Slope Type Research Articles

Study of rock slope stability for formation outcrops in limb north eastern poor anticline North Iraq

This Study aims at rock Slopes Stability for formation in limb northـeastern poor anticline (Fatha, Injana and Mukdadyah). In (5) Stations, representing all types of failures (taken place and possible). General Survey for rock Slopes included Classification and engineering description according to [1][2]. The slopes in the area are Classified based on the direction of the Strike Slopes and Strike of beds into Parallel and Oblique Lateral Slopes according to [3] Classification and the Slope Types are Concordant Slope and discordant Slope.
 The main modes of Failures involved rock Fall and Toppling. The Plane Sliding possible with existence conditions must occurrence of Failure. In addition to rolling and Slumping Which Some times Follows the above mentioned Modes of Failures. The main reasons for Failures occurring are differential Weathering Which Cause to over hanging Slopes by under Cutting in addition to the discontinuities in rocks Masses.

Landslide Susceptibility Assessment in the Japanese Archipelago Based on a Landslide Distribution Map

Though danger prediction and countermeasures for landslides are important, it is fundamentally difficult to take preventive measures in all areas susceptible to dangerous landslides. Therefore, it is necessary to perform landslide susceptibility mapping, extract slopes with high landslide hazard/risk, and prioritize locations for conducting investigations and countermeasures. In this study, landslide susceptibility mapping along the whole slope of the Japanese archipelago was performed using the analytical hierarchy process (AHP) method, and geographic information system analysis was conducted to extract the slope that had the same level of hazard/risk as areas where landslides occurred in the past, based on the ancient landslide topography in the Japanese archipelago. The evaluation factors used were elevation, slope angle, slope type, flow accumulation, geology, and vegetation. The landslide susceptibility of the slope was evaluated using the score accumulation from the AHP method for these evaluation factors. Based on the landslide susceptibility level (I to V), a landslide susceptibility map was prepared, and landslide susceptibility assessment in the Japanese archipelago was identified. The obtained landslide susceptibility map showed good correspondence with the landslide distribution, and correlated well with past landslide occurrences. This suggests that our method can be applied to the extraction of unstable slopes, and is effective for prioritizing and implementing preventative measures.

Numerical analysis of slopes treated by nano-materials

Abstract Improvements in mechanical characteristics of soils treated by nano-materials (NMs) have been proved in the last three decades. The improvements are mainly attributed to changes in the soil fabric where a noticeable rise in shear strength has been obtained. This work, therefore, addressed a numerical study on the influence of the soil fabric changes due to the NMs enhancement on a slope stability problem using an upper bound discretization scheme. A parametric study was carried out at seven different inclination angles from 15 to 45° and with a variety of combinations of angle of shearing resistance (ϕ) and cohesion (c) values. This was carried out for two different types of slopes on purely frictional materials and c–ϕ materials. A noticeable increase in stability was obtained, based on a set of re-generated design charts, due to NMs enhancement (attributed to soil fabric changes). The re-generated design charts did not require iterative procedures and extended both x and y boundaries when compared with other available charts in the literature. Examination of the influence of the NM on the failure modes, to provide an insight into different failure mechanisms due to the soil fabric changes, was also considered.

Geoecological risks in the valleys of small rivers of the forest-steppe zone of the Russian plain (on the example of the Chuvash Republic)

The Chuvash Republic belongs to the territories with a high frequency of occurrence of emergency situations of moderate severity. This is due to the intensive economic development of the region. The probability and intensity of the manifestation of georisks is different for individual landscapes, therefore it needs a detailed study. The study includes the study of the probability of the development of slope, climatic, hydrological risks, and the risk of wildfires on the territory of the Chuvash Republic. The analysis showed that the slope type of geoecological risk is confined to the river valleys of the region and has maximum values in the north of the Chuvash Republic. A high risk of flooding and flooding exists in the valleys of major rivers of the region (Volga, Sura) and their tributaries of the first order. On other watercourses, the hydrological risk is not significant. Climate and weather risks are associated with hurricane winds and dry winds. The southeastern part of the region suffers the most from them. The risk of fires depends on the composition and age of the stand. The maximum risk values are typical for the Prisursky forest area (southern and southwestern parts of the region). Based on the data obtained, the classification of the districts of the Chuvash Republic by the size of the georisks was carried out. Four groups of districts were identified according to the probability of natural emergencies and the main factors of their occurrence were described.

