Back Slope Research Articles

Spatiotemporal changes and background atmospheric factors associated with forest fires in Turkiye.

In this study, spatiotemporal analysis of forest fires in Turkiye was undertaken, with a specific focus on the large-scale atmospheric systems responsible for causing these fires. For this purpose, long-term variations in forest fires were classified based on the occurrence types (i.e. natural/lightning, negligence/inattention, arson, accident, unknown). The role of large-scale atmospheric circulations causing natural originated forest fires was investigated using NCEP/NCAR Reanalysis sea level pressure, and surface wind products for the selected episodes. According to the main results, Mediterranean (MeR), Aegean (AR), and Marmara (MR) regions of Turkiye are highly susceptible to forest fires. Statistically significant number of forest fires in the MeR and MR regions are associated with global warming trend of the Eastern Mediterranean Basin. In monthly distribution, forest fires frequently occur in the MeR part of Turkiye during September, August, and June months, respectively, and heat waves are responsible for forest fires in 2021. As a consequence of the extending summer Asiatic monsoon to the inner parts of Turkiye and the location of Azores surface high over Balkan Peninsula result in atmospheric blocking and associated calm weather conditions in the MeR (e.g. Mugla and Antalya provinces). When this blocking continues for a long time, southerly winds on the back slopes of the Taurus Mountains create a foehn effect, calm weather conditions and lack of moisture in the soil of Antalya and Mugla settlements trigger the formation of forest fires.

Multi‐mode gravity tectonics during northern North Sea rifting: the Snorre fault block case

AbstractContinental rifts are characterized by up to 30 km wide rotated fault blocks with stratigraphic dip away from the central rift axis. Although gravity‐induced mass movements are well known features of collapsed fault block crests, I here demonstrate the occurrence of polymodal gravity‐driven mass transport down the back slope of a first‐order rift fault block. I identify (1) early sliding related to syntectonic crestal collapse of second‐order rift faults, (2) large‐scale bed‐parallel sliding of the L‐M Jurassic sedimentary package, and (3) the accumulation of two 7 km long, 1–2 km wide and up to 750 m thick volumes of complexly slumped material in the hanging walls of two ramp‐forming faults. Early sliding is documented by 100 m of repeated Brent Group stratigraphy in a cored well in the study area (well 34/4‐15A). These smaller slides have intact internal stratigraphy but show elevated deformation band densities. The seismic data also show evidence for ca. 2 km of massive translational sliding of the ca. 400 m thick and ca. 300 km2 large Jurassic section above a lowermost Jurassic bedding‐parallel detachment. This translational slide did not deform much internally, except for ductile folding where it slid over underlying active rift faults. Chaotic seismic facies in fault hanging walls are interpreted as contorted Jurassic beds, formed by multiple slumping and sliding events that stacked mobilized sediments into a 750 m thick column. These complex slump volumes occur where fault displacement is highest along two relayed faults. A model is favoured where the large translational slide ruptured with an opening of space against the fault that was progressively filled with slumped material from the footwall. While the large‐scale translational sliding only caused moderate internal subseismic deformation, early sliding and, particularly, the complex slumping caused significant internal deformation. This study shows the importance of carefully searching for and distinguishing between different types of mass movement in rift systems.

Experimental study of internal solitary wave evolution beneath an ice keel model

Internal solitary waves (ISWs) propagating in polar seas are affected by the sea ice at upper boundary of seas and thus exhibit complex evolution characteristics. Herein, spatiotemporal changes in the wave element, flow field, and energy of ISWs beneath an ice keel model were investigated to examine the evolution of ISWs. For this purpose, laboratory experiments were conducted using dye-tracing labeling, conductivity probes, Schlieren technology, and particle image velocimetry. The results show that ice keel causes an increase in the thickness of the pycnocline and even the occurrence of breaking and internal surging of ISW. Additionally, the waveform becomes narrower or wider at different positions, and wave amplitude and speed decrease, with a maximum reduction 30%–40%. Furthermore, the ice keel strengthens the shear of the ISW-induced flow field, generating vortices and mixing. The energy of ISWs undergoes internal conversion majorly at the front slope of the ice keel, while energy dissipation occurs largely at the back slope, with dissipation rates as high as 60%.

