Wyniki wyszukiwania - BazTech

1

Analysis of slope stability under variable water table conditions for pre-modernized and modernized levees

Lech Mariusz, Rabarijoely Simon, Bajda Marek, Markowska-Lech Katarzyna

Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej

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2025

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Nr 93 (tom 1)

43--58

EN

The catastrophic floods in Poland in previous years and the current one in 2024 have highlighted the importance of slope stability in the design, maintenance, and operation of levees, which are crucial for flood protection. While the causes of this year’s flood have not been determined yet, as experts are still working on assessing the reasons for the failure of various structures, it is evident that many have failed due to multiple factors, such as overtopping, internal erosion, and slope instability. The article highlights the importance of the observational method, which, during the operation of hydraulic structures often in use for decades, enables data collection on potential seepage through the levee and on adverse filtration phenomena. Such information allows revising previous safety calculations for the structure, adjustments of geotechnical parameters adopted during the design phase, and consideration of factors like the presence of water on the downstream side. Evaluating slope stability under these conditions reflects the actual working environment of the structure and facilitates decision-making regarding potential modernization initiatives. The article analyses the stability of the levee slope before and after its modernization. A transient seepage analysis through the levee was carried out in the selected cross-section for various water levels, and the stability of the embankment in such conditions was also assessed. Next, the modernization of the embankment was briefly described, with particular emphasis on the sealing system. Stability was evaluated under the new filtration conditions through the levee. Based on this, it was concluded that the sealing system plays a crucial role in improving the safety and stability of the slope. The analysis revealed that remedial actions alone—such as soil compaction and raising the levee crest—without the installation of sealing systems would have virtually no significant impact on the structure safety. After implementing the remedial measures, the levee safety factor can be considered safe, and the numerical analysis of water filtration through the levee indicates that future water seepage on the downstream side during river flooding should not occur.

2

Wykorzystanie popiołu lotnego do stabilizacji skarp wysokich hałd odpadów górniczych

Sternik Krzysztof, Olma Anna

Materiały Budowlane

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2025

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nr 3

61--66

3

The pore water pressure changes on forested slopes in tropical humid climate area

Hendrayanto, Fata Yulia Amirul, Askari Muhamad, Erizal, Tarigan Suria Darma, Suhartanto Ery

Journal of Ecological Engineering

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2025

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Vol. 26, nr 1

121--136

EN

This study investigates the pore water pressure and water content on a forested slope, focusing on the impact of canopy interception across various rainfall intensities. The study was performed on slopes in the Sukajaya Sub District of West Bogor, West Java, Indonesia, a region that encountered landslides in 2020. Soil hydraulic characteristics, soil textures, saturated water content, and soil moisture content at different pressures, were assessed at different slope locations and depths. The pore water pressure and water content change were simulated using the one-dimensional uniform (equilibrium) finite element model of water movement using the modified Richards and were executed with the HYDRUS 1D model across six scenarios of a combination of three rainfall events at two initial conditions of water content, contrasting bare and vegetated slopes of Maesopsis eminii, which exhibited 35% canopy interception. Findings demonstrate that bare soil attains saturation more rapidly, resulting in elevated pore water pressure and increased susceptibility to slope instability. Conversely, vegetated slopes have delayed saturation owing to canopy interception, which diminishes the volume of rainfall that reaches the soil. The results highlight the crucial function of vegetation in preserving slope stability by regulating soil water pressure and water content, particularly during intense rainfall events. This research enhances comprehension of how vegetated areas might reduce landslide hazards in high-rainfall environments.

