Suitable Slope Research Articles

Application of Haines and Terbrugge chart for suitable slope angles – A case study of Artisanal and small-scale mining

Application of Haines and Terbrugge chart for suitable slope angles – A case study of Artisanal and small-scale mining

Modeling spatial variability of mechanical parameters of layered rock masses and its application in slope optimization at the open-pit mine

Mining engineering with layered structures often obtains extensive geological data to ensure reliability of mining operations. Effectively utilizing these data to characterize the spatial distribution of mechanical parameters in layered rock mass is crucial for slope stability analysis. This study focuses on the Heishan open-pit mine as a case study, leveraging the distinctive characteristics of mining engineering geological data. A three-dimensional fracture network was then generated based on the distribution of fractures in the rocks, and the representative elementary volume of the rock mass was determined by calculating the volumetric joint count (Jv). Statistical characteristics of various geological data are analyzed, and a geological statistical method combining the Kriging method and inverse distance power method is applied to establish a spatial distribution block model for geological strength index (GSI) and rock mechanical properties. Subsequently, a spatial variability model of the mechanical parameters of the layered rock mass was generated based on the Hoek–Brown criterion. Furthermore, the heterogeneous mechanical model is implemented in numerical software for stability analysis and slope angle optimization. The findings indicate that each engineering zone of layered slopes exhibits unique mechanical parameters while demonstrating significant layered distribution patterns at a macro level. Considering spatial variability, the mechanical model significantly impacts slope stability and slope angle optimization outcomes. Our research methodology facilitates accurate quantification of the heterogeneity of mechanical parameters in layered slopes without incurring excessive additional survey costs, enabling more rational explanations of slope landslides and the provision of suitable slope angle optimization designs.

Multifractal Characteristics and Displacement Prediction of Deformation on Tunnel Portal Slope of Shallow Buried Tunnel Adjacent to Important Structures

The tunnel portal section is often in extremely weak and fragmented strata, and the deformation of the portal side and slope will affect the stability of the surrounding rock and the tunnel-supporting structure. However, the deformation characteristics and displacement development patterns of slopes in the tunnel portal section are not clear. In this paper, the multifractal characteristics and displacement prediction of the deformation sequence of the tunnel portal slope at of a weak and water-rich shallow buried tunnel adjacent to an important structure are studied in depth. Combined with the deformation characteristics of the tunnel portal slope, a suitable slope monitoring and measurement scheme is designed to analyze the deformation pattern of the tunnel portal slope. Based on the multifractal detrended fluctuation analysis (MF-DFA) method, the multifractal characteristics of the deformation monitoring sequences at each monitoring point of the tunnel portal slope are analyzed. The multifractal characteristics of displacement sequences at different monitoring points of the tunnel portal slope are consistent with the actual monitoring results. Furthermore, the Long Short-Term Memory (LSTM) model is optimized using the Particle Swarm Optimization (PSO) algorithm to predict the deformation of the tunnel portal slope. The results show that the maximum mean square error (MSE) of the horizontal displacement test set prediction results is 0.142, and the coefficient of determination (R2) is higher than 91%. The maximum value of MSE for vertical displacement test set prediction is 0.069, and the R2 are higher than 91%. The study shows that the performance of the PSO-LSTM prediction model can meet the requirements for predicting the displacement of the tunnel portal slope. Based on the MF-DFA method and PSO-LSTM prediction model, the fluctuation characteristics of the displacement value of the tunnel portal section can be accurately identified and the displacement development pattern can be effectively predicted. The conclusions of the study are of great practical significance for the safe construction of the tunnel portal section.

A GIS-based catastrophe approach for optimal site selection for installation of solar power plants, East Azerbaijan province case study, Iran.

Due to depletion of fossil fuels and environmental issues, renewable energy consumption is increasingly growing. Solar energy as the most abundant renewable energy source available is becoming more popular around the world. In the current study, the optimal sites for solar photovoltaic power plants in East Azerbaijan province, Northwest Iran, were investigated. A total of 17 variables were categorized into four groups: climatic, geomorphological, environmental, and access-economic. In order to integrate the variables, a model based on catastrophe theory in the context of GIS was applied. The relative importance and weight of the criteria are computed based on the internal mechanism of the catastrophic system, thus greatly reducing subjectivism and uncertainties of the decision-making process. Five optimal sites located in the western part of the province within the counties of Malekan, Bonab, Ajabshir, Shabestar, and Tabriz were identified as suitable sites for the construction of solar photovoltaic power plants, where there are ideal conditions in terms of many environmental-human variables such as high potential of solar energy, high sunshine hours, low relative humidity, suitable slope, poor vegetation, distance to protected areas, proximity to the population centers, excellent access to the roads and to the main power lines.

