Sloping Ground Surface Research Articles

Oil spills characterization and modeling using remote sensing and geophysical techniques to protect the highly vulnerable coastal zones in Alexandria, Egypt

Nowadays, oil spills threaten both aquatic and terrestrial environments, especially in regions with intensive oil refining and shipping activities and high environmental sensitivity, such as Alexandria city, Egypt. Oil spill characterization in coastal populous cities is particularly difficult due to large chemical/physical soil heterogeneities and saltwater intrusion, which represent a major challenges for soil remediation and restoration. Recently, the development of inversion algorithms enables electrical resistivity imaging (ERI) to perform detailed characterization of near-surface soil pollution. The study implements an interdisciplinary approach using remote sensing and an advanced time-lapse 2D-inversion scheme for detailed characterization of oil spill patterns around oil refinery sites in the Alexandria coastal zone. The implemented scheme was able to improve the depth of investigation while maintaining the shallow lateral model resolution. The findings indicate that the mapped oil spills constitute a wedge-like form where the oil moves gradually downward, and it then shifts horizontally towards the shoreline with thinning in oil-contaminated zones under control of tidal action and ground surface slope. Consequently, guided by remote sensing observations, in-situ trenches/wells are suggested to withdraw the oil-contaminated water at the maximum deduced oil-contaminated soil thickness. The applied procedures in this study are replicable and can be effectively used as a pre-requisite to remedy oil spills along terrestrial coastal environments worldwide.

A Seismic Site Factor Adjustment Framework for Sloping Grounds and Its Application to Charleston, South Carolina

ABSTRACT Ground motions and seismic site factors for the design and analysis of infrastructure systems are typically computed based on one-dimensional (1-D) site response analysis, assuming the ground surface is horizontal and the earthquake waves propagate vertically near the ground surface. The 1-D results may not be applicable for sloping ground surfaces and layer interfaces, and therefore, the 1-D results must be adjusted for sloping grounds. In this study, a general framework for developing seismic site factors for sloping grounds and its application for Charleston, SC is presented. The two-dimensional (2-D) site response analysis results of sloping ground were compared with the 1-D horizontal ground results to develop slope adjustment factors. A total of 385 2-D nonlinear finite element simulations of sloping grounds were performed considering seven ground inclinations, 11 shear wave velocity profiles, and five ground motions representative of the area. The results show that the surface responses computed from sloping ground analyses significantly differ from those of horizontal ground analyses. By comparing the 1-D and 2-D results, a set of slope adjustment factors was developed and expressed as an easy-to-use chart. The slope adjustment factor at a project site can be obtained from the proposed chart using site-specific VS30 and ground inclination at a selected period.

Behaviour of a laterally loaded rigid helical pile located on a sloping ground surface

Offshore wind turbines, crucial for electricity generation worldwide, face challenges from strong winds, waves, and uneven ocean floors. To address these issues while remaining cost-effective, an innovative foundation is essential. The study introduces a helical monopile with a circular helix made of the same material as the shaft, representing a significant advancement. The study employs both 1 g model experimental tests and numerical simulations (PLAXIS 3D) to explore how changing slope conditions, pile positions, and the inclusion of the helix affects the response under monotonic lateral loading. Factors studied include ground slope angles (flat, 1 V:5H, 1 V:3H, 1 V:2H, and 1 V:1H), pile positions along the slope (c = 0Dp, 2.5Dp, 5Dp, and 7.5Dp), and variations in the number and positions of the helix (Hp) (0.25Lp, 0.5Lp, and 0.75Lp). The investigation involved analyzing the spacing between helices about both the length of the pile (Lp) and the diameter of the helix (dh ). The eccentricity to the diameter of pile ratio (e/Dp) is maintained as 12. The main objective is to compare the effectiveness of large-diameter helical piles to conventional monopiles in resisting upward and lateral forces. Results show helical piles offer a 100% improvement in uplift resistance and a 53% increase in lateral resistance compared to monopiles. This significant enhancement in capacity, particularly on sloping surfaces where monopiles typically exhibit reduced performance, underscores the effectiveness of helical piles in enhancing lateral capacity compared to monopiles.