4

Analiza numeryczna zachowania się skarpy gruntowej w warunkach zadanych wymuszeń dynamicznych

Okroj Paweł, Hulimka Jacek

Przegląd Budowlany

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2024

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R. 95, nr 1-2

44--49

PL

W artykule przedstawiono proponowaną metodę szacowania stateczności skarp gruntowych narażonych na oddziaływania dynamiczne w efekcie prowadzonych w pobliżu prac. Omówiono założenia metody oraz sposób weryfikacji uzyskanych wyników metodą porównania efektów analizy MES z wynikami bezpośrednich pomiarów drgań wierzchniej płaszczyzny gruntu w pobliżu frontu prac. Proponowaną metodę zilustrowano wynikami przykładowych analiz dla dwóch różnych gruntów budujących skarpę.

EN

The paper presents a proposed method for estimating the stability of ground slopes subjected to dynamic inputs as a result of work carried out nearby. The assumptions of the method and the verification procedure of the obtained results by comparison of the effects of FEM analysis with the results of direct measurements of vibrations of the topsoil plane in the vicinity of the work front are discussed. The proposed method is illustrated with the results of exemplary analyses for two different soils forming the slope.

5

The influence of water runoff pressure on the stability of natural and engineering slopes

Łupieżowiec Marian

Materiały Budowlane

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2024

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nr 8

33--45

EN

A very common reason for the loss of stability of slopes is water pressure resulting from weather conditions or changes in water filtration in the ground. The force resulting from these pressures is usually one of the main factors initiating the loss of stability. Stability is also influenced by changes in the water level in the slope after heavy rains. Stability taking into account the impact of water can be simulated using the finite element method using the c – φ reduction method.

PL

Bardzo częstym powodem utraty stateczności skarp i zboczy jest ciśnienie wody pojawiające się wskutek warunków atmosferycznych lub zmiany filtracji wody w podłożu. Siła będąca skutkiem tego ciśnienia przeważnie stanowi jeden z głównych czynników inicjujących utratę stateczności, na którą ma wpływ również zmiana poziomu wody w zboczu po wystąpieniu ulewnych deszczy. Stateczność z uwzględnieniem oddziaływania wody można symulować metodą elementów skończonych, stosując metodę redukcji c – φ.

6

Analiza czynników mających wpływ na stateczność skarpy hałdy pokopalnianej

Łupieżowiec Marian, Kowalska Magdalena, Wróblewska Magdalena

Materiały Budowlane

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2024

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nr 2

73--78

7

Application of Haines and Terbrugge chart for suitable slope angles - a case study of artisanal and small-scale mining

Mgiba Carol, Rupprecht Steven

Journal of Sustainable Mining

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2024

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Vol. 23, iss. 4

424--440

EN

Significant hazards in Artisanal and small-scale mining (ASM) are rock failure and slope collapse caused by overly steep pit walls, poor mine design and water pressure. There is a lack of expertise and capital in ASM. Providing a simple and cost-effective slope stability analysis and designing systems that can mitigate the risk of slope collapse is essential. This article aims to assess whether stability charts and estimations can be used to establish suitable slope angles to mitigate the overwhelming cases of slope collapse in ASM. The Bieniawski’s Rock Mass Rating system and Heins and Terbrugge stability chart were used to assess the stability of Small-scale mine slope and determine suitable slope angles. To validate the reliability of estimations, further analysis was performed through laboratory strength tests to find actual intact rock mass properties and create a model using OPTUM G2 to simulate the Hoek-Brown failure criterion. The study reveals that stability analysis using charts is applicable with the assistance of a rock engineering practitioner after exposing the intact rock mass to map discontinuities. The Heines and Terbrugge chart can be utilized to mitigate slope collapse in ASM, provided that the limitations of the stability graphs are recognized.

8

Geotechnical Zoning Map for an Industrial Area in the Castelo Branco Region (Portugal)

Ferreira-Gomes L. M., Mendes E., Andrade Pais L. J., Maia Carvalho P. E., Coelho-Ferreira P. J., Gonçalves V.

