Slope Type Research Articles

Penentuan Jenis Tanaman Berdasarkan Kemiringan Lahan Pertanian Menggunakan Adopsi Linier Programming Berbasis Pengolahan Citra

The slope is a measure of the slope of the land relative to the flat plane which is generally expressed in percent or degree. Agricultural land that has a slope of more than 15 ° can be more easily damaged. In this study, a value of 2.5 ° was used in determining the normal slope. The process of implementing a decision support system used linear programming adoption in determining the slope angle of the land, rotation of the slope of the land and determining whether or not the normalization of the input image was necessary or not. The purpose of this research is to determine the time needed to determine the type of plant based on rotation or the angle of setting determined by the user. The results of the study are the greater the height and width of an object the longer the time needed to determine the type of plant, land price or slope of the land. The results of the study were obtained in five tests. Tests 1 and 2 images with height and image width ranged from 150-480 obtained time for normalization of 15-30, testing 3.4.5 images with height and image widths ranging from 322 and 788 requiring 54- 108. Keywords: Slope, Adopting Linear Programming, Decision Support Systems

Limit-Equilibrium Analysis of Stability of Footwall Slope with Respect to Biplanar Failure

AbstractBiplanar failure is the most common instability type of footwall slopes, with a steeply dipping joint (typically the bedding plane) and a gently dipping joint (i.e., the daylighting toe joi...

VC++ Software Development and Stability Analysis of a Slope Based on the Slice-Free Method

Because the traditional slice method depends on an inexact assumption, stability analysis can be applied in slope engineering using another approach that involves the entire block without slicing. This approach is defined by the force-moment equilibrium system. The moment is converted into the integral of the force against the outline of the slope using the boundary integral. Because of the complexity of the irregular slope outline, a software program based on VC++ is developed for slope stability analysis. The software is programmed with a single document project, which embeds three complete modules for pretreatment, solution calculation and postprocessing. To visualize the parameters, graphics and output, a flexible software operation interface is created by enriching the class libraries and controls. The program is applicable to different types of slopes as well as complex algorithms. A sample analysis reveals that the safety coefficient is consistent with the analysis results of the most dangerous slip surface, which further verifies the accuracy and reliability of the software. Control points and single point search steps are set based on the previous custom slip surface (polyline). A series of safety coefficients are calculated over a certain area. Finally, the most dangerous slip surface of the slope is identified based on the control points corresponding to the minimal safety coefficients.

Пространственно-географический анализ склоноформирующих процессов Щербаковской излучины Волги

The article provides information about the Genesis and modern relief formation of Shcherbakov bend of the Volga. The role of the lithological-tectonic factor in the isolation and evolution of the external appearance of the bend is emphasized. The characteristic of the tiered relief of the considered territory and transforming its appearance of slope-forming processes: erosion and gravity is given. The role of each in the formation of different types of slopes of Shcherbakov bend is emphasized.

Evaluating failure mechanisms of dip slope using a multiscale investigation and discrete element modelling

This study proposed an in-depth multiscale analysis procedure to identify the dip slope area and assess dip slope stability and influencing area. The proposed analysis procedure comprised five stages: (1) identifying the potential area of a dip slope, (2) analyzing the possible failure types of the dip slope, (3) evaluating slope activity, (4) analyzing dip slope stability under the influence of possible triggering factors, and (5) assessment of the deformation and deposition area. To validate the proposed procedure, the Chaochouhu region of Taiwan was analyzed as a dip slope case. In stages (1) to (3), the scale of the utilized map and the precision of associated data were evaluated to identify the potential area of a dip slope, the possible failure types, and the activity of each slope unit. In stages (4) and (5), the processes of deformation and sliding in a high-activity slope unit were simulated using the discrete element method. The numerical model was first verified using in-situ monitoring data obtained from inclinometers. Subsequently, the model was used to predict the slope behavior under conditions of wetting deterioration of geomaterial. The multiscale analysis revealed comprehensive information regarding the dip slope. The application of the proposed approach would be useful to civil engineers for evaluating dip slope stability as well as to relevant authorities for planning hazard mitigation strategies.

