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1

Stability analysis of the slope subjected to the dynamic loading

Zabuski Lesław

Zeszyty Naukowe. Transport / Politechnika Śląska

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2023

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z. 118

243--255

EN

This paper presents the results of a stability analysis of a slope located in the immediate vicinity of a railway line. The plans for the extension of this railway track include the construction of another line, which would run parallel to the existing one, within a few metres distance. It is expected that intensive goods train traffic will generate both static and dynamic forces in the underlying subsoil. Consequently, seismic vibrations will be generated in the subsoil, propagating mainly not only in the horizontal direction but also in the vertical direction. The method of seismic coefficient of the earthquake intensity determined by a pseudo-static method and horizontal component of acceleration is appropriate and recommended because it is simple, and the safety factor of the slope is calculated in the same way as in conventional stability calculations.

2

Assessment of slope stability using classification and regression algorithms subjected to internal and external factors

Singh Sudhir Kumar, Chakravarty Debashish

Archives of Mining Sciences

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2023

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Vol. 68, no. 1

87--102

EN

This study aims at developing a machine learning based classification and regression-based models for slope stability analysis. 1140 different cases have been analysed using the Morgenstern price method in GeoSlope for non-homogeneous cohesive slopes as input for classification and regression-based models. Slope failures presents a serious challenge across many countries of the world. Understanding the various factors responsible for slope failure is very crucial in mitigating this problem. Therefore, different parameters which may be responsible for failure of slope are considered in this study. 9 different parameters (cohesion, specific gravity, slope angle, thickness of layers, internal angle of friction, saturation condition, wind and rain, blasting conditions and cloud burst conditions) have been identified for the purpose of this study including internal, external and factors representing the geometry of the slope has been included. Four different classification algorithms namely Random Forest, logistic regression, Support Vector Machine (SVM), and K Nearest Neighbor (KNN) has been modelled and their performances have been evaluated on several performance metrics. A similar comparison based on performance indices has been made among three different regression models Decision tree, random forest, and XGBoost regression.

3

Strength reduction method in the stability assessment of vegetated slopes

Świtała Barbara

Architecture Civil Engineering Environment

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2023

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Vol. 16, no. 2

151--159

EN

The thoughtful design and mitigation of ecological slope stabilization measures rely heavily on the reliable assessment of the stability of vegetated slopes. This is a complex problem due to the many aspects of vegetation presence that must be taken into account. The numerical model should be able to consider mechanical root reinforcement and root water uptake, which can lead to soil desaturation. This paper presents the application of the strength reduction method to the Modified Cam-Clay model for unsaturated, root-reinforced soils, which allows for the quantitative estimation of slope stability. The technique is implemented in finite element software and tested using several numerical examples. Firstly, the sensitivity of the factor of safety to changes in root constitutive parameters is investigated. In the second example, the stability of the modelled slope is assessed under rainfall of a certain duration followed by progressively modifying soil strength parameters until failure occurs. Furthermore, slope stability is assessed for various durations of the rainfall period.

4

Stability of open pit lignite excavations during flooding. Comparison of a simplified analytical tool with limit equilibrium computational analysis

Kontopidis Orestis, Theocharis Alexandros I., Koukouzas Nikolaos C., Zevgolis Ioannis E.

Górnictwo Odkrywkowe

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2022

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R. 63, nr 3

4--9

EN

A common practice for valorizing abandoned open-pit mines is flooding them to form pit lakes. Slope stability in post-coal areas is critical due to failure incidents reported in surface coal mines during operation and valorization. An analytical model was recently presented concerning evaluating the pit lake’s slope stability in the presence of a weak zone. The present work compares that analytical model with a limit equilibrium computational approach for lignite mines’ stability. Assumptions of each model are discussed, and identical geometries and geotechnical parameters are implemented. It is concluded that the Safety Factor and its evolution are very sensitive to the water regime and the lake’s depth for the analytical model. On the other hand, the limit equilibrium analysis considering the same piezometric and lake levels proposes a drastically different SF evolution. Overall, the differences between the analytical and the limit equilibrium analysis might refer to different water conditions in practice and should be implemented with due caution.