Hydrocarbon accumulation conditions and exploration targets of the Sinian Dengying Formation in the Southeastern Sichuan Basin

No breakthrough has been made in petroleum exploration of the Sinian Dengying Formation in the southeastern Sichuan Basin as the major factors controlling the hydrocarbon accumulation of the Dengying Formation have not been well established, including the development period and distribution of the platform margin, the effectiveness of the source-reservoir combination and the reliability of the Cambrian pre-salt structural trap. Based on the interpretation of seismic data and hydrocarbon-source correlation, the distribution of the platform margin of the Sinian Dengying Formation in the southeastern Sichuan Basin was mapped. Moreover, the gas source rocks of the Dengying Formation were clarified according to geochemical characteristics of fluid inclusions, and the pre-salt structures were further confirmed by seismic forward modeling and experiments of prestack depth migration. Results showed that the sedimentary facies of the 4th member of Dengying Formation in the southeastern Sichuan Basin was platform margin of gentle slope type. The platform margin reservoir of the Dengying Formation and the Lower Cambrian source rocks constitute a favorable source - reservoir combination. The carbon isotope characteristics of gas in fluid inclusions indicate that some of the oil/gas in the Dengying Formation were contributed by the Doushantuo Formation source rocks. As the difference in seismic velocities between carbonate rocks and gypsum/salt beds may cause a reduction in the amplitude of pre-salt structures, the low-amplitude structures identified on current seismic profiles are underestimated instead of overestimated. Accordingly, the Sinian structural traps are confirmed to develop in the deep pre-salt sequences in the low-steep anticline belt, southeastern Sichuan Basin. On the basis of the above new understanding, we propose two types of hydrocarbon migration modes for the Sinian Dengying Formation in southeastern Sichuan Basin, including lateral migration of hydrocarbons generated from the Cambrian Qiongzusi Formation and vertical migration of hydrocarbons derived from the Sinian Doushantuo Formation. Lithologic traps at the platform margin and pre-salt structural traps within the platform are favorable targets for natural gas exploration.

Evaluating earthquake-induced widespread slope failure hazards using an AHP-GIS combination

Landslides and slope failures are often caused by earthquakes. This study proposes a method to map earthquake-induced slope failure hazards that uses the analytic hierarchy process (AHP) and a geographic information system (GIS) for four districts where many slope failures were induced by earthquakes (the 2018 Hokkaido Eastern Iburi, 2016 Kumamoto, 2008 Iwate-Miyagi Nairiku, and 2004 Mid Niigata Prefecture earthquakes). The assessment system, which was based on the National Research Institute for Earth Science and Disaster Resilience landslide distribution maps, was analyzed using the methods of previously published. We considered the relationships between the earthquake-induced slope failure distributions and landslide hazard factors (elevation, slope angle, slope type, catchment degree, geology, and vegetation). These relationships were utilized for pairwise comparisons of the factors in the AHP analysis. The slope angle, slope type, and catchment degree exerted the highest effects on the slope failure distribution in the four districts. The four earthquake-induced slope failure distributions were highly consistent with the slope failure hazard rank. These results provide a practical method for evaluating earthquake-induced slope-failure hazards.

Chart-Based Granular Slope Stability Assessment Using the Modified Mohr–Coulomb Criterion

There are usually two types of slopes in nature: soil and rock. However, the granular slope has gradually come into view and has caused concern. In this paper, a modified Mohr–Coulomb (MC) criterion has been proposed to estimate the strength parameters of medium materials using a new parameter (tau_{0}) instead of the traditional MC parameter (c). Meanwhile, there is a new stability chart of a granular slope whose core is the dimensionless stability number Ns and dimensionless coefficient DR based on a modified MC criterion to estimate the safety factor of a granular slope preliminarily when the geometric and strength parameters of the slope are determined. A practical case is introduced to test the results, showing that the stability chart proposed in this paper is applicable to granular slopes. The research content and the proposed new viewpoints are intended to offer preliminary judgments on the stability analysis of granular slopes and provide guidance for the stability analysis and construction design of granular slope engineering.