New approaches to modelling of local seismic amplification susceptibility using direct characteristics of influencing criteria: case study of Bam City, Iran

Abstract. This paper proposes a new model in evaluating local seismic amplification susceptibility by considering direct characteristics of influencing criteria and it deals with uncertainty of modelling through production of fuzzy membership functions for each criterion. For this purpose, relevant criteria were identified by reviewing previous literature. These criteria include alluvial thickness, stiffness and strength of alluvial deposits, type of soil and particle size distribution of alluvial deposits, depth of groundwater, type of rock, topographic irregularities, slope, and type of bedrock. Two methods, analytic hierarchy process (AHP) and fuzzy logic (FL), were applied in order to define priority rank of each criterion and sub-criteria of each criterion through interview data of 10 experts. The criteria and sub-criteria were combined using the weighted linear combination method in GIS to develop a model for assessing local seismic amplification susceptibility in the study area of Bam City, Iran. The model's output demonstrated high to very high seismic amplification levels in central, eastern, northeastern, and northern parts of the study area. The validation results based on overall accuracy and kappa statistics showed 73.6 % accuracy, with 0.74 kappa indicating a good fit to the model's output. This model assists planners and decision makers in determining local seismic amplification susceptibility to be incorporated in designing new development plans of urban and rural areas and in making informed decisions regarding safety measures of existing buildings and infrastructures.

Reducing Nitrogen and Phosphorus Losses from Different Crop Types in the Water Source Area of the Danjiang River, China.

Nitrogen and phosphorus are essential for plant growth and are the primary limiting nutrient elements. The loss of nitrogen and phosphorus in agricultural systems can cause the eutrophication of natural water bodies. In this paper, a field simulated rainfall experiment was conducted in a typical small watershed of the Danjiang River to study the nutrient loss process of nitrogen and phosphorus in slope croplands subjected to different crops and tillage measures. The characteristics of the runoff process and nutrient migration of different slope treatments were studied, which were the bare-land (BL, as the control), peanut monoculture (PL), corn monoculture (CL), bare land (upper slope) mixed with peanut monoculture (lower slope) (BP), corn and peanut intercropping (TCP), corn and soybean intercropping (TCS), downslope ridge cultivation (BS) slope, and straw-mulched (SC), respectively. The results showed that the runoff of CL, SC, TCS, BS, BP, PL and TCP slope types were 93%, 75%, 51%, 39%, 28%, 12%, and 6% of the those of the bare land, respectively. The total nitrogen concentration in runoff on different slope types decreased in the order of BP > PL > BS > SC > TCP > BL > CL > TCS. The BL was characterized with the highest NRL-TN (the loss of total nitrogen per unit area), with the value of 1.188 kg/hm2, while those of the TCP is the smallest with the value of 0.073 kg/hm2. The total phosphorus concentration in runoff decreasd in the order of BS > BP > PL > BL > TCP > SC > CL > TCS. The PRL-TP (the loss of total phosphorus per unit area) of BL is the largest (0.016 kg/hm2), while those of TCP is the smallest (0.001 kg/hm2). These indicate that the loss of nitrogen is much higer than that of phosphorus. The loss of nitrogen in runoff is dominated by nitrate nitrogen, which accounts for 54.4%–78.9% of TN. Slope croplands in the water source area should adopt the tillage measures of TCP and PL.These measures can reduce 85% of the runoff of nitrogen and phosphorus compared to the bare land. The results may assist in agricultural non-point source pollution control and help promote improved management of the water environment in the Danjiang River’s water source area.

Effectiveness of Non-monitored Green Roofs for Stormwater Management

A green roof is an alternative roofing system of any building or house that provides a better environment for urban areas. It has the potential to mitigate urban water problems. This study aims to investigate the rainfall runoff performance of two non-monitored green roofs with two different slopes. The experiment uses two types of non-monitored green roofs, namely flat roofs and sloped roofs that were exposed to climatic conditions in Parit Raja. The physical characteristics of the roofs were observed and rainfall runoff data was collected. The results showed that when 4 L of water was manually poured onto the roofs, an average of 60.4% of water was retained on sloped roofs whereas 48.4% was retained on flat roofs. Based on the 5-minute interval data, the retention ranges between 55.6% and 71.2% for both roofs. In terms of daily rainfall for a week, the average percentage was 69.2% for sloped roofs and 70.6% for flat roofs. All three approaches show that the green roofs produced less water runoff compared to normal roofs with both slopes retained water efficiently. Therefore, rainfall runoff performance for two types of green roof slopes was investigated and the available storage for the green roofs was recorded. In conclusion, with little maintenance, non-monitored green roofs can be efficiently used as a water mitigation system for urban areas

