Modelling the effect of Nature Based Solutions on slope instability

2020 ◽  
Author(s):  
Stefano Tinti ◽  
Glauco Gallotti ◽  
Thomas Zieher ◽  
Jan Pfeiffer ◽  
Filippo Zaniboni ◽  
...  
Keyword(s):  
Slope Stability ◽  
Land Use Planning ◽  
Groundwater Level ◽  
Numerical Models ◽  
Slope Instability ◽  
Seismic Load ◽  
Technical Parameters ◽  
Hydrological System ◽  
The Stability ◽  
Open Air Laboratories

<p>In the framework of the OPERANDUM (OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks) project, modelling the effect of the Nature Based Solutions (NBS) on selected open-air laboratories plays a determinant role. In this work, we focus the attention on the Vögelsberg (Tyrol, Austria) landslide case study, located in the municipality of Wattens. The 0.25 km<sup>2</sup> active part of the slope shows annual movement rates in the order of 3.5-6 cm/a. Recent studies provided evidence that the motion is mainly driven by variations of the groundwater level. The latter are related to prolonged moist periods during which excessive rainfall or snow melt water can infiltrate and act on the geo-hydrological system. With the aim of enhancing the slope stability employing NBS, a detailed analysis of the hydrogeology and the slope characteristics have been carried out, obtaining the required technical parameters describing the involved soil material. Furthermore, a slope stability analysis by means of different numerical models has been performed. Results prove that variations of the groundwater level in the range of 1-2 m can strongly affect the stability of the slope. Thus, specific NBS should aim at reducing the amount of infiltrating water. Examples of such NBS include the adaptation of forest management and land use planning, the introduction and re-activation of drainage channels and the sealing of leaky streams and channels. Beside the effects of the variation of the groundwater level, results have proved that the slope could fail under the action of a moderate seismic load. In this scenario, it is likely that the effects of the NBS would be insufficient to maintain the slope intact.</p>

scholarly journals Safety Assessment of Tunnel Portals for Site Selection Based on Spatial Information Geoprocessing

2019 ◽  
Vol 4 (4) ◽  
pp. 70
Author(s):  
Iau-Teh Wang
Keyword(s):  
Information Technology ◽  
Slope Stability ◽  
Site Selection ◽  
Spatial Information ◽  
Slope Instability ◽  
Geographical Information ◽  
Site Evaluation ◽  
The Stability ◽  
Slice Method ◽  
Spatial Information Technology

The evaluation of portal locations for mountain tunnels is among the most crucial considerations during route selection and structural layout planning. The development of spatial information technology has provided a more objective approach for assessing the slope stability of potential portal sites. The simulations in such studies have been performed to evaluate potential hazards and slope stability. However, potential instabilities resulting from excavation are seldom considered in these studies. Therefore, a method based on spatial information technology was developed in this study for considering the potential impact of the direction and depth of excavations on portal stability. An analysis method for an infinite slope was integrated into the geographical information system for evaluating the stability of critical wedges. The proposed method provides a reasonable estimation comparable with that provided by the conventional slice method. The results of applying this method to six mountain tunnel portals where slope instability occurred during construction indicate that the actual outcomes agreed with the predicted outcomes. For potential portal site evaluation, the proposed method facilitates the rapid estimation of safety factors for various slope designations, which is useful for site selection.

Comparing slope stability analysis using limit equilibrium and finite elements simulations of deep-seated landslides along the western margin of the Main Ethiopian Rift

2021 ◽  
Author(s):  
Tesfay Kiros Mebrahtu ◽  
Thomas Heinze ◽  
Stefan Wohnlich
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Strength Reduction ◽  
Ethiopian Rift ◽  
Seismic Load ◽  
Main Ethiopian Rift ◽  
Western Margin ◽  
The Stability