Stability Analysis of Slope Using Displacement Criteria of Soil on The Shear Plane

Slope failure can harm structures and endanger lives due to a variety of circumstances. Landslides are such slope failures that are of abrupt, discontinuous, and complex in nature. Adopting suitable slope failure prediction tools is crucial in preventing such catastrophic failures. Conventional methods such as limit equilibrium methods applicability in stability analysis of slopes has become limited due to various limitations. The present study is to understand the slope failure mechanism using a mathematical strategy that simulates actual field conditions. Based on soil properties like the shear modulus of the soil and geometrical characteristics of the slope at failure, mathematical formulations have been developed to assess the stability of slopes. All these parameters are greatly affected by the soil mass displacement on the shearing plane at failure. The current approach demonstrates the critical safety factor, which may be more than 1, but still a threshold value where the conventional methods are lacking. The parametric analysis was conducted to ascertain the impact of displacement on crucial slope safety factors as well as for various soil parameters along the slope’s failure plane.

SOCIAL COST - BENEFIT ANALYSIS OF ACTIVE MOBILITY PROJECTS IN CONTEXTS WITH STEEP TERRAIN. A CASE STUDY IN COLOMBIA

Active mobility projects can potentially initiate paradigm shifts in population and urban planning decision-makers. This paper aims to conduct a social cost-benefit analysis of an active mobility project in a Colombian city. The increase of physical activity, reduction of CO2 emissions, and traffic crashes were measured in an area with suitable slopes to promote bicycles for commuting. A social cost-benefit ratio of 1.14 was found, with physical activity and road safety as the most important outcomes of the active mobility infrastructure. Furthermore, a big room for the increase and promotion of cycling as a mode of transport is addressed.

A statistical assessment of the fatigue strength improvement of butt-welded joints by flush grinding

All major rules and guidelines include fatigue design (FAT) classes for flush ground butt-welded joints. These FAT classes vary between FAT110 and FAT155; however, in the majority of cases, the underlying database and specimen-related details are unclear or unknown. This study evaluates 1003 fatigue test results gathered from various literature sources and tries to relate the fatigue strength improvement to typical specimen types and test conditions. To this goal, statistical methods based on correlation analysis are employed. Next, proposals for updates of rules and guidelines for flush ground butt-welded joints made of steel are established by determining new FAT classes and a suitable slope exponent. In addition, an overview of design standards and recommendations is given and main influencing factors are discussed.

Application of the deterministic block theory to the slope stability design of an open-pit mine in Morocco

Purpose. Discontinuities in rock masses are natural fractures that delimit various block shapes and sizes, which can fall, slide or topple from the excavation and collapse under their own weight inducing probably severe damage. Thus, it is essential to carry out a block analysis before beginning any surface or underground excavation project. This paper proposes a methodology based on key block theory analysis to select the suitable slope of different discontinuous rock masses of an open-pit mine in Morocco. Methods. At first, the main discontinuities of each bench are determined and projected onto a stereonet with a maximum dip angle of the excavation plane. Then, it is possible to identify the removable blocks by using the theorem of removability according to block theory. After that, a limit equilibrium analysis is performed to determine the failure mode and the friction angle required to stabilize the blocks. When the selected dip angle of the slope plane is found to be unsuitable, it is changed and reduced by one degree, and the same approach is repeated until the maximum safe slope dip angle is obtained. Findings. The results of the proposed methodology based on key block theory analysis have shown that the maximum safe slope angles of the studied benches are in the range of 63-73°. When compared to the slope angles used in the mine, which are between 58-78°, the results of this study are close to in-situ conditions. Originality. In this research, the maximum safe slope angle of fractured rock masses was optimized by eliminating slope angles inducing unstable blocks (key blocks) and by using the stereographic projection method of key block theory. Practical implications. Using this methodology, stability of rock slopes in civil or mining-engineering projects can be designed or assessed when geotechnical data are very limited.

