Spatiotemporal regional modeling of rainfall-induced slope failure in Hulu Kelang, Malaysia

This study demonstrated the use of transient rainfall infiltration and grid-based regional slope stability analysis model incorporated with spatial rainfall distribution model for regional mapping of rainfall-induced slope failures in a slope failure-prone area in Malaysia, namely Hulu Kelang. Infinite slope analysis was incorporated into the improved model to compute the pore water pressure and slope stability of the region. Digital terrain maps, spatial rainfall distributions, soil profiles, groundwater table, and soil properties were input into the model. The results showed that the slope failures in the study area can be grouped into shallow failures (<4 m) and sub-shallow failures (4–8 m). Most of the shallow slope failures (<4 m) were triggered by the northeast monsoon while the NE monsoon that characterized by more prolonged and intense rainfalls. Spatial temporal distributions of shallow and sub shallow slope failures predicted using the improved model showed reasonably good comparison with the historical slope failure regions. Monsoon events have affected slope stability by reduction in matric suction, complete loss of matric suction, and development of positive pore water pressure (PWP). Computation for the effects of rainfall infiltration on PWP response and consequent effects on slope stability is enhanced by the spatial rainfall distribution model. The pore water pressure response to monsoon rainfall is a function of rainfall duration, the rate of infiltration, groundwater depth, soil thickness, and slope inclination. The amount of the local daily rainfall is not the only factor affecting slope stability. The prolonged antecedent rainfall could have a role to play in building up the slope failure mechanism

Discontinuous rock slope stability analysis under blocky structural sliding by fuzzy key-block analysis method

This study presents a fuzzy logical decision-making algorithm based on block theory to effectively determine discontinuous rock slope reliability under various wedge and planar slip scenarios. The algorithm was developed to provide rapid response operations without the need for extensive quantitative stability evaluations based on the rock slope sustainability ratio. The fuzzy key-block analysis method utilises a weighted rational decision (multi-criteria decision-making) function to prepare the 'degree of reliability (degree of stability-instability contingency)' for slopes as implemented through the Mathematica software package. The central and analyst core of the proposed algorithm is provided as based on discontinuity network geometrical uncertainties and hierarchical decision-making. This algorithm uses block theory principles to proceed to rock block classification, movable blocks and key-block identifications under ambiguous terms which investigates the sustainability ratio with accurate, quick and appropriate decisions especially for novice engineers in the context of discontinuous rock slope stability analysis. The method with very high precision and speed has particular matches with the existing procedures and has the potential to be utilised as a continuous decision-making system for discrete parameters and to minimise the need to apply common practises. In order to justify the algorithm, a number of discontinuous rock mass slopes were considered as examples. In addition, the SWedge, RocPlane softwares and expert assignments (25-member specialist team) were utilised for verification of the applied algorithm which led to a conclusion that the algorithm was successful in providing rational decision-making

Discontinuous rock slope stability analysis by limit equilibrium approaches - a review

Slope stability is one of the most important topics of engineering geology with a background of more than 300 years. So far, various stability assessment techniques have been developed which include a range of simple evaluations, planar failure, limit state criteria, limit equilibrium analysis, numerical methods, hybrid and high-order approaches which are implemented in two-dimensional (2D) and three-dimensional (3D) space. In the meantime, limit equilibrium methods due to their simplicity, short analysis time, coupled with probabilistic and statistics functions to estimate the safety factor (F.S), probable slip surface, application on different failure mechanisms, and varied geological conditions has been received special attention from researchers. The presented paper provides a review to limit equilibrium methods used for discontinuous rock slope stability analyses with different failure mechanisms of natural and cut slopes. The article attempted to provide a systematic review for rock slope stability analysis outlook based on limit equilibrium approaches

Application of the modified Q-slope classification system for sedimentary rock slope stability assessment in Iran

Abstract(#br)The Q-slope system is an empirical method for discontinuous rock slope engineering classification and assessment. It has been introduced recently to provide an initial prediction of rock slope stability assessment by applying simple assumptions which tend to reflect different failure mechanisms. This study offers a correlation relationship between Q-slope and slope stability degree using case studies of sedimentary rock slopes from 10 regions of Iran. To this end, we have investigated 200 areas from these regions, gathered the necessary geotechnical data, have classified the slopes from a Q-slope perspective, and have estimated their stability relationships. Based on artificial intelligence techniques including k-nearest neighbours, support vector machine, Gaussian process, Decision tree, Random-forest, Multilayer perceptron, AdaBoost, Naive Bayes and Quadratic discriminant analysis, the relationships and classifications were implemented and revised in the Python high-level programming language. According to the results of the controlled learning models, the Q-slope equation for Iran has indicated that the stability-instability class distributions are limited to two linear states. These limits refer to the B-Line (lower limit) as

Data on arsenic contamination in groundwater of Rafsanjan plain, Iran

This data article focuses on the arsenic in the groundwater of Rafsanjan plain in Kerman Province of Iran where the groundwater is being extensively used for drinking and irrigation of pistachio gardens. The measured arsenic concentrations range from 4 to 278 μg/L (with an average of 59 μg/L). About 85.3% of water samples have arsenic concentrations above 10 μg/L provided by the World Health Organization, WHO, guideline value. This data article provides also map showing the concentration of arsenic in groundwater of Rafsanjan area based on the situation of the sampling points in Rafsanjan region