<p>Landslides and ground failures are among the common geo-environmental hazards in many of the tectonically active hilly and mountainous terrains of Ethiopia, such as in the western margin of the Main Ethiopian Rift in Debre Sina area. Besides the geological preconditioning, bi-modal monsoon and seismic events in the tectonically highly active region are usually suspected triggers. In order to minimize the damage caused by the slope failure events, a detailed investigation of landslide-prone areas using numerical modelling plays a crucial role. The aim of this study is to assess the stability of slopes, to understand the relevant failure mechanisms, and to evaluate and compare safety factors calculated by the different available numerical methods. The stability was assessed for slopes of complex geometry and heterogeneous material using the limit equilibrium method and the shear strength reduction method based on finite elements. Furthermore, numerical analysis was done under static and pseudo-static loading using the horizontal seismic coefficient to model their stability during a seismic event. The slope stability analysis indicates that the studied slopes are unstable, and any small scale disturbance will further reduce the factor of safety and probably causing failure. The critical strength reduction factors from the finite element method are significantly lower than the factor of safety from the limit equilibrium method in all studied scenarios, such as Bishop, Janbu Simplified, Spencer and Morgenstern-Price. The difference is especially evident for heterogeneous slopes with joints, which often are initiation points for the failure planes. The simulations show that slope stability of landslide prone hills in the study area strongly depends on the saturation conditions and the seismic load. The studied slopes are initially close to failure and increased pore-pressure or seismic load are very likely triggers.</p>

scholarly journals Groundwater Fluctuation Simulation in Pagelaran Landslide, Cianjur, Indonesia

2020 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Twin Hosea Widodo Kristyanto
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Groundwater Level ◽  
Slip Surface ◽  
Unit Weight ◽  
Undisturbed Soil ◽  
Actual Position ◽  
Groundwater Fluctuation ◽  
Artesian Wells ◽  
The Stability

Pagelaran is one of area in Southern Part of Cianjur. This area has high susceptibility of landslide. One of landslide in Pagelaran, which happened on December 2014, has destroyed 13 houses and damaged vital road along 200 m. A year later, it started to conduct observation regarding the slope. The research aimed to know the role of groundwater level fluctuation in Pagelaran Landslide. The geometry of slope and its slip surface were determined using Electrical Resistivity Tomography. The actual groundwater level was determined by measuring it from surrounding artesian wells. Parameters angle of friction, cohesion, and unit weight were obtained from laboratory tests toward undisturbed soil samples. These data were used for analyzing the actual slope stability condition. Then it was conducted the simulation of slope stability in accordance with fluctuations of groundwater level. The simulation was done by raising the groundwater level with range of 0.5 m. The results showed that the actual slope stability was in critical condition with the value of safety factor 1.044. It also showed that slope stability waned as rising of groundwater level. The value of safety factor was reduced by an average of 0.034 in each 0.5 m up of groundwater level until it became failure (FS<1) when the groundwater level was 0.95 m above the actual position. Therefore, it can be concluded that the position of groundwater level played a role toward the stability of slope in Pagelaran. The rising 0.5 m of groundwater level position will reduce the slope safety factor by 0.034. The slope will become failure if the position of groundwater level rises by 0.95 meter from the actual position. To prevent the rising of groundwater level in rainy season, which can trigger landslide, it can be attached pipes along the slope body to flow the groundwater through them.

scholarly journals The influence of climate effects and fluctuations in groundwater level on the stability of anthropogenic foothill slopes in the Krušné Hory Mountains, Czechia

Geografie ◽  
2010 ◽  
Vol 115 (4) ◽  
pp. 377-392 ◽  
Author(s):  
Jan Burda ◽  
Vít Vilímek
Keyword(s):  
Slope Stability ◽  
Groundwater Level ◽  
Climatic Factors ◽  
Open Pit ◽  
Quaternary Sediments ◽  
Climate Effects ◽  
The Stability ◽  
Krušné Hory Mountains

At the beginning of the 1980s, leveling circuits Z2b 11 and Z2b 3 (later also Z2b 12) were monitored as a means of confirming the hypothesis concerning the Krušné Hory Mountains uplift. Contemporary geodetical monitoring focuses on side slopes formed by Quaternary sediments and Tertiary clystones. The stability of these anthropogenic slopes is implicated by hillside inclination, geological and geomorphological settings as well as climatic factors. The main objective of this study is to geomorphologically interpret the geodetical monitoring of the ČSA open-pit mine’s hazardous side slopes and, in addition, to prove the influence of climatic factors on slope stability.

scholarly journals Evaluation of Slope Stability in an Urban Area as a Basis for Territorial Planning: A Case Study