ANALISIS DEFORMASI DAN STABILITAS LERENG DENGAN VARIASI GEOMETRI DAN PERKUATAN GEOTEKSTIL PADA PROYEK GEDUNG FAKULTAS HUKUM UII

Indonesian Islamic University (UII) is a private university located in Sleman, Special Region of Yogyakarta. As an educational institution, UII must be able to fulfill the infrastructure to carry out the teaching and learning process for its students, namely the lecture building. At present UII has campuses spread across Kaliurang (integrated campus), Condongcatur (Faculty of Economics), and student parks (Faculty of Law). The process of building a law faculty building UII is on the road Kaliurang km14.5 which is just below the foot of Mount Merapi and has contours of mountainous land. The contours of mountainous land have different levels of land up and down. In mountainous areas can cause problems, namely landslides. In the construction of the UII law faculties building, a suitable slope design is needed, so to solve the problem, slope stability analysis is used. This method is carried out by analyzing the deformation and slope stability by strengthening the geotextiles using the Plaxis 8.2 program. Slope modeling is designed with variations in geometry and variations in water level. Geometry variations used are geometry 70 °, 60 °, and 50 ° while variations in water level with dry water conditions, depth of water conditions 3.8 m, and saturated water conditions. In carrying out the analysis using structural loads and earthquake loads. Deformation analysis is seen from horizontal point X deformation, vertical point X deformation and horizontal deformation of Y-Y pieces. The results of this study are that slope with geotextile reinforcement have large safety factor and small deformations. A more slope geometry variation (50°) result in a larger safety factor and has a small deformation than steep geometry (70°). Groundwater variation have an influence on the results of the safety factor and deformation. The face of saturated ground water has a low safe value and large deformation due to having more water content.

Failure investigation and treatments of tunnel entrance collapse in weak diatomaceous soil induced by heavy rainfall through coupling surface and groundwater flows

Rainfall is a great threat to the stabilities of the slope at tunnel entrances located in mountainous areas because it can reduce the shear strength of soil and, as a result, the stabilities of tunnel entrances. Although conventional rainfall-induced slope damage analyses commonly overlook the impact of runoff, it is crucial to consider it to assess slope instability accurately. To assess the factor of safety distribution about the slope of the Feifengshan Tunnel in Zhejiang Province, China, and analyze the impact of runoff on slope instabilities, this paper uses a coupling model of surface runoff, groundwater flow, as well as soil mechanics, through the shallow water equation, Richards equation, and the local safety factor (LFS) method. Furthermore, given the strain-softening characteristics of diatomaceous soil, designing and analyzing them according to peak strength may result in potential hazards. Thus, this study analyzes the distribution of the slope safety factor under different constitutive models and recommends suitable slope reinforcement measures. The study also investigates the slope reinforcement measures required to avoid the secondary collapse of tunnel entrance during rainfall, verifying numerical simulation results regarding the section’s volumetric water content and surface settlement values. The findings of this study offer a dependable approach for evaluating the stability of tunnel entrance slopes and are significant for tunnel site selection and reinforcement effect assessment. The numerical results emphasize the effects of surface runoff from rainfall water distribution. Furthermore, the strain softening model has significant advantages in calculating surface settlement and tunnel slope failure.

Machine Learning Approaches for Slope Deformation Prediction Based on Monitored Time-Series Displacement Data: A Comparative Investigation

Slope deformation prediction is one of the critical factors in the early warning of slope failure. Establishing an accurate slope deformation prediction model is important. Time-series displacement data of slopes directly reflect the deformation characteristics and stability properties of slopes. The use of existing data analysis approaches, such as statistical methods and machine learning algorithms, to establish a reasonable and accurate prediction model based on the monitored time-series displacement data is a common solution to slope deformation prediction. In this paper, we conduct a comparative investigation of machine learning approaches for slope deformation prediction based on monitored time-series displacement data. First, we established eleven slope deformation prediction models based on the time-series displacement data obtained from seven in situ monitoring points of the Huanglianshu landslide using machine learning approaches. Second, four evaluation metrics were used to comparatively analyze the prediction performance of all models at each monitoring point. The experimental results of the Huanglianshu landslide indicated that the long-short-term memory (LSTM) model with an attention mechanism and the transformer model achieved the highest prediction accuracy. The comparative analysis of model characteristics suggested that the Transformer model is better adapted to predict nonlinear landslide displacements that are affected by multiple factors. The drawn conclusion could help select a suitable slope deformation model for early landslide warnings.