Inżynieria Mineralna

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2024

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Vol. 1, no. 2

art. no. 36

EN

Large-scale geotechnical zoning maps (  1/10 000) applied to Regional and Urban Planning (RUP), and also to the expansion of cities into new areas, such as new industrial areas, generally follow the classic methodology, which corresponds to the presentation of Geotechnical Units Map (GUM) in association with extensive tables with the characteristics of the various Geotechnical Units (GUs). The GUs are defined based on the different lithological and/or lithogenetic types. The tables associated with the GUMs present the characteristics of the various UGs, namely identification properties, in-situ physical parameters, strength parameters, and deformability parameters. In addition to these parameters, it is common to find geological, geomorphological, geodynamic, and hydrogeological elements, with the development of certain specificities depending on each region. In the present case study, in addition to the GUM, in association with some tables with a vast set of parameters, a Geotechnical Zoning Map (GZM) is presented, which is the result of a final document based on a methodology that the authors understand that it should always be used and standardized for this type of situation, i.e. the final map should be the result of overlaying three partial maps, according to the following: 1st Level – Topographic Map, with perfect reading not only of what is common in this type of map but also an adequate reading of the urban fabric, road network, and others.; 2nd Level - Classic GUM; this level must be presented in classic symbology for the different lithologies, so that, when overlapping the previous level, it is possible to read both levels; 3rd Level – GZM, which corresponds to a colour map, with relatively transparent colours, so that when overlaying the previous levels, it is always possible to collect information from the three levels; this last level will have several colours, the main ones being red, green and yellow, which correspond respectively to Very Poor, Excellent and Intermediate Suitability, concerning Suitability for Urban/Industrial Occupation; other intermediate colours may be used, depending on the classification of each area under study. Note that each colour corresponds to a Geotechnical Zone (GZ), representing the suitability for urban-industrial occupation of an area of the territory, as defined in the legend of this map. Therefore, the main objective of this paper is to present a case study with the above situations, but with the advance of applying a methodology that can be implemented with Geographic Information Systems (GIS) to obtain colour zoning, which will be a consequence of overlaying 3 new maps: i) Bearing capacity map for foundations; ii) Settlement susceptibility map, and iii) Slope stability map. Each of these analytical maps is the result of massive calculations using the parameters of each GU for the different places of the territory under study. It should be noted, for example, that different GUs, one made up of clays and the other of sands, which are completely different, can fall under the same GZ. The important point is to define a zoning in which the territory of each zone has the same reaction to any similar action, following what is commonly used for the dimensioning and implementation of urban buildings and/or other similar ones: bearing capacity, settlements, and stability of the natural slope. Finally, the GZM of the area under study is presented, with some conclusions.

9

Analiza stateczności skarpy klifu w ciągu brzegu morskiego w miejscowości Rozewie

Tisler Witold, Pałasz Wiktoria, Pierzchliński Tomasz, Piórkowska Natalia, Szulc Kacper

Builder

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2024

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R.28, nr 12

51--55

PL

Artykuł porusza problematykę stateczności klifu znajdującego się w strefie przybrzeżnej miejscowości Rozewie. Z uwagi na gęstą roślinność oraz wysoki poziom wód gruntowych zbocze osuwa się w stronę morza i może wymagać wzmocnienia. Ingerencję w zbocze utrudnia zalesienie obszaru oraz obecność drzew mających status pomnika przyrody. Obliczenia wykonane na potrzeby niniejszego artykułu skupiają się na określeniu stateczności zbocza dla wybranego przekroju, w którym stwierdzono najniekorzystniejsze warunki gruntowe. Symulacje wykonano w programie Slide2D wersja 6.0., który do obliczeń wykorzystuje metody równowagi granicznej. Stateczność z uwagi na złożony układ warstw gruntowych porównano dla czterech dostępnych modeli obliczeniowych: Fellenius, Bishop, Janbu, Spencer, które nie różniły się znacząco wartościami końcowymi. W analizie wariantowej sprawdzono również wpływ sposobu modelowania poziomu zwierciadła wody gruntowej oraz przyjęcia parametrów funkcji van Genuchetna odpowiedzialnej za przepływ wody w strefie aeracji. Bez względu na przyjęte parametry oraz założenia można jednoznacznie stwierdzić, że zapas bezpieczeństwa wynikający z oszacowanych wskaźników jest niewystarczający.