PL

Powszechną praktyką rekultywacji byłych kopalń odkrywkowych jest zalewanie ich wodą w celu utworzenia zbiornika pokopalnianego. Stabilność zboczy na terenach poeksploatacyjnych jest parametrem krytycznym ze względu na przypadki zniszczeń występujące w kopalniach odkrywkowych podczas eksploatacji i rekultywacji. Ostatnio przedstawiony został model analityczny dotyczący oceny stateczności zboczy zbiornika poeksploatacyjnego przy obecności strefy osłabienia. W niniejszej pracy porównano ten model z obliczeniową metodą równowagi granicznej dla stateczności kopalń węgla brunatnego. Omówiono założenia każdego z modeli oraz wykorzystano identyczne geometrie i parametry geotechniczne. Stwierdzono, że w modelu analitycznym współczynnik bezpieczeństwa i jego zmiany są bardzo wrażliwe na reżim wodny i głębokość zbiornika. Z drugiej strony, analiza metodą równowagi granicznej, uwzględniająca te same poziomy wody w piezometrach i zbiorniku, wskazuje na radykalnie inny proces zmian współczynnika bezpieczeństwa. Ogólnie rzecz biorąc, różnice pomiędzy modelem analitycznym a metodą równowagi granicznej mogą w praktyce odnosić się do różnych warunków wodnych i powinny być wdrażane z należytą ostrożnością.

5

Deep neural network and ANN ensemble for slope stability prediction

Gupta A., Aggarwal Y., Aggarwal P.

Archives of Materials Science and Engineering

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2022

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Vol. 116, nr 1

14--27

EN

Purpose: Application of deep neural networks (DNN) and ensemble of ANN with bagging for estimating of factor of safety (FOS) of soil stability with a comparative performance analysis done for all techniques. Design/methodology/approach: 1000 cases with different geotechnical and similar Geometrical properties were collected and analysed using the Limit Equilibrium based Morgenstern-Price Method with input variables as the strength parameters of the soil layers, i.e., Su (Upper Clay), Su (Lower Clay), Su (Peat), angle of internal friction (φ), Su (Embankment) with the factor of safety (FOS) as output. The evaluation and comparison of the performance of predicted models with cross-validation having ten folds were made based on correlation-coefficient (CC), Nash-Sutcliffe-model efficiency-coefficient (NSE), root-mean-square-error (RMSE), mean-absolute-error (MAE) and scattering-index (S.I.). Sensitivity analysis was conducted for the effects of input variables on FOS of soil stability based on their importance. Findings: The results showed that these techniques have great capability and reflect that the proposed model by DNN can enhance performance of the model, surpassing ensemble in prediction. The Sensitivity analysis outcome demonstrated that Su (Lower Clay) significantly affected the factor of safety (FOS), trailed by Su (Peat). Research limitations/implications: This paper sets sight on use of deep neural network (DNN) and ensemble of ANN with bagging for estimating of factor of safety (FOS) of soil stability. The current approach helps to understand the tangled relationship of various inputs to estimate the factor of safety of soil stability using DNN and ensemble of ANN with bagging. Practical implications: A dependable prediction tool is provided, which suggests that model can help scientists and engineers optimise FOS of soil stability. Originality/value: Recently, DNN and ensemble of ANN with bagging have been used in various civil engineering problems as reported by several studies and has also been observed to be outperforming the current prevalent modelling techniques. DNN can signify extremely changing and intricate high-dimensional functions in correlation to conventional neural networks. But on a detailed literature review, the application of these techniques to estimate factor of safety of soil stability has not been observed.

6

Geophysical investigation and the use of their results in the evaluation of the stability of slopes of artificial water reservoirs in the flysch Carpathians

Bestyński Zbigniew, Sieinski Edmund, Śliwiński Piotr

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

71--85

EN

The article presents the possibility of using geophysical surveys to assess the stability of Carpathian slopes built of flysch deposits susceptible to mass movements. Landslide slopes located in the coastal zone of artificial water reservoirs are particularly susceptible to the loss of stability due to the erosion of this zone and the changing water level in the reservoir. Geophysical surveys of landslides carried out as a part of the research programs: PR-7 carried out by IMGW in 1972-1980 and SOPO carried out by PGI in 2009-2016 made it possible to develop a methodology of geophysical surveys enabling the determination of the geometry (course of the slip surface and range levels) of the existing landslides, information necessary to carry out a computational analysis of their stability. Examples of geometry of landslides in the coastal zone of the Czorsztyn reservoir and landslides in the area of hydrotechnical drifts of the Swinna-Poreba dam were presented. The possibility of a quantitative evaluation of the stability of the Carpathian slopes was also proposed on the basis of the SMR (Slope Mass Rating) proposed by M. Romana, using the KFG (Klasyfikacja Fliszu-Geofizyczna) geophysical classification equivalent to the RMR (Rock Mass Rating) classification by Z.T. Bieniawski for the assessment of the massif. A dozen or so active landslides were compiled for which the stability was determined using the SMR method.

