]), and Cascone and Casablanca (Soil Dyn Earthq Eng 84:204–223 2016, [6]) have been studied for computing seismic bearing capacity of shallow foundations of various widths resting on horizontal ground. Similarly, the seismic bearing capacity of shallow foundations of various widths resting on sloping ground has been computed by methods provided by Kumar and Rao (Geotechnique 53(3):347–361, 2003, [7]), and Chaudhary and Rao (Int J Geomech, ASCE 6(3):176–184, 2006, [8]). In the end, the seismic bearing capacity of shallow foundations with varying widths for horizontal and sloping grounds has been compared as obtained from different methods. This study helps in understanding the basic mechanism of load transfer from foundations to the surrounding ground as well as highlights on differences and similarities among different analytical solutions available for determining seismic bearing capacity of shallow foundations.

In this paper, an attempt is made to capture the seismic stability of a finite slope reinforced with micropiles using the original pseudo-dynamic (OPD) approach. The stability of the slope is evaluated using the limit equilibrium method considering c-ϕ soil. The study is performed by assuming a circular slip surface passing through the toe of the slope. The effect of various parameters such as horizontal (kh) and vertical (kv) seismic acceleration coefficients, slope angle (i), angle of internal friction of the soil (ϕ), amplification factor (fa) and angle of inclination of micropiles (θb) on the stability of the slope is explored in terms of the factor of safety (FOS). Under the seismic condition, the stability of a slope along with micropiles is found to be affected less compared to that of a slope without micropiles.

In engineering, retaining walls commonly rotate about the base (RB) and narrow backfill is often compressed. Current methods cannot accurately predict the passive earth pressure of a narro...

The fluctuation of reservoir water levels has significant impact on bank slope stability near a reservoir. Therefore, it is necessary to analyze the stability of bank slopes with reservoir...