Insights from size fractions to interpret the erosion-driven variations in soil organic carbon on black soil sloping farmland, Northeast China

Declines of soil organic carbon (SOC) and degradation of soil function are caused by long-term soil erosion and cultivation. Although the variations of bulk SOC have been extensively studied, the driving mechanisms of variations in SOC fractions, i.e., carbon in coarse particulate, fine particulate, and mineral-associated organic matter (CPOM-C, FPOM-C, and MAOM-C), and their relationship with soil erosion remain unclear on sloping farmland. In this study, two areas of farmland with different slope types (convex vs. straight) and reclamation periods (50 years vs. ≥100 years) in the black soil region of Northeastern China were chosen to explore the roles of soil erosion on the variations of SOC and their size fractions based on the 137Cs tracer technique. The results showed that the average net erosion rate of the straight slope was 2810.09 t km-2a-1 and the convex slope was 3801.71 t km-2a-1 with higher spatial variability. When compared with uncultivated land, SOC contents of convex and straight slopes have decreased by 13.58% and 35.18%, with a reduced rate of 0.089 g kg-1 a-1 and 0.116 g kg-1 a-1, respectively. Although the CPOM-C fraction showed the most significant relative decreases (over 73.24%), the absolute declines of MAOM-C were more significant, especially in the straight slope with a more extended cultivation period. The contributions of erosion to the SOC decreases on convex and straight slopes were 69.54% and 13.09%, respectively. Erosion exerted a significant influence on finer particles such as FPOM-C and MAOM-C. With increasing cumulative erosion, the absolute magnitude of each SOC fraction in soils decreased. But the proportion of MAOM-C increased, while FPOM-C and CPOM-C decreased. Overall, our findings demonstrated that soil erosion not only induced the loss of SOC fractions but also transformed the proportional distribution of their fractions, and then affected the functions of SOC. Moreover, the effects of tillage (i.e., an increase in microbial activity) on straight slopes are not negligible in farmland that has experienced long-term cultivation but relatively little erosion. Apart from erosion reduction in areas of severe erosion, appropriate fertilization for farmland with a long history of cultivation should also be adapted to achieve sustainable development of black soil resources.

Some considerations on the role of joint spacing in rock slope stability analyses using a 3D discrete element approach

Stability assessment of potential wedge failures in rock slopes is usually carried out based on stereographic projection techniques and limit equilibrium analyses. Nevertheless, this methodology presents several limitations (i.e., lack of information on joint mechanical properties, oversimplification of the structure, etc.) that could lead to poorly accurate conclusions. In line with this idea, the main objective of this work is to evaluate the effect of joint spacing in the estimation of the factor of safety of rock slopes affected by potential wedge failures. For this purpose, a 3D numerical distinct element code (3DEC) was selected to carry out a substantial number of simulations in which the factor of safety of two types of slopes, affected by different discontinuity sets, was studied by using the shear strength reduction (SSR) method. Different values of joint spacing, cohesion, and friction angles were considered, combined with two angles of the slope face under study. A discrete fracture network (DFN) model was also implemented, with the aim of benchmarking results with those obtained from the original models. The joint spacing has been found to relevantly affect the values of the factor of safety of the slope, which showed variations of up to 40% in comparison with those obtained from limit equilibrium methods. This work provides an insight to a more realistic interpretation of rock slope analyses against wedge failures, particularly to better estimations of the factor of safety.

The effect of geometric dimensions on the lateral bearing capacity of the masonry arches

The roofs of historic structures and old buildings are frequently covered using 5&7 brick arches. Since the design of these arches is usually done against gravity loads, they will probably be vulnerable to lateral loads. The estimation of the lateral bearing capacity of 5&7 brick arches is the main goal of this study, along with investigating the effect of geometric dimension parameters on the lateral bearing capacity of these arches. The models of the examined arches are in accordance with 5&7 arches of the low slope and steep slope types. The spans studied in this research are equal to 2.5, 4.5, 6.5, and 9.5 m, and the results have been tested for a case study, the main porch of Gonabad Grand Mosque in Iran. The specifications of the building materials used in this research were determined using laboratory studies, and all analyses were performed by ANSYS software. Evaluating the ratio of lateral load-carrying capacity to the weight of the structure for different arches showed that the optimal ratio of the thickness of the pier to the spans for low slope and steep slope 5&7 arches was about 0.24.