Evaluation of Land Suitability of Horticultural Crops in Sembalun Sub-district, East Lombok Regency, Indonesia

This research aims to discover the data of land characteristic/quality, land suitability, limited factor, and improvement effort, directives of use and map of suitability for horticultural crops. The crops that are evaluated include red chili, onions, garlic, oranges, and apples. The selection of commodities is based on fluctuating production data, them are superior plant, and has a good market price. This research was conducted in November 2017 until January 2018 in Sembalun Lawang Village and Sembalun Bumbung Village, Sembalun Sub-district East Lombok Regency. Soil analysis was conducted in Soil Laboratory of Agriculture Faculty of Udayana Universit. It was analyzed using GIS modelling. Obtained six units homogeneous of land based on the result overlapped type of soil, land used and slopes, that is SBAISw, SBAIITg, SBAIVTg, SLHISw, SLHIITg, and SLHIVTg. The Land suitability assessment based on criteria requirements grew from Ritung et al., matchs with land characteristic/quality [1]. The result showed that the actual suitability class of land for horticultural crops was appropriate (S2) until they were not appropriate (N). Limited factors in the research area among others temperaturee (tc), rainfall (wa1), long dry months (wa), drainage (oa), textures (rc1), CEC (nr1), N-Total (na1), P2O5 (na2), slopes (eh1), and the dangers of erosion (eh2). Improvement of land suitability class can be done with improvement effort except temperaturee, long dry months and texture because they are permanent divider. Giving organic materials can improve soil physical and chemical properties. Slopes and the dangers of erosion can be improved by conservation tehcniques such as terracing. Class of potential land suitability was appropriate (S2) until they were marginal appropriate (S3). Land use of recommendations on SBAISw, SLHISw, and SBAIITg land are red chilli, garlic, and onion. SLHIITg, SBAIVTg, and SLHIVTg recommended for red chili, orange and apple crops based on agro-ecosystem, agroeconomic, and field observation.

Geological characteristics and enrichment laws of normal-pressure shale gas in the basin-margin transition zone of SE Chongqing

The southeastern Sichuan Basin and its basin-margin transition zone (hereinafter referred to as “the basin-margin transition zone of SE Chongqing”) is the focus of normal-pressure shale gas exploration in China. In order to summarize the geological characteristics and enrichment laws of shale gas in the basin-margin transition zone of SE Chongqing, we analyzed the geological characteristics of shale gas reservoirs in the Nanchuan–Wulong area of this transition zone from the aspects of sedimentary formation, tectonic reworking and production characteristics by using geophysical, drilling, logging and testing data, and then we compared it with the overpressure shale gas reservoirs in the Jiaoshiba Block. Finally, we explored the main factors controlling the enrichment & high yields of normal-pressure shale gas in this transition zone and their hydrocarbon accumulation patterns. And the following research results were obtained. (1) Different from the over-pressure shale gas reservoirs in Jiaoshiba Block, the normal-pressure shale gas reservoirs in this transition zone are characterized by lower organic porosities, more developed micro-fractures, higher ratios of adsorbed gas, greater differences of stresses in two directions, lower geothermal gradients, lower formation pressure coefficients, higher initial fluid production rates and higher fluid flowback rates. (2) The enrichment & high yields of normal-pressure shale gas in this area is mainly controlled by three factors, i.e., carbon-rich, silicate-rich and graptolite-rich shale, organic pores, and tectonic stress field, among which, the first factor controlled by deepwater continental shelf facies is the basis of shale gas enrichment, the second is the main controlling factor of shale gas enrichment, and the third is the key factor of high-yield shale gas. (3) The hydrocarbon accumulation patterns of normal-pressure shale gas reservoirs in the transition zone can be divided into four types, including the anticline type, the syncline type, the slope type and the reverse fault type. And the enrichment & high-yield characteristics of shale gas in different hydrocarbon accumulation patterns are also clarified. In conclusion, the research results enrich the geological theory of enrichment & high-yield laws of normal-pressure shale gas and provide a support for the exploration and development of normal-pressure shale gas in complex structures.