EN

The article discusses the problem of stability of the cliff located in the coastal zone in city Rozewie. Due to dense vegetation and high groundwater levels, the slope is sliding towards the Baltic sea and may require immediate strengthening. Unfortunately, all planed actions may be difficult to do because of high trees on the area with the status of a natural monument. The calculations performed in this article focus on determining the slope stability for the selected cross-section in which the most unfavorable ground conditions were found. The simulations were performed in the program Slide2D version 6.0, which uses the limit equilibrium methods for calculations. The slope stability due to the complex of soil layers was compared for four available computational models: Fellenius, Bishop, Janbu, Spencer, which did not differ significantly in final values. The variant analysis also checked the influence of the method of modeling the groundwater table level and the adoption of the parameters of the van Genuchten mathematical model. The mentioned function is responsible for the water flow in the aeration zone. Regardless of the adopted parameters and assumptions, it can be clearly stated that the safety margin resulting from the estimated factors is insufficient.

10

Stability analysis of ultra-high and steep reinforced soil fills slopes based on strength reduction

Gao Yucong, Zhao Yue, Xu Tianyuan, Xu Jinlong

Archives of Civil Engineering

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2024

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Vol. 70, nr 2

417--430

EN

The research focuses on solving the important problem of slope stability in the field of civil engineering. The study adopted an advanced strength double reduction coefficient method for slope stability analysis, which considers the different influence weights of cohesion and internal friction angle, and reduces them with different reduction coefficients to describe the stability of the slope. The simulation experiment results indicate that the attenuation degree of cohesion and internal friction angle affects slope stability. When the reduction coefficient of cohesion increases to 1.737 and the reduction coefficient of internal friction angle increases to 1.201, the slope is prone to instability and failure, and the safety factor of the calculated result is 1.493. Moreover, when the anti-slip pile is set in the middle of the slope (1/2), and the slope is in a critical state, the bending moment and shear force suffered by the anti-slip pile are both maximum, so the reinforcement effect is also the best.

11

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.

12

Control of Dump Stability Loading Rock on its Edge

Adamchuk Andrii, Shustov Oleksandr

Inżynieria Mineralna

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2023

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no. 1

91--96

EN

The question of the overburden rock dump formation during the development of iron ore deposits of Ukraine was considered. An analysis of the technology of forming a high single-tier dump in an abandoned deep pit was carried out. Two technology options are considered: loading rock on the slope of high single-tier dump and on its edge. The influence of the dependence of the loading rock on the edge of high single-tier dump on its stability of a has been established. The nature of the change in the width of the possible landslide prism, the safe distance of the dragline location has been established. The prospects for the formation of a high single-tier dump in the regime of controlled deformations are substantiated. For high single-tier dump the ordinary method of slices was justified and used to calculate the safety factor. Recommendations on the use of draglines available in Ukraine for forming the high single-tier dumps of overburden rock have been issued.

PL

W artykule rozważono kwestię powstawania nadkładu skalnego podczas eksploatacji złóż rudy żelaza na Ukrainie. Przeprowadzono analizę technologii formowania zwałowiska wysokiego jednopoziomowego w nieczynnym wykopie głębokim. Rozważane są dwa warianty technologiczne: załadunek skały na zboczu wysokiego zwałowiska jednopoziomowego oraz na jego krawędzi. Określono wpływ zależności skały obciążającej od krawędzi zwałowiska wysokiego jednopoziomowego na jego stateczność. Ustalono charakter zmiany szerokości ewentualnego graniastosłupa osuwiskowego oraz bezpieczną odległość położenia liny zgarniającej. Możliwości powstania wysokiego zwałowiska jednopoziomowego w reżimie kontrolowanych deformacji są uzasadnione. Dla wysokiego zrzutu jednopoziomowego zasadna była zwykła metoda przekrojów, wykorzystana do obliczenia współczynnika bezpieczeństwa. Wydano zalecenia dotyczące wykorzystania dostępnych na Ukrainie koparek do formowania wysokich jednopoziomowych zwałów nadkładu.