Morphological variation of coronoid process, sigmoid notch, and condylar process among patients of tertiary care centre of Nepal

Background: Mandibular ramus undergoes remodelling with time. The remodeling is also influenced by factors such as ageing, dental status, gender, stress, trauma, force exerted during occlusion, and joint diseases. Studies have reported variations in morphology of coronoid process, condylar process, and sigmoid notch of the mandible. Objectives: To assess the morphological variations of processes of mandible and the sigmoid notch in a tertiary care centre of Nepal. Methods: A retrospective study was conducted at Chitwan Medical College. This study included 310 orthopantomograms (OPGs) retrieved from the archives of the hospital data from 2022 May-June. All OPGs were taken with same radiographic equipment. Data taken in predesigned proforma were entered and analysed in SPSS v.16. Descriptive statistics was used to explain the results in tabulated form. Results: Among 310 OPGs assessed, 188 (60.6%) were female and rest male. Angled mandibular condyle was prevalent on both right 123 (39.7%) and left side 134 (43.2%). More than 50% of sigmoid notch was of sloping shape on both right and left side. Triangular type of coronoid process was present 185 (59.7%) on right side and 183 (59.0%) on left side. Among the coronoid process types, triangular was found more in male and females on both right and left sides. Conclusion: This study concluded that the angled type of condylar process, sloping type of sigmoid notch, and triangular type of coronoid process were more prevalent on both right and left side. All three parameters were also observed to be prevalent in females suggesting gender variation.

Responses of Infiltration Potential and Soil-Erosion Processes to Rainfall Patterns in Two Types of Slopes over the Eastern Region of the Tibetan Plateau

Responses of Infiltration Potential and Soil-Erosion Processes to Rainfall Patterns in Two Types of Slopes over the Eastern Region of the Tibetan Plateau

Influence of water erosion on the structure and content of labile humic substances in the structural-aggregate fractions of leached chernozems of the Central Chernozem region

The structural-aggregate composition of leached chernozems (Voronic Chernozems Pachic according to WRB-2014), the distribution of organic compounds Corg and labile humic substances (LHS) in the structural-aggregate fractions of carbon in the conditions of a slope type of terrain during the development of erosion were studied. The work was carried out in the northern part of the Voronezh region on the catena, which included a section of the watershed, smoothly turning into a southwestern slope about 1500 m long and 5˚ steep. The soils of the following sections of the catena were studied: 1) the watershed part; 2) the upper part of the slope; 3) the middle part of the slope. It was shown that degradation of the structural-aggregate state occurs in eroded chernozems, accompanied by a deterioration in microstructurality, a decrease in the number of mesoaggregates and a structural coefficient, as well as a loss of a water-resistant structure. According to the results, LHS play a very important role in maintaining the water-stable structure of chernozems. The most significant contribution to the content of Corg contribute mesoaggregates 5-1 mm in size, which are actively lost during the development of erosion.

Blood glucose kinetics during concentric and eccentric muscle contractions

Studies comparing the two classes of stimuli (concentric and eccentric) have shown differences in the improvement of cardiovascular, metabolic, and muscle strength gain. This is an experimental, quantitative, and prospective study that aimed to verify the effect of eccentric exercise on glycolytic consumption and kinetics. The blood glucose kinetics of 17 male subjects was evaluated during a treadmill exercise with a 10% declined floor and velocity that required a 60% metabolic activity of VO2max, for 30 minutes. Seventy-two hours later, the same subjects exercised on the treadmill with a 10% inclined floor and 60% VO2max, for 30 minutes. To quantify glucose, blood samples were collected before the exercise, every three minutes along the 30 minutes of physical activity, and five and 10 minutes after finishing the exercise. For the downward slope, there was a homogeneous group behavior for blood glucose dynamics during the exercise, which was characterized by a monotonic decrease of glucose levels until reaching a minimum value at experimental times between 20 and 30 min, followed by a progressive recovery toward initial values. For the acclivity condition, blood glucose dynamics did not follow such a homogeneous behavior. A set of different types of dynamics could be identified. Experimental data showed that the type of dynamics could be predicted, to some extent, by the basal blood glucose level of subjects. The type of floor slope (upward or downward) directly affected glycolytic consumption and kinetics for the individuals analyzed.