Low-cost dehydrated starter production: Protective effect of maize-based carrier materials and its application in a Cameroonian maize-based traditional fermented beverage (Sha'a)

The objective of this work was to produce a dehydrated starter from Saccharomyces cerevisiae LT16 and Nakaseomyces delphensis LT80 and to evaluate its impact on the quality of Sha'a, a straw-colored or yellowish, milky, alcoholic or non-alcoholic beverage, made exclusively from maize For this purpose, a suspension of each strain was added to the carrier material (maize flour, husks and starch), dehydrated at 40 °C and then stored at 4 °C and room temperature, and the viability of the strains was assessed for 90 days. Sha'a was produced by both the pure and co-fermentation in which the kinetic parameters were determined. The consumers' appreciation was assessed. The highest viabilities after dehydration were 80.58 and 70.47 % for LT80 and LT16 respectively in maize flour. However, after 90 days, viability was higher in maize flour (68.60 % at 4 °C and 62.04 % at room temperature for LT80 and LT16 strains respectively). As a stress marker, only glutathione was positively correlated with viability. In addition, the fermentation efficiency were negatively affected by drying. The strain LT80 significantly (p < 0.05) increased the palatability of the Sha'a. Sha'a produced with LT80, LT80+LT16 starters and the back slope were “quite pleasant”. Therefore, the LT80, LT80+LT16 starters would be of interest to standardise, guarantee hygienic and sensory quality, and meet consumer demand.

A Variety of Transformations of Nonlinear Internal Tidal Waves of the Northwestern Shelf of Australia

Highly nonlinear internal waves at the continental margin on the northwestern shelf of Australia are discussed using detailed velocity and temperature time series recorded from moored current meters over 67 days. The region is characterized by a vigorous semidiurnal inland tide that propagates towards the shore along the shelf. In this area, an increase in the internal tide and the formation of bore-like formations, often accompanied by internal solitary waves, are observed. The frequency spectrum of the internal waves is presented, calculated from the records of the current component directed along the normal to the coast. Within the framework of this work, we have focused on analysis of the shape and properties of the internal tide. As a result, five different types of waves are distinguished. They consist of bores on the front or back sides of the wave, “square” waveforms with bores on both the front and back sides of the wave simultaneously, as well as small- and large-amplitude linear waves. The statistics of transformations of the types of internal tides during their propagation along the route section from the slope to the shelf is given. The main types of waves propagating without transformation and short-lived waves, which include “square” tidal waves and waves with bores on the back slope of the wave, are revealed. In general, the analysis provided an accurate account of the present-day nonlinear transformations of tidal internal waves on the Northwestern Australian Shelf.

CFD Investigation for Sonar Dome with Bulbous Bow Effect

The objective of this study is to design a hull-mounted sonar dome of a ship using OpenFOAM with a bulbous bow effect at cruise speed in calm water. Verification and validation for the original sonar dome simulation are conducted. Next, the 1.44 million grid size is selected to study different dome lengths. By protruding the dome forward 7.5% of the ship’s length, the optimal 17% resistance reduction is achieved and is mainly caused by the pressure resistance decrease. The optimal sonar dome not only functions in the same way as a bulbous bow, but the viscous flow behaviors are also improved. The protrusion corresponding to 90 deg phase lag reduces the bow wave amplitude. The flow acceleration outside the boundary layer and ship wake velocity are higher coinciding with the much lower total resistance. A smaller flow separation and thinner boundary layer are also observed behind the sonar dome because its back slope is less steep. The high pressure covers a smaller area around the bow, and the smaller bow wave crest does not hit the ship’s flare to form high pressure. Consequently, the lower high pressure on the dome front and higher low pressure on the dome back result in the decreases in pressure resistance. The vortical structures are also improved.