Predicting Sheet and Rill Erosion of Shihmen Reservoir Watershed in Taiwan Using Machine Learning

Shihmen Reservoir watershed is vital to the water supply in Northern Taiwan but the reservoir has been heavily impacted by sedimentation and soil erosion since 1964. The purpose of this study was to explore the capability of machine learning algorithms, such as decision tree and random forest, to predict soil erosion (sheet and rill erosion) depths in the Shihmen reservoir watershed. The accuracy of the models was evaluated using the RMSE (Root Mean Squared Error), MAE (Mean Absolute Error), and R2. Moreover, the models were verified against the multiple regression analysis, which is commonly used in statistical analysis. The predictors of these models were 14 environmental factors which influence soil erosion, whereas the target was 550 erosion pins installed at 55 locations (on 55 slopes) and monitored over a period of approximately three years. The data sets for the models were separated into 70% for the training data and 30% for the testing data, using the simple random sampling and stratified random sampling methods. The results show that the random forest algorithm performed the best of the three methods. Moreover, the stratified random sampling method had better results among the two sampling methods, as anticipated. The average error (RMSE relative to 1:1 line) of the stratified random sampling method of the random forest algorithm is 0.93 mm/yr in the training data and 1.75 mm/yr in the testing data, respectively. Finally, the random forest algorithm predicted that type of slope, slope direction, and sub-watershed are the three most important factors of the 14 environmental factors collected and used in this study for splits in the trees and thus they are the three most important factors affecting the depth of sheet and rill erosion in the Shihmen Reservoir watershed. The results of this study can be employed by decision-makers to improve soil conservation planning and watershed remediation.

Integrated Wind Farm Power Curve and Power Curve Distribution Function Considering the Wake Effect and Terrain Gradient

This work presents a computational method for the simulation of wind speeds and for the calculation of the statistical distributions of wind farm (WF) power curves, where the wake effects and terrain features are taken into consideration. A three-parameter (3-P) logistic function is used to represent the wind turbine (WT) power curve. Wake effects are simulated by means of the Jensen’s wake model. Wind shear effect is used to simulate the influence of the terrain on the WTs located at different altitudes. An analytical method is employed for deriving the probability density function (PDF) of the WF power output, based on the Weibull distribution for describing the cumulative wind speed behavior. The WF power curves for four types of terrain slopes are analyzed. Finally, simulations applying the Monte Carlo method on different sample sizes are provided to validate the proposed model. The simulation results indicate that this approximated formulation is a possible substitute for WF output power estimation, especially for the scenario where WTs are built on a terrain with gradient.

Experimental investigation on the failure mechanism of a rock landslide controlled by a steep-gentle discontinuity pair

A type of rock landslide is very common in practical engineering, whose stability is mainly controlled by the rock bridge between the steep tensile crack at the crest and the low-inclination weak discontinuities at the toe (namely, ligament is the term for the locking section in the slope). To obtain a deeper understanding into the failure process of this kind of landslide, twenty-four physical slope models containing a steep-gentle discontinuity pair (a steep crack in the upper part and a low-inclination discontinuity in the lower part) were tested by applying vertical loads at the crests. The results indicate that the inclination angle of the ligament (θ) has great influence on the failure and stability of this type of rock slope. With the change of θ, three failure patterns (five subtypes) concerning the tested slopes can be observed, i.e., tensile failure of the ligament (Type 1), tension-shear failure of the ligament (Type 2) and two-stage failure of the main body (Type 3). The failure process of each failure mode presents five stages in terms of crack development, vertical load, horizontal/vertical displacements and strains in the ligaments. The specific range of the ligament angle between different failure patterns is summarized. The discussion on the failure resistances and ductility of different failure patterns, and the guiding significances of the experimental findings to the stability evaluation and the reinforcement were conducted.