PEMILIHAN KELURAHAN CALON LOKASI TPU DI JAKARTA

DKI Jakarta experienced a public cemetery (TPU) land crisis during covid-19 which caused 3 (three) overcapacity TPU lands (DKI Jakarta Provincial Government, 2021). The need for TPU is increasing, causing problems such as a shortage of grave land. In overcoming this problem, a plan for selecting a new TPU location is needed, considering the land crisis can be minimized and the community's need for public burial places is still met. The DKI Jakarta Spatial Planning & Zoning Pattern designates 97 sub-districts to become TPU land developments. In choosing the location of the new TPU, a structured research method is needed, so that among these 97 sub-districts the best location can be chosen, in selecting the right location by using the map overlay analysis method (arcGIS). The stages of selecting the location of the new TPU use criteria, namely, the use of vacant land, the slope of the slope, the radius of the settlement which will be tested simultaneously in 97 urban villages. The results of this study selected 3 sub-districts to be the location of the new TPU, namely Rorotan, Grinding and Rawa Terate Villages. This selected sub-district has an area of +10 ha of vacant land, has a minimum radius of 500m from the settlement and a suitable slope

Bound-Preserving Discontinuous Galerkin Methods with Modified Patankar Time Integrations for Chemical Reacting Flows

In this paper, we develop bound-preserving discontinuous Galerkin (DG) methods for chemical reactive flows. There are several difficulties in constructing suitable numerical schemes. First of all, the density and internal energy are positive, and the mass fraction of each species is between 0 and 1. Second, due to the rapid reaction rate, the system may contain stiff sources, and the strong-stability-preserving explicit Runge-Kutta method may result in limited time-step sizes. To obtain physically relevant numerical approximations, we apply the bound-preserving technique to the DG methods. Though traditional positivity-preserving techniques can successfully yield positive density, internal energy, and mass fractions, they may not enforce the upper bound 1 of the mass fractions. To solve this problem, we need to (i) make sure the numerical fluxes in the equations of the mass fractions are consistent with that in the equation of the density; (ii) choose conservative time integrations, such that the summation of the mass fractions is preserved. With the above two conditions, the positive mass fractions have summation 1, and then, they are all between 0 and 1. For time discretization, we apply the modified Runge-Kutta/multi-step Patankar methods, which are explicit for the flux while implicit for the source. Such methods can handle stiff sources with relatively large time steps, preserve the positivity of the target variables, and keep the summation of the mass fractions to be 1. Finally, it is not straightforward to combine the bound-preserving DG methods and the Patankar time integrations. The positivity-preserving technique for DG methods requires positive numerical approximations at the cell interfaces, while Patankar methods can keep the positivity of the pre-selected point values of the target variables. To match the degree of freedom, we use $$Q^k$$ polynomials on rectangular meshes for problems in two space dimensions. To evolve in time, we first read the polynomials at the Gaussian points. Then, suitable slope limiters can be applied to enforce the positivity of the solutions at those points, which can be preserved by the Patankar methods, leading to positive updated numerical cell averages. In addition, we use another slope limiter to get positive solutions used for the bound-preserving technique for the flux. Numerical examples are given to demonstrate the good performance of the proposed schemes.