PL

W artykule przedstawiono możliwość wykorzystania badań geofizycznych w ocenie stateczności zboczy karpackich zbudowanych z podatnych na ruchy masowe utworów fliszowych. Szczególnie podatne na utratę stateczności, z powodu erozji strefy brzegowej i zmiennego poziomu wody w zbiorniku, są zbocza osuwiskowe położone w strefie brzegowej sztucznych zbiorników wodnych. Badania geofizyczne osuwisk wykonane w ramach programów badawczych PR-7, realizowanego przez IMGW w latach 1972-1980 i SOPO, realizowanego przez PIG w latach 2009-2016, umożliwiły wypracowanie metodyki badań geofizycznych umożliwiających określenie geometrii (przebieg powierzchni poślizgu i poziomy zasięg) istniejących osuwisk, informacji niezbędnej do przeprowadzenia analizy obliczeniowej ich stateczności. Przedstawiono przykłady rozpoznania geometrii osuwisk w strefie brzegowej zbiornika Czorsztyn oraz osuwisk w rejonie sztolni hydrotechnicznych zapory Świnna-Poręba. Przedstawiono również możliwość ilościowej oceny stateczności zboczy karpackich na podstawie klasyfikacji SMR (Slope Mass Rating) zaproponowanej przez M. Romanę, wykorzystując do oceny masywu klasyfikację geofizyczną KFG (Klasyfikacja Fliszu - Geofizyczna) równoważną z klasyfikacją RMR (Rock Mass Rating) Z.T. Bieniawskiego. Zestawiono kilkanaście czynnych osuwisk, dla których określono stateczność metodą SMR.

7

Możliwości zastosowania zdalnego systemu monitoringu wgłębnego i powierzchniowego osuwisk w kopalni odkrywkowej węgla brunatnego na podstawie badań wykonanych w KWB Bełchatów w ramach projektu UE RFCS Slopes

Bednarczyk Zbigniew

Przegląd Geologiczny

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2021

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Vol. 69, nr 12

785--799

EN

Landslides in Polish opencast lignite mines are a serious problem for the efficiency of exploitation. They can also pose a threat to adjacent areas and the environment, and in some cases even jeopardize the continuity of lignite supplies to power plants. Such phenomena are associated with a number of factors, the most important of which are the geological engineering structure, groundwater conditions, unfavourable strength parameters of clayey soils and their usually relatively steep slopes. Counteracting such a phenomena, caused by mining activity, is usually difficult because of large size of landslides and the depth of exploitation reaching in some cases over 300 m. The paper presents the first application of on-line monitoring in a Polish opencast lignite mine. Performed in the Bełchatów Mine, in situ monitoring was complemented by satellite radar interferometry (PSI), LiDAR airborne laser scanning, and terrestrial laser scanning. Research within the RFCS EU SLOPES project “Smarter Lignite Open Pit Engineering Solutions” was performed by an international consortium from six European countries. In Poland, the research was located mainly on the western slope of the Bełchatów Field. In this area, in the Polish open pit lignite mine, on-line inclinometer, and a pore pressure monitoring system were the first located at the levels of+42 : -58 m a.s.l. Geological engineering investigations included 100 m depth core drilling, index laboratory tests, IL oedometer tests, CIU, CID triaxial tests, and numerical modelling. The total amount of in situ displacement, during the period December 2016-July 2019, reached 290 mm. The largest displacements up to 250 mm were recorded: to a depth of 45 m in the direction of slope inclination, and smaller ones up to 50 mm to a depth of 72.5 m. The displacements were accompanied by a decre ase in pore pressure values by more than 200 kPa. In other parts of the mine and adjacent areas, the satellite radar interferometry detected displacements up to 60 mm/year on the outer slopes of the Szczerców dump. It also allowed identification of the landslide hazard in other areas. Data obtained from in-situ monitoring and laboratory tests on the western slope of the Bełchatów Field were included in numerical modelling using the shear strength reduction method and the limit equilibrium method. This should allow helping for better recognition and warning of the existing hazards in the investigated area.

8

Static and dynamic analyses of the stability of mining wastes (Ravaneti) in the Carrara marble area (Apuan Alps, Italy)

Oreste P., Soldano S.