13

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.

14

Slope stability analysis of post-mining dumps with the use of photogrammetric geometry measurements - a case study

Wróblewska Magdalena, Kowalska Magdalena, Łupieżowiec Marian

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

171--185

EN

Post-mining dumps are a common sight in the industrial areas of Silesia (Poland). Despite several reclamation projects, many of them still constitute an unresolved problem. It is not only a matter of unaesthetic view - they often pose a threat to the environment and the people living nearby. Despite revitalization, some dumps are not properly maintained and are at the risk of slope failure. Such places require constant geodetic observation and stability control. In this article, the example of a dump located in the city of Gliwice was used to show the possibilities offered by the use of photogrammetry and unmanned aerial vehicles (UAV) for cyclic checks of the embankment condition. The current state of the dump and the results of interventions after two incidents of slope failure, were observed. The main slopes of the terrain surface and at the selected cross-sections were determined in two flight missions. The obtained geometrical data were used in the further numerical analysis. Finite Element Method model representing one of the escarpment cross-sections was built to estimate the factor of safety and determine the main mechanisms responsible for the failure. Elastic-perfectly plastic Coulomb-Mohr model was used to describe the behaviour of the minestone and the ‘c - tan φ reduction’ - for calculation of the stability. The problem of reliable material properties’ estimation was emphasized. The analysis included the impact of seepage and total head difference on the slope stability. It was concluded that the rainfall intensity had a decisive influence on the instability of the dump.

PL

Hałdy pokopalniane nadal stanowią typowy element w krajobrazie Górnego Śląska. Wiele z nich nie jest już użytkowana przez kopalnie węgla kamiennego jako miejsce składowania odpadów; została poddana procesom rekultywacji i przeznaczona na tereny inwestycyjne. Na takim obszarze mieści się np. katowicki „Spodek” czy Wojewódzki Park Kultury i Wypoczynku w Chorzowie. Często tereny te nie są jednak właściwie zabezpieczone i mimo rewitalizacji, niektóre nasypy mogą stanowić zagrożenie dla mieszkańców i środowiska. Przykładem takiego problemu jest hałda przy ulicy Pszczyńskiej w Gliwicach, będąca pozostałością po kopalni węgla kamiennego, która zakończyła wydobycie w tym rejonie ponad 20 lat temu. Na długości ok 600 metrów skarpa o wysokości ok. 8 m sąsiaduje bezpośrednio z ruchliwą drogą. Wielokrotnie, zwykle po ulewnych opadach deszczu, następowały na tym obszarze osuwiska skutkujące zamknięciem znacznego odcinka drogi dla ruchu kołowego. Tego typu miejsca wymagają stałej obserwacji geodezyjnej i kontroli stateczności. W wielu przypadkach trudno jest ustalić właściciela hałdy, przez co wejście w teren w celu wykonania klasycznych pomiarów geodezyjnych jest utrudnione. Dodatkowo z uwagi na często strome i wysokie skarpy, wykonywanie pomiarów klasycznych może stanowić zagrożenie dla osób mierzących. Wówczas przydatne stają się techniki zdalne, takie jak wykorzystanie bezzałogowego statku powietrznego (BSP, potocznie: „dron”). Wyniki pomiarów mogą być następnie wykorzystane w analizach numerycznych dotyczących stateczności skarp. Problematyczne oczywiście pozostaje ustalenie wartości parametrów modeli konstytutywnych reprezentujących materiał budujący hałdę. W niniejszym artykule na przykładzie hałdy zlokalizowanej na terenie miasta Gliwice pokazano możliwości, jakie daje wykorzystanie fotogrametrii oraz bezzałogowych statków powietrznych (BSP) do cyklicznych kontroli stanu nasypów. Obserwowano aktualny stan zwałowiska oraz efekty naprawy po dwóch przypadkach awarii skarpy. Podczas dwóch misji lotniczych wyznaczono główne spadki powierzchni terenu oraz wybrane przekroje poprzeczne. Uzyskane dane geometryczne wykorzystano w dalszej analizie numerycznej. Zdefiniowano model z wykorzystaniem Metody Elementów Skończonych, reprezentujący jeden z przekrojów skarpy w celu oszacowania współczynnika bezpieczeństwa oraz określenia głównych mechanizmów odpowiedzialnych za awarię. Do opisu zachowania ośrodka gruntowego wykorzystano sprężysto-idealnie plastyczny model Coulomba-Mohra, a w analizie stateczności użyto metody redukcji wytrzymałości „c - tan φ”. Zwrócono uwagę na problem wiarygodnego oszacowania właściwości materiałów. W analizie uwzględniono wpływ ciśnienia spływowego i różnicy naporów na stateczność skarpy. Stwierdzono, że decydujący wpływ na niestabilność zwałowiska miała intensywność opadów deszczu.