Characterizing safe sites for seedling establishment of endangered Arctomecon humilis Coville in a warm desert gypsum environment

Plant species endemic to gypsum occur in arid and semiarid regions worldwide and are an important component of biodiversity conservation, but gypsophile habitat selection within more arid gypsum environments remains largely unexplored. Our goal in this study was to inform efforts to introduce new populations of the endangered Mojave Desert gypsophile Arctomecon humilis Coville (dwarf bear poppy) through direct seeding at more remote locations that are less impacted by threats associated with urban expansion. We characterized approximately 600 ‘safe sites’ where seedlings of this species had recently established and examined distribution of these safe sites across habitats on the gypsum cuesta landscape. Using drone imagery at the landscape scale, we found that juveniles showed an even stronger preference for the white surface cover class than adults and were also markedly under-represented in the dark crust cover class. Two-thirds of the juveniles were found on knoll tops and upper back slopes, while only 3% were found on bottoms. At the plot scale, most juveniles were associated with surfaces where lichen crust and white gravel occurred in a fine-scale mosaic. At the emergence microsite scale, two-thirds of the seedlings had emerged from narrow gaps between two or more contact substrates, most often lichen crust and gravel. Even when seedlings emerged from lichen crust alone, emergence was usually from a gap and not from the surface of intact lichen thallus. On bottoms, toe slopes, and lower back slopes where dark lichen crust is often heavy and continuous, very few juveniles were found. Fewer than 7% of juveniles were found in direct association with living adults, likely because of adaptations for both enhanced seed dispersal and a persistent seed bank. There was also no evidence for establishment facilitation by nurse plants of other species. These results are contrasted with gypsophile establishment ecology in less arid environments. They also enable drone-based screening at the landscape scale as an efficient first step in selection of introduction sites.

A VARIETY OF TRANSFORMATIONS OF NONLINEAR INTERNAL TIDAL WAVES ON THE NORTH-WEST AUSTRALIAN SHELF

Highly non-linear internal waves at the continental margin on the northwest shelf of Australia are discussed using detailed velocity and temperature time series recorded from moored current meters. The region has a vigorous semidiurnal inland tide that propagates towards the shore along the shelf. In this area, there is an increase in the internal tide and the formation of bore-like formations, often accompanied by internal solitary waves. In this paper, the emphasis is on the analysis of the shape and properties of the internal tide. The frequency spectrum of internal waves is presented, calculated from the records of the current component directed along the normal to the coast. Five different types of waves are distinguished, which consist of burrs on the front or back side of the wave, “square” waveforms with a bores on both the front and back sides of the wave at the same time, as well as linear waves of small and large amplitude. The statistics of transformations of the types of internal tides during their propagation along the section of the route from the slope to the shelf is given. The main types of waves passing without transformation and waves with a short lifetime, which include “square” tidal waves and waves with bores on the back slope of the wave, are revealed. In general, the analysis showed a real picture of the ongoing nonlinear transformations of tidal internal waves occurring on the north-west shelf of Australia.

The relation between body surface angle and apparel ease distribution under the motion state

PurposeThe purpose of this paper investigates dynamic ease distributions of clothes at bust and waist lines with different body surface angle by using a Qualisys three-dimensional motion capture system (3DMCS).Design/methodology/approachThe current method first obtain the specific markers of participants and their clothes along the bust and waist lines through 3DMCS, then using the least square method and four piecewise polynomial fitting participants and their clothes' bust and waist curves. The coordinates of the markers were tracked by the 3DMCS, while the participants under different body surface angle walked on a treadmill calculated the distances of markers coordinates to the participants' bust and waist curves. Finally, the data of samples were analyzed. It was found that the dynamic ease distributions showed different patterns at different body surface angle.FindingsThe results revealed the bust convex angle is 26.53 degrees (Specification:X3) and back slope angle is 13.96 degrees (Specification: Y1), the fluctuation of participant ease distributions on bust section was most obvious, and the maximum fluctuation value was ±20 mm and ±25 mm. The ease distributions of participant waist section fluctuated most obviously when the bust convex angle is 28.10 degrees (Specification: X5) and the back slope angle is 13.96 degrees (Specification: Y1), and the maximum fluctuation was ±30 mm and ±20 mm. The bust convex angle has the greatest influence on 1# garment, and the back slope angle has the greatest influence on 2# garment.Originality/valueCurrently, there is little information in the literature about dynamic ease distributions of garment on a different body types. This paper takes different body surface angles as the research objects to analyze the ease distributions of different clothes, the conclusion can provide reference data for 3D garment modeling and improve the authenticity of virtual garment fitting.