A Scenario Simulation Study on the Impact of Urban Expansion on Terrestrial Carbon Storage in the Yangtze River Delta, China

Assessing the impacts and drivers of urban expansion on terrestrial carbon storage (TCS) is important for urban ecology and sustainability; however, a unified accounting standard for carbon intensity and research on the drivers and economic value of TCS changes are lacking. Here, urban expansion and TCS in the Yangtze River Delta were simulated based on Patch-generating Land Use Simulation and Integrated Valuation of Ecosystem Services and Trade-offs models; scenario simulation; Literature, Correction, Ratio, Verification carbon intensity measurement; and land use transfer matrix methods. The results showed that (1) from 2000 to 2020, urbanization and TCS loss accelerated, with 61.127% of TCS loss occurring in soil, and land conversion was prominent in riverine and coastal cities, mainly driven by the urban land occupation of cropland around suitable slopes, transportation arteries, and rivers. (2) From 2020 to 2030, urban land expansion and TCS loss varied under different scenarios; economic losses from the loss of the carbon sink value under cropland protection and ecological protection were USD 102.368 and 287.266 million lower, respectively, than under the baseline scenario. Even if urban expansion slows, the loss of TCS under global warming cannot be ignored. Considering the indirect impacts of urbanization, the failure to establish a regional development master plan based on ecosystem services may affect China’s carbon targets.

Finite Element Modeling of Geotextile Reinforced Embankments on Soft Clay

The use of geotextiles as a reinforcement material for improving the factor of safety against slope failure in embankments built on soft clay is becoming a common practice. This work is intended to help understand the effect of the geotextile reinforcement has on such embankments and to provide a design aid for civil engineers that enables them to quickly estimate the factor of safety against slope failure. Seventy four different cases were modelled and analyzed using a finite element software, GeoStudio 2018 R2. The results showed that the optimum improvement was achieved when using a single layer of geotextile reinforcement placed at the base of the embankment, by which the factor of safety increased by up to 40%. Adding a second layer, a third layer and a fourth layer, increases the safety factor by 2.5%, 1% and 0.5% respectively. Different charts for different heights of embankments were presented to aid in finding the most suitable slope angle and number of reinforcement layers required to achieve a certain safety factor.

Investigations of Unsaturated Slopes Subjected to Rainfall Infiltration Using Numerical Approaches—A Parametric Study and Comparative Review

In the past 30 years, research on rainfall-induced landslides has grown remarkably. The contribution of matric suction to soil strength and the physics of water flow in unsaturated soils are widely accepted phenomena among researchers. However, the adoption of unsaturated soil mechanics in geotechnical engineering practice has been relatively slow, in part due to the practicality of design solutions available to the engineer. This paper conducts a parametric study on unsaturated silty slopes under a vertical steady flow rate to identify the suitable slope and hydrologic conditions to incorporate unsaturated conditions for preliminary stability analysis. Notably, the contribution of suction is most significant for silt/clay slopes with a water table located below the mid-height of the slope. For slopes with slope height ≥20 m and a fairly high water table, the slope height is a primary controlling factor of slope stability. Two case studies based on distinct failure mechanisms are presented to review the application of common geotechnical software in rainfall seepage and stability analyses of unsaturated slopes. Focus is placed on the pre-failure and failure stages of each case study. The slip surface search method, failure mode, and coupling approach integrated into each computer program caused notable differences in output results.

Employment of Continuous Slope Cumulative Frequency Spectrum in geomorphology quantitative analysis – a case study on Loess Plateau

Slope spectrum is an effective methodology of digital terrain analysis in geomorphology. However, some limitations are still encountered in the construction of the slope spectrum. E.g., the uncertainties caused by slope classification and resolution of digital elevation model (DEM) may restrict the development of slope spectrum and cause a certain spatial information loss. In this paper, a new spectrum method, defined as continuous slope cumulative frequency (CSCF) spectrum, is proposed. Compared with the slope spectrum, the CSCF spectrum does not require slope classification and combines the spatial information of all grids. Hence, it possesses richer terrain feature information and minimal spatial information loss. Meanwhile, it is more convenient to be used in different study areas without requiring heavy work of slope spectrum in determining the suitable slope classification. We also found that the CSCF spectrum can be generally extracted from DEM with different resolutions, whereas the slope spectrum cannot. Experiment results show that the CSCF spectrum is an efficient geomorphology quantitative analysis method that can quantitatively depict the spatial distribution and evolution process of the typical loess landforms from different angles. Besides, the CSCF spectrum can accurately deduce the stable slope spectrum, whereas the slope spectrum cannot deduce the CSCF spectrum, which further suggests that the previous studies in slope spectrum can be conducted on the basis of the CSCF spectrum. Furthermore, the CSCF spectrum shows well application potentials in landform classification with comparative performance to previous methods. Overall, the CSCF spectrum is an effective method in geomorphology quantitative analysis. Considering that the CSCF spectrum solves two key deficiencies in the present model of slope spectrum (slope classification and DEM resolution) and extends the application scope and concept of spectrum method, it is promising to be the research paradigm of the spectrum method in digital terrain analysis.