2021 ◽  
Vol 11 (11) ◽  
pp. 5013
Author(s):  
Paúl Carrión-Mero ◽  
Josué Briones-Bitar ◽  
Fernando Morante-Carballo ◽  
David Stay-Coello ◽  
Roberto Blanco-Torrens ◽  
...  
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Land Use Planning ◽  
Background Information ◽  
Security Measures ◽  
High Susceptibility ◽  
Territorial Planning ◽  
The Stability ◽  
Definition Of ◽  
Very High

Slope stability is determined by pre-conditioning and triggering factors. The evaluation of the stability by scientific criteria provides crucial input into land-use planning and development. This work aimed to evaluate the slope stability of “Las Cabras” hill (Duran, Ecuador) through geological and geotechnical analysis and a susceptibility assessment that allowed the definition of areas potentially susceptible to landslide and detachment for land planning recommendations. The methodology included (i) analysis of background information about the study area; (ii) fieldwork, sampling and laboratory tests; (iii) assessment of susceptibility to landslides and detachment through a theoretical–practical evaluation (using suggestions by various authors); (iv) a safety factor assessment employing the simplified Bishop method; and (v) analysis of the relationship between susceptibility and stability. Sixteen geomechanical stations were evaluated. Of these, seven stations are characterised as category III (medium susceptibility), six stations as category IV (high susceptibility) and three stations as category V (very high susceptibility). According to the susceptibility zoning map, 58.09% of the total area (36.36 Ha) is in the high to very high susceptibility category. The stability analysis based on 16 critical profiles shows that three of these profiles have safety factor values of less than one (0.86, 0.82 and 0.76, respectively), and two profiles have values close to one (1.02 and 1.00). The northern area is conditioned mainly by a vertical slope with an outcrop of fractured and weathered sandstones, thereby favouring rockfall. The landslide vulnerability in the case of the southern zone is principally conditioned by the fact that the slope and dip are parallel. The described characterisation and susceptibility analysis provide a basis for security measures and territorial planning.

scholarly journals Effect of groundwater fluctuation, construction, and retaining system on slope stability of Avas Hill in Hungary

2021 ◽  
Vol 13 (1) ◽  
pp. 1139-1157
Author(s):  
Eslam M. Hemid ◽  
Tamás Kántor ◽  
Ahmed A. Tamma ◽  
Mostafa A. Masoud
Keyword(s):  
Slope Stability ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Slope Instability ◽  
Negative Effects ◽  
Destructive Effect ◽  
Groundwater Levels ◽  
Groundwater Level Fluctuations ◽  
The Church

Abstract Landslides are one of the natural hazards, which have significant negative effects on both humans and the environment. Thus, slope stability analyses and stabilization processes are necessary to obviate or mitigate landslides. In this study, the effect of groundwater level fluctuations and the construction of a building (i.e., a recently built church) on slope stability was investigated on the eastern slope of the Avas Hill, at Miskolc, in Northeast Hungary. Soil movements and groundwater levels were monitored and geological and slope stability models were constructed. Furthermore, the possibility of constructing a retaining system was evaluated to minimize the detrimental effects of both groundwater level fluctuations and the construction of the church. The findings showed that the fluctuation in groundwater levels had a destructive effect on slope stability due to pore-water pressure, which decreased the soil strength of the slope and slope stability. On the other hand, the church added an external load onto the underlying soil leading to an increase in slope instability. Hence, we suggested constructing retaining structures such as gravity retaining walls to increase the soil shear strength and enhance slope stability in the long term.

scholarly journals Slope Orientation and Vegetation Effects on Soil Thermo-Hydraulic Behavior. An Experimental Study

2020 ◽  
Vol 13 (1) ◽  
pp. 14
Author(s):  
Raül Oorthuis ◽  
Jean Vaunat ◽  
Marcel Hürlimann ◽  
Antonio Lloret ◽  
José Moya ◽  
...  
Keyword(s):  
Slope Stability ◽  
Land Use Planning ◽  
Complex Problem ◽  
Mitigation Strategies ◽  
Soil Conditions ◽  
Planning Strategy ◽  
The North ◽  
Develop Land ◽  
Drying Rates ◽  
The Stability