15

Slope stability analysis under rainfall infiltration condition using the minimum potential energy method

Fang Weihua, You Rongqiang, Hou Hui, Sun Jiaping, Yu Tiantang

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e117, 2023

EN

Rainfall infiltration is a key factor to induce landslides, and it is important to study the rule of rainfall infiltration on slopes for the prediction and prevention of landslides. This paper combines the minimum potential energy method with the existing analytical solution of seepage field, and proposes a new method for unsaturated soil slopes under rainfall conditions. Specifically, the total potential energy function of the unsaturated soil slope is established by considering the real-time changes in system potential energy caused by rainfall infiltration. Additionally, the effects of rainfall infiltration on the shear strength of the soil, the self-weight of sliding mass and the seepage force are considered. The ratio of the slip resistance moment to the sliding moment is defined as the safety factor (SF) of the slope. The real-time evaluation of the stability of unsaturated soil slopes is realized during rainfall. The research results show that the results obtained by the proposed method are closer to the reference solutions. Meanwhile, the rules of rainfall intensity as well as slope angle on slope stability are conducted. Finally, the relationship between the sliding depth of failure surface and rainfall is also studied.

16

An extended 3D limit analysis of slope stability considering prestressed anchor cables reinforcement

Hong Yong, Shao Zhushan, Wu Kui, Shi Guangbin, Wu Saisai, Jiang Song

Archives of Civil and Mechanical Engineering

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2023

|

Vol. 23, no. 1

art. no. e59, 2023

EN

Prestressed anchor cables have been extensively utilized in slope reinforcement engineering. Combining limit analysis with the strength reduction method (SRM), this article presents a new method to assess the three-dimensional (3D) stability of slopes with prestressed anchor cables. Compared with traditional methods, the factor of safety (FS) calculation method is modified by considering prestressed anchor cable reinforcement by applying a horn-like shape 3D rotational failure mechanism. To validate the proposed method, comparisons between unreinforced slopes and those reinforced with a row of anchor cables are carried out using optimization algorithms and procedures. The minimum width-to-height (B/H) ratio for which the slope can be analyzed using two-dimensional (2D) analysis under different FS calculation accuracies is obtained. To evaluate the consequences of the model parameters, parametric analysis is performed, assessing the FS sensitivity, 3D effects, anchor cable axial force, anchor position, anchor orientation, slope angle, internal friction angle, and cohesion on slope stability. Additionally, slope stabilities under the reinforcement of a row and multiple rows of anchor cables are compared and analyzed. The proposed approach can guide the design and evaluation of slope reinforcement with prestressed anchor cables.