Assessment of the impacts of land-use change and slope position on soil loss by magnetic susceptibility-based models

Soil loss is a global environmental problem resulting from the erosion process caused by many factors, including land use and slope position. Estimation of total soil loss from agricultural fields is useful for understanding the consequences of historical and current erosion. The main purposes of the current study are to explore the application of magnetic measurements in the mapping and measuring soil redistribution in cultivated (MZ13) and forested (MZ17) transects in a Moroccan subcatchment, to develop a methodological approach correlating magnetic susceptibility (MS, denoted χ) variation to soil erosion/aggradation, and to discriminate the effects of land-use change and slope position on the total cumulative soil loss, assessed using three recently established erosion models based on an MS parameter. MS measurements were done on several soil cores collected at different slope positions including the summit (SU), shoulder (SH), back slope (BS), foot slope (FS), toe slope (TS) for Transects MZ13 and MZ17. A tillage homogenization (T-H) model, simple correlation model (SCM), and simple proportional model (SPM) based on χlf (where lf indicates low frequency) were applied to estimate soil loss for each slope position in the two transects. The results show that the correlation between χlf and χfd (which is the frequency-dependent magnetic susceptibility percentage) is positive and high for the two transects (R2 = 0.95; p < 0.01). The results confirm that the χlf enhancement of soils selected in calcareous parent material is related to the pedogenic processes with the formation of superparamagnetic particles distributed along the slope positions. The current study proves that it is possible to trace and monitor soil erosion and deposition using magnetic parameters (χlf and χfd%) for different slope positions along cultivated and forested transects. The results confirm that the soil losses strongly depend on land use and slope position. Higher erosion depth (d) estimated using the three erosion models are comparable and were about d(T-H, BS17L) = −154.9 cm, d(SCM, BS17L) = −142.3 cm, and d(SPM, BS17L) = −143.6 cm for MZ17 Transect, and about d(T-H, FS13M) = −156.3 cm, d(SCM, TS13L) = −143.8 cm, d(SPM, FS13M) = −145.9 cm for MZ13 Transect. The applied models indicate that the strong losses take place in the upper and lower slopes of the cultivated transect, and in the middle and lower slopes of the forested transect.

Study on fracture development and progressive failure characteristics of downstream dam-type expansion tailings reservoir

With the economic development and industrialization, the increasingly accumulated tailings ponds in China have become a great risk. Due to the difficulty of selecting proper site for a new reservoir in Yunnan, a sub-dam was built at the downstream original reservoir. This study explored the fracture development and progressive failure characteristics of the tailings reservoir area after capacity expansion based on a similarity experiment and the numerical simulation. The results showed that the primary cracks in the reservoir area were more than those at the top of the sub-dam. With the increase of the upper load, the primary cracks further developed and penetrated the whole sub-dam top, and the sub-cracks were then produced under the concentrate stress of the primary cracks. After the further development of the sub-cracks, the secondary cracks parallel to the primary cracks were formed on the outer slope of the sub-dam. The progressive failure of a tailings dam can be summarized as: the maximum shear stress was firstly generated at the toe of the slope or the top of the dam which then extended to the top of the sub-dam in the form of a curve and finally formed the failure surface by connecting with the primary fracture of the tensile plastic zone at the top of the dam. The study also found that in the process of tailings accumulation in the new reservoir area, tailings would form "back pressure slope protection" at the initial dam of the original reservoir, which not only effectively delayed the occurrence of shear failure, but also inhibited the generation and penetration of tensile plastic zone.

Prospects of sediment deposition at small watershed scale in the black soil region of Northeast China: A mini review

Sediment deposition is one of the most significant processes in small watersheds characterized by gentle long hillslopes in the black soil (Mollisol) region of Northeast China, as indicated by severe ephemeral gully and gully erosion on hillslopes and very low sediment concentrations in river systems. Few reviews have been conducted to summarize the related research in this region. The objectives of this review were to identify the potential factors influencing sediment deposition, review related studies, and propose future research needs in the black soil region of Northeast China. Sediment deposition is controlled by the deficit between sediment transport capacity of flow and sediment load. Hence, all factors affecting flow transport capacity and sediment load directly affect sediment deposition. For a specific small watershed, the change in slope gradient along the flow path is the key factor affecting sediment deposition. Shelterbelts, ridge tillage systems, terraces, grass strips, road distribution, ponds and reservoirs, and land-use patterns also influence the spatial distribution and rate of deposition. The trace method has been widely used to quantify sediment deposition in this region. The results of cesium-137 (137Cs), lead-210 (210Pb), and magnetic susceptibility reveal that serious deposition occurs on the back and foot slopes. Distinct deposition occurs in front of contour shelterbelts. Future studies should focus on the methodology, spatial and temporal variations, dominant influencing factors and their mechanisms, and the potential effects on land productivity within specific small watersheds and across the black soil region. This review provides insights into the sediment deposition process in small watersheds characterized by gentle, long hillslopes.