Archives of Mining Sciences

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2012

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Vol. 57, no. 3

667--686

EN

The problem of the stability of “ravanetos” (debris piles of mining waste material extracted from the Apuan Alps, Italy) is very relevant, because of the consequences a landslide would have on the people and the existing civil infrastructures throughout the territory. In this work, the stability of two ravanetos that can be considered as representative of those in the Carrara area has been studied: the Polvaccio ravaneto, a recent type of debris pile and the Torrione-Tecchione, an old debris pile at present undergoing re-naturalisation. The study using the LEM (Limit Equilibrium Method) in a static and pseudo-static field, has made it possible to first carry out a back-analysis to define the most probable apparent cohesion and friction angle values of the material that makes up the ravanetos. Subsequently, it was possible to determine the intensity of the seismic wave that would be able to lead the two ravanetos to limit stability conditions and to determine the probability of such a seismic wave occurring in the next 50 years. A more accurate analysis, carried out with a numerical method in the dynamic field, of the most critical condition (the Polvaccio ravaneto) has led to more conservative results (higher safety factors) than those obtained with the LEM. This result allows us to reveal how the LEM can be considered a cautionary instrument to judge the stability of debris piles during a seismic event and that the likelihood of a landslide occurring in the two studied representative ravanetos over the next 50 years is very slim.

PL

Zagadnienie stabilności hałd odpadów górniczych w regionie Alp Apuańskich, Italia) jest niezmiernie ważne z uwagi na skutki jakie ewentualne osunięcia gruntu mogłyby mieć dla ludności oraz budowli znajdujących się na tych terenach. W pracy tej rozpatrywano zagadnienie stabilności dwóch hałd odpadów, które uznać można za reprezentatywne dla regionu Carrera: hałda w Polvaccio (hałda nowszego typu) oraz Torrione-Tecchione, stara hałda, obecnie poddawana procesom rekultywacji. W badaniach zastosowano metodę równowagi granicznej (LEM) w polu statycznym i pseudo-statycznym. Metoda ta umożliwia w pierwszym rzędzie przeprowadzenie analizy wstecznej w celu określenia najbardziej prawdopodobnego pozornego kąta kohezji i tarcia dla materiału hałdy. Następnie określono intensywność fali sejsmicznej, w wyniku oddziaływania której hałdy mogłyby utracić stabilność a także obliczono prawdopodobieństwa wystąpienia takiej fali sejsmicznej w ciągu najbliższych 50 lat. Bardziej szczegółowa analiza warunków krytycznych, wykonana przy pomocy metod numerycznych w polu dynamicznym, dała bardziej ostrożne wyniki (wyższe współczynniki bezpieczeństwa) niż te uzyskane przy pomocy metody równowagi granicznej. Wyniki badań sugerują, że metoda równowagi granicznej stanowi ostrożne narzędzie do określania stabilności hałd odpadów w trakcie zjawisk sejsmicznych. Pokazano także, że prawdopodobieństwo wystąpienia osunięcia terenu w przeciągu kolejnych 50 lat w przypadku dwóch rozpatrywanych hałd jest bardzo niewielkie.

9

Monitoring of the slope stability - precision inclinometry

Sladkova D., Mazac J., Vrubel M., Bujok P.

Wiertnictwo, Nafta, Gaz

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2004

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R. 21/1

317-324

EN

Monitoring of a rock massif aimed at its slope stability often necessittates measurement of a horizontal deformation. The precision inclinometry, used in building industry, open-pit mining and in other fields of activity seems to by very accurate and reliable. For these purposes, there is the precision vertical inclinometer - type NMG (firm Glotzl Baumesstechnik, Germany) used, in Severoceske doly a.s., Chomutov. This paper deals with some experiences, acquired by application of this measuring apparatus at choice localities of this company with the main attention to its precision.

PL

Monitorowanie stabilności zbocza często wymaga zastosowania pomiaru deformacji poziomych. Precyzyjne pomiary upadu, często stosowane np. w budownictwie czy górnictwie odkrywkowym, wydają się być bardzo dokładne i niezawodne. Z tego względu w Severoceske doly a.s. zastosowano pionowy upadomierz precyzyjny typu NMG niemieckiej firmy Glotzl Baumesstechnik. W artykule przedstawiono doświadczenia zdobyte w czasie stosowania tego urządzenia pomiarowego w wybranych lokalizacjach, ze szczególnym uwzględnieniem jego dokładności.