Modeling shallow landslides and root reinforcement: A review

Slope Stability Models (SSMs) are valuable tools used as decision support in land management to mitigate catastrophic effects caused by rainfall-induced shallow landslides. In particular, SSMs incorporating the presence and influence of vegetation allow for the evaluation of how trees influence relative slope stability and how forest management could ensure the root reinforcement effect in space and time. By implementing empirical knowledge about complex mechanical and hydrological processes, SSMs have been realized by employing different modeling approaches and methods, becoming suitable for different contexts and scales of analysis. Recent SSMs increasingly consider vegetation both as a mechanism to counteract the triggering process of shallow landslides and as a manageable and modifiable tool for mitigating hazards.This review aims to analyze the state-of-the-art of SSMs applicable to vegetated slope areas, investigating those that consider root reinforcement and some of the most cited SSMs in the literature that neglect this effect instead. After classification and exposition on the spatial and temporal dimension of the analysis, modeling approaches, and complexity, we discuss the identification of the most suitable Slope Stability Model (SSM) for individual applications considering four fundamental aspects: modeling approaches, the analysis scale, and purpose, and the output data. Although all SSMs allow for risk analysis by quantifying the factor of safety, only a few allow for an accurate assessment of how changes in vegetation structure, due to the occurrence of natural and human disturbances, also affect the stability of a studied area. Such information is critical to identifying land management criteria to preserve and enhance the protection effect.The improvement of data collection and measurement techniques to obtain parameters for stability analysis required the development of new SSMs able to exploit the improved detail of information, thus allowing for increasingly accurate analyses.

Texture of airport pavements in terms of their drainage efficiency

Abstract: Characteristics of the drainage of the surface movement area of airports, and more precisely the rapid drainage of water from the surface, is the main safety factor taken into account at the stage of designing, building, and maintaining the movement area and adjacent areas. Drainage of water from the pavement is a basic requirement and serves to reduce the thickness of the water layer on the surface. Adequate drainage is ensured primarily by surfaces with a suitable slope, both longitudinally and transversely (natural water drainage). On the other hand, dynamic drainage is achieved through the texture of the pavement. The paper presents the results of research on the texture of airport pavements and their analysis in relation to the current requirements. In the tests, apart from the currently used point measurement method, an innovative method of assessing anti-skid properties was used, which allowed for the simultaneous measurement of the friction coefficient µ and a new coefficient of continuous mean profile depth and CMPTD texture. The obtained results allowed us to present conclusions that when assessing the texture of airport pavements and thus designing structural solutions in terms of their drainage, it is reasonable to take into account the technology of its implementation (cement concrete or asphalt concrete). Keywords: Drainage of airport pavements; Texture of airport pavements; Safety of air operations

Bayesian selection of slope hydraulic model and identification of model parameters using monitoring data and subset simulation

Accurate prediction of pore water pressure responses in soils is critical for predicting stability of a slope when subjected to rainstorms. Slope hydraulic model and soil hydraulic parameters have been widely used in prediction of pore water pressure responses under rainfall infiltration, but establishing a suitable slope hydraulic model and accurately identifying its parameters for a specific slope are often challenging due to a lack of knowledge and site investigation data on the slope, particularly the subsurface conditions. In-situ monitoring data (e.g., time series of pore water pressure under rainfall infiltration) from a slope provide valuable information about subsurface conditions of the slope. This study proposes a probabilistic back analysis method, using Bayesian updating with subset simulation (BUSS) and slope monitoring data, to determine the most suitable slope hydraulic model from a group of candidate models with different settings (i.e., governing equations, boundary conditions, and initial conditions). The most probable soil hydraulic parameters (e.g., spatially variable soil properties used in the slope hydraulic model) are identified simultaneously in the proposed method. The most suitable slope hydraulic model significantly improves quantification of uncertainties in soil hydraulic parameters and prediction of pore water pressure responses in slopes during rainfalls.