Flash flooding on Mars could be linked to large fault slip events

Studies of Martian fault-related landform morphology have noted an interesting phenomenon associated with large thrusts — isolated channels that run from the crests of these landforms down their slopes. One such example is Ogygis Rupes, an east-verging, 180 km long thrust-fault-related landform located near 55°W, 33°S. Geometric modeling efforts have indicated the fault underlying this landform has experienced approximately 2850 m of slip, and a large anticlinal fold has grown above the fault. We mapped 72 channels on back and front slopes of this massive landform at 1:24,000 scale on 10 mosaiced Context Camera images (6 m/pixel) and one High-Resolution Imaging Experiment image (2.5 m/pixel). The morphology of these channels indicates that they formed through flash flood events that originated near the hinge of the fold. We propose that these flooding events were due to the melting of subsurface ice during fault slip. We apply a thermodynamic model for heat generation along the fault surface during slip events of various magnitudes to estimate the volumes of water produced during each hypothetical event. By comparing these estimates to channel discharge values estimated from channel morphologies, we resolve fault slip magnitudes that could produce the channels. We find that slip events of approximately 28 m produce enough heat to melt the ice associated with channel flow (4.867 × 109 m3). This estimate is based on slip within a 1 m basaltic fault zone, with a friction coefficient of 0.6 where all pore space is occupied by water ice. Results indicate that only mature faults with well-developed, fractured hinges are capable of both (1) melting enough subsurface ice and (2) transporting the water to the surface to result in flooding, explaining why this impressive phenomenon remains a rare but important hazard of which to be aware during planning of the exploration and settlement of Mars.

Sonar Dome Geometry Design Using CFD to Reduce Ship Resistance at Cruise Speed.

The objective of this study is to design the hull-mounted sonar dome of a ship. The goal is to reduce the ship total resistance and improve the flow field around the sonar dome for the ship design speed. OpenFOAM 6 was applied to analyze the viscous flow around the ship bow and then optimize the sonar dome geometry. The length, width and depth of the original geometry were maintained. Only the local geometry was fine-tuned considering the back slope and front tip by using Rhinoceros 6. The verification and validation was performed for the original hull form against towing tank resistance data. The grid independence was checked for the optimal design in different design stages. To ensure less influence on the interior equipment installation and to be able to re-use the non-steel dome part, the best resistance reduction is almost 2%. With a larger allowance of shape deformation, the maximal reduction could reach slightly higher than 3%. The flow field is improved for smaller flow separation and vortex, and less fluid nose in sonar detection is expected. The main reason of the resistance reduction is the decrease of the pressure component. In conclusion, a sonar dome design procedure is proposed, and an optimal geometry is suggested.

Proximate and Mineral Composition of Aerial Potato (Dioscorea bulbifera Linn) after using Different Fermentation Methods

This study evaluated the nutritional value of aerial yam potato fermented with different methods and other food processing. Aerial potato was subjected to different treatments (peeled, unpeeled, peeled and blanched, unpeeled and blanched, peeled and boiled, unpeeled and boiled) before fermentation with different methods like submerged fermentation and back slope (BS) fermentation. The proximate and mineral compositions were monitored using standard methods. &#x0D; Crude Protein (%) of the peeled aerial potato significantly increased from 4.12 ±0.13 at the initial to 10.11±0.85 at the end of the fermentation while unpeeled aerial potato slightly increased from 3.66a±0.04 at the initial to 4.19±0.03 at the end of the fermentation. Peeled and blanched; unpeeled and blanched as well as the unpeeled and boiled samples had the highest iron (0.143±0.01 ppm), magnesium (6.40±0.02 ppm) and calcium (6.32±0.03 ppm) contents in fermented aerial potato sample. Generally, the different of methods of fermentation employed improved the nutrient contents of fermented aerial potato.

Influence of Underground Mining Direction Based on Particle Flow on Deformation and Failure of Loess Gully Area.