17

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.

18

Reviews on Finite Element Modeling Practices of Stone Columns for Soft Soil Stabilization Beneath an Embankment Dam

Teshager Daniel Kefelegn, Belayneh Henok Lemma

Studia Geotechnica et Mechanica

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2022

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Vol. 44, nr 4

343--353

EN

This article reviews the numerical approach in stone column practices and presents the benefits of stone columns as a ground improvement of soft soil to support an embankment dam. In this article, the methodological approaches to numerically modeling stone columns in both 2D and 3D studies, as well as the selection of an appropriate constitutive model are discussed. The numerical practices for the installation of the stone column and the validation procedures used to ensure the accuracy of the numerical analysis are also explained. In addition to that, the study also presents the benefits of stone columns in improving settlement behavior, slope stability, and decreasing the end time of consolidation. Parameters that influence the performance of the stone column with their respective results are also assessed.

19

Parametric study of the earth dam's behaviour subjected to earthquake

Ayeche H., Zitouni Z., Limam A., Bouafia A.

Studia Geotechnica et Mechanica

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2022

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Vol. 44, nr 4

267--281

EN

Static stability of an earth dam can be established by estimating the static safety factor equal to the ratio of the shear strength to the shear stress along a critical sliding area. In contrast, it is more complicated to evaluate the dynamic stability during an earthquake. The water filling the interstices of the earth dams cannot drain during the short duration of an earthquake. An excess pore water pressure DU develops, and its role is predominant in the destabilisation of the dam. The pore water increase causes a decrease in the soil shear strength. It is, therefore, crucial to evaluate and take into consideration DU in the dam dynamic stability analysis. This research is a contribution to reach this objective. A parametric study was conducted by varying the physical and mechanical soil characteristics constituting the dam, as well as its geometrical values, in order to evaluate their effects on the dynamic safety factor. The dynamic safety factor is calculated using the pseudo-static method, taking into account the excess pore water pressure that develops during cyclic loading into the granular soil of the earth dam upstream face. The results of the parametrical analytical study were also compared to the results of numerical simulations of the dam seismic stability trough pseudo-static method. The numerical simulations were done with three different software: PLAXIS and ABAQUS (based on the finite element method) and GEOSTAB (deals with the problem at the limit equilibrium using the simplified Bishop method). At the end, on one hand, we were able to describe how and at what level of the dam upstream face the sliding occurs, and on the other hand, we were able to underline the adequate combination between the dam geometric parameters and the mechanical soil characteristics which may ensure seismic stability.

20

Importance of seismic wave frequency in FEM-based dynamic stress and displacement calculations of the earth slope

Fuławka Krzysztof, Kwietniak Anna, Lay Vera, Jaśkiewicz-Proć Izabela

Studia Geotechnica et Mechanica

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2022

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Vol. 44, nr 1

82--96

EN

Reliable assessment of earthen dams' stability and tailing storage facilities widely used in the mining industry is challenging, particularly under seismic load conditions. In this paper, we propose to take into account the effect of the dominant frequency of seismic load on the stability assessment of tailing/earthen dams. The calculations are performed by finite element modelling (FEM) with the Mohr–Coulomb failure criteria. To separate the frequency content from other dynamic parameters describing the seismic wave, synthetic waveforms with identical amplitude and attenuation characteristics, but differing spectral characteristics have been used. The analysis has been performed for three different slope angles and two scenarios of seismic wave propagation. Consequently, the changes of total displacement and shear stresses depending on the frequencies have been determined and clearly show that lower frequencies cause higher stress levels and displacement. Finally, the response surface methodology has been applied to determine how different parameters affect the slope stability under dynamic load conditions. Overall, this study is a first step to improve the existing methods to assess slope stability when considering seismic load.