A New Multi-Objective Comprehensive Optimization Model for Homogeneous Slope Reinforced by Anti-Slide Piles: Insights from Numerical Simulation

Abstract Landslides have posed a huge threat to the ecological environment and human society all over the world. As the most conventional reinforcement method, anti-slide piles are widely used in the reinforcement of slopes. Currently, more and more attention has been paid to the low-cost and high-efficiency optimal design of anti-slide piles. However, limitations in the method of the optimization design for slopes reinforced with piles still exist. In this paper, a new multi-objective comprehensive optimization method was proposed for the optimization of the slope reinforced with anti-slide piles. The factor of safety, internal force, and deflection of piles were selected as the optimization indexes, and the optimization index weight was determined by integrating the subjective and objective weights. The influence of pile locations, pile lengths, and pile spacings on the reinforcement effect of a homogeneous slope was analyzed via the numerical simulation. Through the simulation case analysis, the proposed model had achieved good effects on the optimization design of anti-slide piles, which could effectively reduce the engineering costs. The optimization results showed that the best reinforcement effect for the homogeneous slope could be obtained when the anti-slide piles with the critical pile length and small pile spacing were located in the middle of the slope. This provides a new solution for the optimization design of other types of complex slopes and has broad application prospects.

Study on the threshold value of disaster-causing factors of engineering slope cutting in red-layer areas

Slope cutting is becoming more common in engineering construction to obtain a large floor area. Slope cutting disrupts a slope’s inherent stability, causing instability and sliding. To solve the problem of geological disasters caused by artificial slope cutting, Cangxi County is used as an example to analyze the cutting slope and the height of different slope structures in the county, to study the disaster mode and disaster factors caused by slope cutting, and to analyze the influence of slope cutting height and slope cutting gradient on the disaster process. This study demonstrates that the stability of cutting on different types of slopes is weakened to different degrees, with mixed rocky-soil slopes having the strongest resistance to weakening, thick-soil slopes the second strongest, and thin-soil slopes the weakest. Slope cutting is the main factor of disaster, and rainwater infiltration promotes landslide formation. Numerical simulation is employed to determine the proximities of the slope cutting height and slope cutting gradient, and 75% of the critical value is taken as the proposed threshold value of slope cutting. The recommended cut slope threshold value corresponds to the real stable cut slope gradient on site, and the research findings can be used to guide engineering cut slope decisions in Cangxi County and other red-layer areas.

The formation of small macro‐aggregates induces soil organic carbon stocks in the restoration process used on cut slopes in alpine regions of China

AbstractRoad construction in mountainous areas of China has formed bare slopes on a large scale, which has aggravated soil erosion and carbon loss, and the restoration processes have changed soil structure and fertility. However, there are few reports regarding the differences of soil aggregate dynamics and SOC sequestration under different restoration process for cut slopes. In this study, three types of cut slopes [cut slope restored naturally (CSN); cut slope restored with three‐dimensional mesh (CST); cut slope restored with galvanized wire mesh (CSG)] and natural slope (NS) in alpine regions were selected as the research objects. SOC stocks and their key driving factors were then analyzed. The results showed that CSG was more beneficial to the formation of macro‐aggregates than CSN and CST. There were significant differences in wet‐sieved aggregate stability under different restoration process, where the sort by strength of stability was NS > CSG > CST > CSN. Aggregate size was a more important factor for SOC stocks than restoration process. The increase of SOC stocks was mainly due to that within small macro‐aggregates. RandomForest analysis revealed that the mass proportion of micro‐aggregates was the most important factor affected SOC stocks, while SOC stocks within large macro‐aggregates and small macro‐aggregates and porosity significantly affected SOC stocks. Partial least squares path modelling analysis found the particle size and stability of aggregates had negative total effects on SOC stocks, and SOC content had positive total effect on that. Overall, for the ecological restoration of cut slope in alpine regions, CSG was most beneficial to increase soil aggregate stability and SOC stocks.