Behavior of a Laterally Loaded Rigid Finned Pile Located on a Sloping Ground Surface

Behavior of a Laterally Loaded Rigid Finned Pile Located on a Sloping Ground Surface

3D-MFDNN: Three-dimensional multi-feature descriptors combined deep neural network for vegetation segmentation from airborne laser scanning data

Airborne laser scanning (ALS) is a state-of-the-art technique for fast and accurate three-dimensional information acquisition of land cover including vegetation. This paper presents a three-dimensional multi-feature descriptors combined deep neural network-based methodology (3D-MFDNN) for ALS data-based vegetation segmentation with three well-designed steps namely generation of feature descriptors, 3D-MFDNN method’s training, testing, and performance comparison using ALS datasets. The proposed 3D-MFDNN method is straightforward to implement, where accurate segmentation of tree points are effectively dealt in several complex cases, such as tree branches connected with other objects, tree with understory low vegetation, low-lying plants on the sloping surface, large tree with volumetric shape and branches hanging near sloping ground surface, etc. The method performance was evaluated using six datasets having different levels of scene complexity, and vegetation segmentation was performed at F1-score and accuracy of 83.94 % and 92.13 %, respectively. The method achieves significant improvement in comparison with several state-of-the-art methods.

Influence of edge distance on experimental p-y curves for piles near slope

ABSTRACT A series of 24 model laboratory tests had been performed to examine the pile response nearby the slope. The main objective of the study was to quantify the effect of the edge distance and relative density on the pile response in sloping ground with respect to level ground case. The ground slope had been maintained as 1 vertical to 1.5 horizontal for sloping ground conditions. Experiments had been performed with varying edge distances from 0 to 12 times diameter under three different relative densities as 25%, 52% and 72%. The pile response in horizontal ground condition had been acquired at the same relative density to enumerate the effect of the ground slope. The deflection and bending moment were considerably augmented for the sloping ground surface. However, values had been witnessed to decrease with the increase in the edge distance. An increase in the relative density resulted in a reduction in the pile response. A generalised p-y curve is being suggested for sloping ground conditions. Reduction factors are being reported to account for the slope effect. These can be applied to the initial stiffness and ultimate soil resistance of the p-y curve in the level ground case.

Seismic bearing capacity factor [formula omitted] for a rough strip footing on sloping ground

By using the Mohr-Coulomb (MC) yield criterion, the method of stress characteristics (MOSC) has been employed to compute the bearing capacity factor Nγ in the presence of horizontal pseudo-static earthquake inertial forces for a rough strip footing over sloping ground surface. Two different types of failure mechanisms (M1 and M2) were employed. Due to rigorousness of the adopted failure mechanism, the present analysis overcomes the limitation of the existing MOSC formulation available in literature. The solutions in all the cases have also been determined based on the finite elements limit analysis (FELA). The results from the two different analyses, including the failure mechanisms, were found to be very close with each other.

Experimental study on evaluating the lateral load capacity of raker pile in sloping ground

ABSTRACT A lot of uncertainty is associated with the behavior of pile foundations on the sloping ground due to factors like soil – pile interface and vague evaluation of pile bearing capacity. These constraints have a considerable impact on the extensive implementation of deep foundation on sloping ground. Comprehensive research studies were carried out on laterally loaded vertical piles on horizontal ground whereas only a limited number of studies have been conducted on the behavior of the laterally loaded raker-pile system on sloping sites. Therefore, to address this knowledge gap, the current investigative research paper aimed to study the results of a series of static lateral load tests were conducted in the laboratory on a single aluminium model raker pile embedded in loose sandy soil on 1V: 2H sloping ground. The loading directions were varied considering either forward (close to the slope) or reverse (away from the slope) loading for all pile positions. The influence of the sloping ground was quantified by measuring the pile response for horizontal ground conditions. It was observed that there is a significant increase in the displacement of the pile for the sloping ground surface compared to the horizontal ground. With an increase in the edge distance from the slope crest towards the embankment, a reduction in the pile displacement was observed. The optimum distance from the slope crest towards the embankment where the effect of slope becomes nullified under both forward and reverse lateral loads was determined as 10D (D – Diameter of the pile). From the obtained results, it was evident that in the case of the level ground and sloping ground with forward loading, the negative raker piles offer more resistance to lateral loads than vertical piles. In contrast, the positive raker piles endure the least lateral load with increasing inclination angle.

PERBEDAAN KEMAMPUAN TANAH DALAM MENAHAN AIR PADA BERBAGAI KELERENGAN LAHAN KOPI DI DAERAH SUMBERMANJING WETAN, KABUPATEN MALANG

Water is a natural resource that is very important because its existence is needed for living things, including plants that need water for their growth and development. The availability of water in the soil has different amounts because it is influenced by various soil properties in the land. Land that has a sloping ground surface, the movement of water that enters the ground does not only move vertically as in land that has a flat surface but also laterally is parallel to the sloping land surface and moves down the slope. The first land has a slope percentage of 6%, the second has a slope of 13%, the third has a slope of 23%, and the fourth has a slope of 37%. The study consisted of 4 treatments for different levels of a land slope, and nine replication points were carried out. The results of this study indicated that the difference in the level of slope in each land had an effect on the water content in the soil at a depth of 40-60 cm; the higher the percentage of the slope of the land reduced the availability of groundwater. Specific gravity, porosity, and soil meso pore had a significant effect on the soil water content with a positive correlation direction, meaning that the higher the density, porosity, and soil meso pores, the more water available in the soil. Macro pores and soil micro pores had a significant effect on soil water content with a negative correlation, meaning that the higher the macro pores and soil micro pores will reduce the available water in the soil.