Model test study on the hydrological mechanisms and early warning thresholds for loess fill slope failure induced by rainfall

Under rainfall conditions, the characteristics of hydraulic changes related to the failure evolution of fill slopes are critical to the early warning of slope failure. In this study, a series of model tests are carried out on loess fill slopes with different slope types. The matric suction, volumetric moisture content, pore water pressure and deformation of the slope are monitored in real time during the rainfall process. Meanwhile the development of cracks and the failure modes of the slope are analyzed, and then the early warning strategy of fill slope failure induced by rainfall is studied. The results show that loess landslides induced by rainfall exhibit a hysteresis. However, the volumetric water content and the matrix suction respond earlier than the pore water pressure. The slope failure is produced when the volumetric water content and the matrix suction are respectively at their maximum and minimum values. The evolution mechanism of cracks on the slope starts when tensile cracks are first generated near the leading edge surface and then extend backwards. In the next stage, shear fracture is produced near the flanking of the slope and finally, the trailing edge produces a transfixion tensile crack from the top to toe of the fill slope, which not only provides the advantage of an infiltration channel to control the hydrological process, but also evolves into the trailing edge boundary of each failure of fill slope. With the increase of rainfall duration, the filling slope presents different failure characteristics, revealing the hydraulic behavior of a partially saturated slope. In addition, combined with the infinite slope stability analysis in Mohr–Coulomb soil, the matrix suction and volumetric water content thresholds of the fill slopes with different slope angle are determined. The early warning threshold model for rainfall induced slope instability is proposed and a new framework of early warning is provided.

Effects of igneous bodies on modification of modern slope morphology: Insights from the continental slope offshore Dongsha Islands, South China Sea

A statistical analysis for the morphological parameters extracted from numerous seismic profiles, and a highresolution seismic study of the southeastern slope of the Dongsha Islands (South China Sea) with water depth between approximately 500 and 3 100 m, has revealed the variation of morphological features due to the intrusion of igneous bodies and associated sedimentary processes. Three types of the continental slope are distinguished: (1) a rough and steep slope with multiple igneous bodies (Type 1), (2) a relatively smooth and gentle slope with the single igneous body (Type 2), and (3) a smooth and gentle slope without igneous bodies (Type 3). These igneous bodies, formed in the post-seafloor spreading of the South China Sea, are often characterized by high positive seismic amplitudes, and chaotic reflections with complex shapes. The igneous bodies in Type 1 separated the slope into two or more upper sub-sags and a lower main-sag, in which the sub-sags and main-sag could be filled with sediments transported by alongslope bottom currents at the same time. Whereas, the igneous body in Type 2 just separated the slope into an upper sub-sag and a lower main-sag, in which the sediments could be transported into the lower main-sag only after the upper sub-sag has been filled up. Type 3 represents a normal slope with common clinoform progradation. The modern slope morphologies in the study area are the results of adjustments of the continental slope due to the intrusion of igneous bodies and associated sedimentary processes. The distinctions among three types of modern slope morphologies indicate different depositional conditions and adjustments of slope morphologies.

Numerical Calculation of Instability of Tunnel Surrounding Rock Based on Elastic Hole Theory

The instability and unloading of surrounding rock structure in tunnel under TBM construction condition can easily induce large-scale rock caving in heading face, which seriously restricts safe and efficient tunneling. Aiming at the instability problem of surrounding rock structure of tunnel constructed by TBM, four types of slope induced by excavation disturbance are summarized systematically based on elastic hole theory, and the instability mechanism of roof structure and surrounding rock of tunnel is analyzed; the instability mechanism and catastrophic characteristics of surrounding rock structure of tunnel are analyzed by FLAC3D finite element numerical calculation software, and the roof transportation of tunnel after supporting is carried out. The amount of movement is greatly reduced and the overall failure degree of overlying strata is slowed down. The results show that the roof is prone to structural instability under the influence of tunneling disturbance. Tunnel support can effectively hinder the movement of overlying rock roof and floor, alleviate the probability of rock mass catastrophe, effectively control the dynamic disasters, and achieve safe tunneling.