Physico-mechanical properties of the sandstones and effect of salt crystallization on them: A comparative study between stable and unstable slopes (a case study of the Khorramabad-Zal highway in Iran)

The Khorramabad-Zal highway is a road constructed in Lorestan province (southwest of Iran). With a length of 104 km, it connects Khorramabad and Andimeshk cities. Performing many excavations in sandstone outcrops along this highway has created stable and unstable slopes. The release of Na+ and SO42- ions due to weathering and dissolution of the marl and gypsum rocks has formed Na2SO4 salt in this area. Permeating this salt into the sandstones has led to the salt crystallization process in them. The present study investigates sandstones’ physico-mechanical properties in the stable and unstable slopes before and after salt crystallization test up to 15 cycles. To this end, 14 sandstone samples belonging to stable and unstable slopes were collected. Next, their physico-mechanical properties are characterized by determining their porosity (n), point load index (PLI), Schmidt hammer hardness (SHH), and slake durability index (SDI) before and after salt crystallization test in Na2SO4 solution (i.e., untreated and treated samples, respectively). The results indicate that samples of unstable slopes in untreated conditions generally have a higher n, and lower PLI, SHH, and SDI than those from the stable slopes. With increasing the salt crystallization test cycles, the samples’ n increased, while their PLI, SHH, and SDI decreased with different levels depending on the slope types. Overall, the deterioration effects of salt crystallization were more significant on the samples’ physico-mechanical properties belonging to unstable slopes, especially those subjected to salt crystallization under field conditions. This result was confirmed by the rate of loss (RL) of the samples’ physico-mechanical properties, and microscopic and macroscopic observations after the salt crystallization test. The deterioration in the physico-mechanical properties of sandstone samples caused by salt crystallization in field conditions increased slope instability near marl and gypsum rock outcrops. Finally, regression analyses showed that the SDI has good correlations with n, PLI, and SHH with determination coefficients (R2) of 0.919, 0.882, and 0.837, respectively. These correlations are accurate enough for use in the preliminary assessment of samples SDI from their n, PLI, and SHH. Finally, these correlations obviate the need to perform SDI as a laborious and time-consuming test.

Application of Geo Textiles in Erosion Control – A Review Paper

Geo textiles are a possible great alternative before vegetation establishes itself, and provides immediate control on soil erosion on different types of slopes. In this study, different geo textiles have been used for better erosion control over different soils. Different structurally modified geomeshes are tested for runoff erosion control, culmination discharge over different types of soils at different slope angles and at different rainfall intensities. Though these geo textile products are in use since a long time, the selection of product is mostly based on the manufacturer’s recommendations. Hence, there is a great necessity to understand the mechanics involved and to develop a comprehensive design methodology. In line with this, in the present study a review was done about the research takes place so far across the world.

Experimental study of effect of glass cover tilt angle of solar still in winter season of India’s composite climate

• Solar still’s performance in the winter season with nocturnal productivity. • Model-2 (TA 30°) above latitude angle performed good with 1660 ml/m2 yield, 17.25 % efficiency, and 1.1 % exergy efficiency . • Effect of covering condenser surface by insulating material in nocturnal yield. • Low tilt angle causes back drop of condensate into the basin. • Effect of wind velocity on outer surface temperature of condenser in daylight. The present work consists of an experimental investigation to find the effect of the tilt angle of the condenser surface of solar still (SS) on distilled water productivity and efficiency in the winter season in the metrological condition of Varanasi (25.2623°N, 82.9894°E), India. In this experiment, three models were fabricated with different tilt angles having the same basin areas. The first two models were single basin single slope (SBSS) type SS having tilt angles of 25° and 30° in southward facing. The third model was a single basin double slope (SBDS) type SS having a tilt angle of 15° facing toward the east–west direction. Generally, the latitude angle is used as a tilt angle however the present study revealed that the tilt angle varies according to season (sun-earth positioning) and affects productivity. The findings show the temperature difference between basin water and condenser glass cover is limited which is the driving force of the desalination process. The results showed that model-1, 2, and 3 give maximum yield of 760, 925, 320 ml/m 2 of distilled water with maximum thermal and exergy efficiency of 17.15 % and 0.6 %, 17.25 % and 1.1 %, and 7 % and 0.3 % respectively over seven hours span. This investigation also reveals the heat retaining capacity of SS and effect of polystyrene coverage on glass cover that helps to obtain maximum nocturnal yield of 435, 735, 320 ml/m 2 from model-1, 2, and 3 respectively on different days that make total distilled output to 1195, 1660, 560 ml/m 2 on a particular day. In design perspective, the proper selection of tilt angle facilitates the seamless gliding of condensate to collecting troughs that mitigate the loss of condensate that falls into the basin before reaching to trough.