Due to unique landform and lithological features of the loess gully area, the geological disasters caused by coal mining have become more complex. Moreover, the advancing direction of the working face has an important influence on the deformation of the slope on both sides of the gully. In this paper, combined with the specific conditions of a coal mine working face in western China, we use the method of particle flow numerical simulation and theoretical analysis to examine and observe the deformation, as well as characteristics of failures in the loess gully area under different mining directions of the working face. The deformation process of the gully area can be obtained by combining the numerical simulation results. According to different mining directions of the working face, the failure mode of mining in the loess gully area was divided into the back slope and along slope advancing failure modes. Through empirical evaluation, our investigation demonstrates that the bottom of the gully was damaged seriously by both along slope mining and back slope mining. Albeit the influence of coal seam excavation on the slope surface was relatively small; however, it is greater on the flat ground of the upper slope. Under the same mining conditions, the advancing direction of the working face affected the horizontal movement of the loess gully area but had less effect on the subsidence. Furthermore, we observed that the failure mode of the mining slope is highly correlated with the mining direction and relative position of the working face. The results obtained from this research can provide useful information for deformation and failure prediction, working face mining method, and geological disaster assessment in the loess gully area.

Geotechnical Stability Analysis of the Quay Wall of Military Port Ksar Sghir, Morocco

This article consists in establishing a geotechnical stability study of the -4m/zh quay belonging to the Ksar Sghir Port. First of all, using the TALREN software for verification against large slips. the study presents a verification of the stability for the rear slope slip circles and for the front slope slip circles in the static case. Secondly, stability was determined for the back slope slip circles and for the front slope slip circles in the seismic case. Moreover, PLAXIS software was used to model the displacements and constraints in the structure. Following the results of the safety coefficients, we notice that the stability of the structure gives acceptable values. In addition, the soil does not reach breaking stress. The total mean stress and total displacement mostly impacted the surface area that is related to external impact.

Studies on the Genesis of Soils in Jong River Basin in the Northern Province of Sierra Leone

The soil resources of Sierra Leone remain an integral part of sustainable agricultural development but knowledge of the suitability of soils and their management requirements for a variety of land uses is still lacking to a greater extent. In this view, a detailed soil survey of three chiefdoms in Northern Sierra Leone was undertaken to evaluate the genesis of soils and interpret soil-landscape properties and their relationships using the toposequence and free style approach of soil survey. Three major soil types, viz, gravelly, gravel-free over gravel and gravel-free soils, formed either directly or indirectly from weathered and disintegrated parent materials of two geologic origins namely Rokel River Series (comprising of sandstone, shale and mudstone), and Granite and Acid Gneiss were identified. The gravelly soils are formed from sandstone and sandy shales of the Rokel River Series, which upon weathering released iron and hydrated oxides that hardened into plinthite upon drying. The gravel-free over gravel soils are formed from acid gneiss containing acid and intermediate igneous and metamorphic rocks, which upon weathering produced sandy clay textured soils whereas the gravel-free soils are derived from sedimentary rocks (shales and mudstones) of Rokel River Series, which upon weathering and action of organisms produced sandy clay loam and sandy clay textured soils. The gravel-free over gravel soils are mostly located in the summit and back slopes and show dark brown to dark yellowish-brown hue and moderate chroma, weak to moderate structure and absence of coarse fragments in the 0 - 40 cm layer, and a strong brown hue and high chroma, very weak fine angular blocky structure having abundance of coarse fragments from 40 cm and above. In these soils, the compactness of ironstone and sandstone gravels increases with depth. The gravel-free soils are found on three landscape positions, viz, back slopes, foot slopes and toe slopes. On the back and foot slopes, the soils are characterized by very dark brown to dark yellowish-brown hue and high chroma, sandy loam to sandy clay texture, coarse angular to moderate sub-angular blocky structure and absence of coarse fragments throughout the horizon. In these soils, the clay content and sand grain sizes were observed to increase with depth. On the toe slopes, the soils show black to greyish-brown hue and low chroma, silty loam to sandy loam, structureless and high water holding capacity.