Prioritization of Landslide Effective Factors and its Hazard Mapping Using Weighted Linear Combination method (case study: Vark watershed)

Landslide is a kind of natural disasters causing enormous human and financial losses every year in different countries. Identification and classification of landslide prone areas and their hazard zonation are of the most important steps in the assessment of environmental risks and play an indispensable role in watershed basins management. This study attempts to determine the relative risk of slope instability and landslide occurrence in the Vark area using Weighted Linear Combination (WLC) method. As the first step, In order to assess the stability of slopes, the occurred landslides in this area was recorded using the satellite images, Google Earth software and field observations. The impact of each factor on landslides such as slope, aspect, land use, elevation, lithology, earthquake intensity and distance from fault, road, spring, and drainage were defined in the Arc GIS software. The map of each factor was standardized and weighted using Fuzzy Logic and Analytic Hierarchy Process (AHP), respectively. Investigation of the factors affecting the risk of landslides in the basin of vark indicates tow factors including the slope and the lithology have the most important role in the occurrence of landslides in the area. According to the results of using the WLC in landslide risk zonation, 13.85, 26.90, 27.81, 21.90 and 9.52 percent of the area are located in very low, low, medium, high and very high-risk classes respectively. The investigation of the risk sensitive to the risk of landslides is located in parts of the north, north west and south west areas

Landslide susceptibility zoning in a catchment of Zagros Mountains using fuzzy logic and GIS

Landslide is one of the dangerous types of natural hazards. This phenomenon causes damages in many countries every year. A detailed landslide hazard assessment is necessary to reduce these damages. This research aims to map the landslide susceptibility zoning (LSZ) using the fuzzy logic method and GIS in the Sorkhab basin as a part of the Zagros fold and thrust belt (FTB), northwestern Iran. All slide types were recorded in fieldwork as landslide inventory. Based on the results, four types, i.e., debris slide, earth slide, and rock fall and complex of landslides, was identified in the region. Then, the effect of each landslide contributing factor including topographical elevation heights, slope classes, aspect classes, geological units, proximity to faults, land covers, rainfall classes, and proximity to streams was constructed in GIS and subsequently normalized using fuzzy membership functions. Finally, by combining all standardized layers using the fuzzy gamma operator, a final map of LSZ was produced. The results showed that a 0.9 fuzzy gamma operator has a high accuracy for the LSZ map in the study area. Besides, the accuracy of the LSZ map revealed a strong relationship (R2) between susceptibility classes, and landslide inventory was calculated using a scatter plot equal to 0.79. Hence, the method represented an appropriate accuracy in predicting the landslide susceptibility in the study area

Data on arsenic contamination in groundwater of Rafsanjan plain, Iran

This data article focuses on the arsenic in the groundwater of Rafsanjan plain in Kerman Province of Iran where the groundwater is being extensively used for drinking and irrigation of pistachio gardens. The measured arsenic concentrations range from 4 to 278 μg/L (with an average of 59 μg/L). About 85.3% of water samples have arsenic concentrations above 10 μg/L provided by the World Health Organization, WHO, guideline value. This data article provides also map showing the concentration of arsenic in groundwater of Rafsanjan area based on the situation of the sampling points in Rafsanjan region

Spatiotemporal subsidence over Pabdana coal mine Kerman Province, central Iran using time-series of Sentinel-1 remote sensing imagery

Environmental monitoring of mining regions using satellite imagery is crucial for sustainable exploitation and preventing geohazards. Movements due to the failure of the roof in underground coal mining, by migrating upwards and outwards from the seam being mined, could eventually appear as ground deformation. To investigate the matter further, the surface deformation that occurred over the Pabdana mining area was monitored in three time periods, between October 2, 2014, and July 27, 2019. Persistent scatterer interferometry (PSI) was used based on 150 ascending and descending Sentinel-1A images. The maximum mining subsidence rate during the studied periods was about 30 to 35 mm/yr. The PSI analysis shows that the subsidence rate varied both temporally and spatially during the three studied periods. The time series and the displacement rate for various cross-sections highlight a clear quantitative relationship between coal extraction progress and subsidence, which proceeded southward throughout the three study periods. So, considering coal mining subsidence as a geohazard, land developments and structures over the mining area may be safeguarded. The approach used in this investigation can be implemented in other similar coal mining zones

Discontinuous rock slope stability analysis by limit equilibrium approaches – a review

Slope stability is one of the most important topics of engineering geology with a background of more than 300 years. So far, various stability assessment techniques have been developed which include a range of simple evaluations, planar failure, limit state criteria, limit equilibrium analysis, numerical methods, hybrid and high-order approaches which are implemented in two-dimensional (2D) and three-dimensional (3D) space. In the meantime, limit equilibrium methods due to their simplicity, short analysis time, coupled with probabilistic and statistics functions to estimate the safety factor (F.S), probable slip surface, application on different failure mechanisms, and varied geological conditions has been received special attention from researchers. The presented paper provides a review to limit equilibrium methods used for discontinuous rock slope stability analyses with different failure mechanisms of natural and cut slopes. The article attempted to provide a systematic review for rock slope stability analysis outlook based on limit equilibrium approaches