The stability and erosion of natural and man-made slopes is influenced by soil-vegetation-atmosphere interactions and the thermo-hydro-mechanical slope conditions. Understanding such interactions at the source of slope mass-wasting is important to develop land-use planning strategy and to promote environmentally adapted mitigation strategies, such as the use of vegetation to stabilize slopes and control erosion. Monitoring is essential for calibrating and validating models and for better comprehending the physical mechanisms of soil-vegetation-atmosphere interactions. We approached this complex problem by means of an experimental work in a full-scale monitored embankment, which is divided into four instrumented partitions. These partitions are North or South-faced and present a bare and vegetation cover at each orientation. Our main findings show that vegetation enhances rainfall infiltration and decreases runoff, which reduces slope stability and surficial erosion, while plant transpiration induces higher suctions and hence slope stability. Concerning thermal aspects, vegetation reduces the incidence of net solar radiation and consequently heat flux. Thus, daily temperature fluctuations and evaporation decreases. However, the effect of vegetation in the development of dryer soil conditions is more significant than the orientation effect, presenting higher drying rates and states at the North-vegetated slope compared to the South-bare slope.

scholarly journals Influence of Basalt Fiber-Reinforced Cement-Based Composite on Slope Stability

2021 ◽  
Vol 31 (2) ◽  
pp. 93-100
Author(s):  
Yiyun Yang
Keyword(s):  
Slope Stability ◽  
Limit Equilibrium ◽  
Basalt Fiber ◽  
Slope Instability ◽  
Strength Analysis ◽  
Design Calculation ◽  
Fiber Reinforced ◽  
Reinforced Cement ◽  
The Stability ◽  
The One

Slope instability may be caused by the action of external load or the lack of internal shear strength. The traditional limit equilibrium method cannot accurately calculate the safety coefficient of slopes enhanced by fiber-reinforced cement piles. Few scholars have discussed the anti-slip property, structural form, and design calculation of fiber-reinforced composite cement piles. Therefore, this paper chooses to analyze the influence of basalt fiber-reinforced cement-based composite (BFRCBC) on slope stability. On the one hand, the authors analyzed the anti-crack mechanism of BFRCBC: the strength analysis was carried out by the rule of mixtures, the anti-crack analysis was implemented by the fiber spacing theory, and the entire anti-crack process was discussed in details. On the other hand, the authors constructed a slope model, and performed the relevant stability analysis. Experimental results show that the BFRCBC cement piles can effectively enhance the stability of the slope.

scholarly journals Characteristics of Rainfall-Induced Slope Instability in Cisokan Region, Indonesia

2021 ◽  
Vol 53 (5) ◽  
pp. 210504
Author(s):  
Sugeng Krisnanto ◽  
Harianto Rahardjo
Keyword(s):  
Slope Stability ◽  
Pore Water ◽  
Groundwater Level ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Matric Suction ◽  
Slope Instability ◽  
Access Road ◽  
Level Increase ◽  
Long Access

A 25.5 km long access road has been constructed in a hilly area in Cisokan region. Several slope instabilities occurred during the rainy season, particularly at the end of heavy rainfall. A comprehensive study was performed to understand the characteristics of rainfall-induced slope instability. The study consisted of field observation, analyses of field and laboratory test data, and numerical analyses. The study revealed that in general there were two categories of slopes with instability characteristics: (i) slopes with a significant groundwater level increase during rainfall; (ii) slopes with an insignificant groundwater level increase during rainfall. In the first category, the slope instability was caused by a loss of matric suction and eventually the pore-water pressure, uw became positive as indicated by an increase of the groundwater level. In the second category, the slope instability was caused by a loss of matric suction without a rise in pore-water pressure, uw, to a positive magnitude. Two empirical curves of slope stability were developed as a preliminary guidance to assess slope stability during rainfall in the region.

The stability and collapse of lava domes: insight from UAS-derived 4D structure and slope stability models

2020 ◽  
Author(s):  
Brett Carr ◽  
Einat Lev ◽  
Loÿc Vanderkluysen ◽  
Danielle Moyer ◽  
Gayatri Marliyani ◽  
...  
Keyword(s):  
Slope Stability ◽  
Lava Domes ◽  
The Stability
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