Multi-criteria-based sub-basin prioritization and its risk assessment of erosion susceptibility in Kansai\u2013Kumari catchment area, India

Environmental processes are interrupted by the water action like soil erosion, mass movement as well as siltation on the dam in the undulating catchment area. Soil erosion is one of them and degraded the basin potentiality. This paper demonstrates that erosion susceptibility status in the 13 sub-basins of Kansai–Kumari catchment area has been determined depending upon its morphometric, lithology, geomorphic, land use/land cover (LULC), slope and soil characteristics used by integrated micro-watershed prioritization rank which is based on susceptible capacity under geographical information system platform. Risk assessment of soil erosion was measured by hypsometric characteristic (Hi) and denudation rate (tu) to assess the geological stage of landform and risk status for conservative practices. The result shows that SB13, 2 have a high risk (tu > 90 t/km2/year) due to the presence of low priority rank of morphometric, geomorphic, slope, soil and high priority rank of lithological set-up and LULC but reached under the late mature geological stage (Hi > 0.35). SB3, 4, 10 have a low risk (tu < 83 t/km2/year) due to the presence of high priority rank of morphometric, geology, geomorphic, slope and soil types under the mature stage of geological setting (Hi > 0.5). But SB7, 8, 9 have the medium risk (tu < 85 t/km2/year) due to the presence of erosion-prone LULC patterns like cropland and laterite cover but having low final priority rank and old geological stage (Hi < 0.35). Therefore, erosion susceptibility does not depend on morphometric aspects but also depends on other determinant themes at the sub-basin level.

Sensitivity analysis of toppling deformation for interbedded anti-inclined rock slopes based on the Grey relation method

Toppling deformations generally develop in interbedded anti-inclined rock slopes in the upper reaches of the Yalong River in southwest China. With the characteristics of large scales, strong deformation degrees and complex deformation modes, toppling bodies may eventually lead to instability failure in the form of landslides, which seriously threaten the construction and operation of hydropower stations in the basin. Taking three typical examples of toppling failures for interbedded anti-inclined rock slopes in the basin, the sensitivity analysis of 19 impact factors affecting the toppling deformation of this type of slope is obtained via the Grey correlation method and UDEC. The results show that the geometric parameters represented by slope angles are the most sensitive to toppling deformation, the mechanical parameters of joints are more sensitive to toppling deformation than the physical and mechanical parameters of intact rocks, and the sensitivities of the parameters of sandstone and slate gradually converge in the deformation process.

Sequence stratigraphy and lithofacies paleogeography of the Middle–Upper Cambrian Xixiangchi Group in the Sichuan Basin and its adjacent area, SW China

Abstract Based on isotopic, lithologic and electrical data and logging cycle analysis technique, stratigraphic sequences in the Middle–Upper Cambrian Xixiangchi Group in the Sichuan Basin and its adjacent area are divided, and its sedimentary characteristics and evolution are analyzed. The Xixiangchi Group can be divided into 5 third-order sequences (Sq1–Sq5), of which sequences I to III (Sq1–Sq3) are relatively complete, sequences IV and V are denuded in the Late Cambrian because of the Dian-Chuan paleo-uplifts. Third-order sequences of the Xixiangchi Group in this area have the characteristics of thin in the west and thick in the east, showing that the Caledonian paleo-uplift is a synsedimentary paleo-uplift and the paleogeomorphology in the platform is a gentle slope. Sequence I develops high stand systems tract and transgressive systems tract. The other third-order sequences are dominated by highstand systems tracts, and the transgressive systems tracts last shortly in time and are limited in area. The basic features of evaporative–restricted platform of gentle slope type developed continuously in the sedimentary period of the Xixiangchi Group, its sedimentary environment of “high in west and low in east” and the change of micro paleogeomorphology in the platform control the continuous development of sedimentary facies. Open platform is developed only in sequence I and sequence II, and the inner beach of the platform and the edge beach of the platform are mostly developed in sequence II and sequence III. It indicates that there are two platform margin zones in the study area, a relatively stable, large-scale platform marginal zone in NE Guizhou–Western Hunan and Hubei, and a moving and small-scale platform marginal zone in North Chongqing–Western Hubei.

Экодиагностические показатели характерных типов почв северо-восточного склона Большого Кавказа на примере Шабранского района Азербайджана

The article provides a brief description of the physical–geographical location of the study area. Geomorphological, geological conditions of formation, climatic and hydrological conditions, morphogenetic description of the soil profile of characteristic soil types and analysis of diagnostic indicators of the current state of characteristic types of the northeastern slope of the Greater Caucasus are given according to the International WRB system.