Caracterização e evolução de solos em vertentes assimétricas da Reserva Ecológica da Sapiranga - Tabuleiros Costeiros do Litoral Norte do Estado da Bahia

A análise integrada solo relevo é fundamental para entender a evolução das paisagens e subsidiar o planejamento e ocupação das terras, sobretudo em locais sob grande pressão da expansão urbana, a exemplo do Litoral Norte do Estado da Bahia. O presente estudo buscou compreender quais fatores comandaram o processo de podzolização e como teria evoluído o relevo em uma região dos Tabuleiros Costeiros Dissecados do Grupo Barreiras. A metodologia adotada, pautada na relação entre solos e relevos a partir da interpretação da morfologia de duas vertentes localizadas na Reserva Ecológica da Sapiranga, envolveu análises de imagens da área de estudo, trabalhos de campo, elaboração de catenas, análises laboratoriais e classificação de solos. Os resultados obtidos identificaram que, apesar de ambas as vertentes estarem localizadas sob condições climáticas semelhantes e apresentarem processos de podzolização, as dinâmicas deposicionais, geoquímicas e topográficas resultaram em configurações pedogeomorfológicas distintas. Assim, o topo da Vertente “A” apresenta um Neossolo Quartzarênico Órtico típico, possivelmente constituído por areias provenientes do retrabalhamento eólico de Leques Aluviais Pleistocênicos ou deposição fluvial do Rio Pojuca, sendo sucedido por um Espodossolo Ferri-Humilúvico Órtico típico, na meia vertente, e um Cambissolo Háplico Tb Distrófico típico, na baixa vertente, oriundo de sedimentos do Grupo Barreiras. Na Vertente “B” foi identificado um sistema de transformação pedológica Latossolo-Espodossolo, com Latossolo Amarelo Distrófico psamítico na alta vertente, seguido por um Espodossolo Humilúvico Órtico arênico que, por sua vez, é sucedido por um Espodossolo Humilúvico Órtico típico. O estudo concluiu que a área de estudo apresenta uma atual configuração pedogeomorfológica resultante de reativação neotectônica e podzolização.Palavras-chave: Latossolos, Neossolos Quartzarênicos, Espodossolos, catena, vertente. Description and evolution of soils in asymmetrical slopes at Sapiranga’s Reserve, Coastal Tablelands of Bahia A B S T R A C TIntegrating soil and relief contribute to the understanding of the evolution of landscapes and subsidize the planning of use and occupation of lands, mainly in places under urban sprawl, as Northeast Coast of Bahia. This work looked for understand the factors that promoted the podzolization and how part of the Coastal Tablelands’ relief may had evolved. To reach those goals, analysis of images of the study area were made, followed by fieldwork, elaboration of two catenas, classification of soils and physical and chemical laboratory analysis. Despite being located under similar climate conditions and present common podzolization processes, both slopes present very distinct pedogeomorphological conformations, resulted of depositional, geochemical and topographical dynamics. Therefore, the slope “A” presents in its summit a Arenosol, a soil constituted by white sand that is possibly the result of the eolian rework of Pleistocene-age alluvial fans or fluvial deposition of Pojuca river, being succeeded by a Podzol, in the back slope, and by a Cambisol, in the foot slope, arising from sediments of the Grupo Barreiras. In the slope “B” was identified a pedological transformation system from Ferralsol to Podzol. Thus, in the summit is present a Ferralsol, succeeded by a Podzol, which is succeeded by a Podzol again. This work demonstrates that the study area shows a current pedogeomorphological set resulted of neotectonic reactivation and podzolization.Keywords: Lateritic Soil, Arenosol, Podzol, Catena, Slope.

Stability Analysis of Downstream Dam Expansion Tailings Pond

The buildup of tailings in China has expanded dramatically with economic development and industrial demand, and the safety of tailings reservoirs has become increasingly serious. Due to the difficulty in finding a new reservoir site, the expansion approach of building a new tailings dam downstream of the original reservoir area was investigated. The stability of the tailings reservoir after expansion was calculated using the traditional dynamic and static stability solution method and taking into account the unpredictability of dam construction materials and tailings material parameters in the reservoir area. The results reveal that throughout the tailings accumulation process in the new reservoir, the tailings will build a back pressure slope at the original reservoir’s initial dam, which can considerably improve the original reservoir’s dynamic and static stability. The Monte Carlo method clearly outperforms older methods for tailing pond stability analysis. The results of this paper’s calculations will give a theoretical foundation and practical reference for the later management and maintenance of such tailings reservoirs, as well as fresh ideas and insights for comparable projects due to limited site selection.