Two-dimensional liquid water flow through snow at the plot scale in continental snowpacks: simulations and field data comparisons

Abstract. Modeling the multidimensional flow of liquid water through snow has been limited in spatial and temporal scales to date. Here, we present simulations using the inverse TOUGH2 (iTOUGH2) model informed by the model SNOWPACK, referred to as SnowTOUGH. We use SnowTOUGH to simulate snow metamorphism, melt/freeze processes, and liquid water movement in two-dimensional snowpacks at the plot scale (20 m) on a sloping ground surface during multi-day observation periods at three field sites in northern Colorado, USA. Model results compare well with sites below the treeline and above the treeline but not at a site near the treeline. Results show the importance of longitudinal intra-snowpack flow paths (i.e., parallel to ground surface in the downslope direction and sometimes referred to as lateral flow), particularly during times when the snow surface (i.e., snow–atmosphere interface) is not actively melting. At our above-treeline site, simulations show that longitudinal flow can occur at rates orders of magnitude greater than vertically downward percolating water flow at a mean ratio of 75:1 as a result of hydraulic barriers that divert flow. Our near-treeline site simulations resulted in slightly less longitudinal flow than vertically percolating water, and the below-treeline site resulted in negligible longitudinal flow of liquid water. These results show the increasing influence of longitudinal intra-snowpack flow paths with elevation, similar to field observations. Results of this study suggest that intra-snowpack longitudinal flow may be an important process for consideration in hydrologic modeling for higher-elevation headwater catchments.

Drainage Morphometric Investigation of Nimni Watershed, Chhatarpur District, Madhya Pradesh, India

The present paper deals with drainage morphometric investigation of Nimni watershed, Chhatarpur District, Madhya Pradesh, India. A morphometric analysis of the Nimni watershed has been carried out to characterize the nature of drainage network. The linear, areal and relief aspects of the drainage basin have been determined. The morphometric parameters have been computed on the basis of drainage map prepared on 1:50,000 scale. These parameters includes Stream order, Lengths of stream, Bifurcation ratio, Drainage density, Length of overland flow, Stream frequency, Form factor, Circulatory ratio, Elongation ratio, Lemniscate’s ratio, Basin relief, Relief ratio, Ruggedness number and Ground surface slope. The drainage area of the Nimni watershed is 98 km2. The stream order of the basin is mainly controlled by physiographic and lithological conditions of the area. The increase in stream length ratio from lower to higher order shows that the study area has reached a mature geomorphic stage. The geomorphic analysis of Nimni watershed reveals that the present drainage basin exhibits uneven topography, presence of hard rock terrain and dendritic to sub-dendritic drainage pattern. The dendritic drainage pattern exhibits the presence of hard and resistant rocks referable to Bundelkhand Granite Complex.

IMPACT OF LAND LEVELING AND CUT-OFF IRRIGATION ON COTTON YIELD AND WATER PRODUCTIVITY IN NORTH MIDDLE NILE DELTA REGION

A field trial was conducted through successive the two summer growing seasons 2018 and 2019 at Sakha Agricultural Research Station Farm, Kafr-El-Sheikh Governorate. The objective of this current study was to investigate the impact of three land leveling levels and three irrigation treatments on some water relationships, cotton yield and also some its components. The experiments were designed as split plot with three replications. The main plots were occupied by land leveling with three levels namely; traditional leveling farmers practices (L1), Dead level (0.0%) slope (L2) and 0.10% ground surface slope (L3). while sub plots were devoted t cut-off irrigation with three level namely, cut-off at 100% of furrow length (I1),cut-off irrigation at 90% of furrow length (I2) and cut-off irrigation at 80% furrow length(I3). The main results can be summarized as follows: Land leveling and cut-off irrigation treatments have highly significant effect on increasing the cotton yield. its components and fiber technological properties. The interaction between the two factors resulted in the highest values of cotton yield i.e. The highest mean values of seed cotton yield, boll weight, leaf area, plant height, lint percentage, lint index and seed index were obtained under I3 and L3 The highest mean values of fiber fineness, fiber strength, length 2.5%, length 50% and uniformity index were obtained from interaction between I3 and L3 . Cut-off irrigation at 80% from furrow length (I3) and 0.1%ground surface slope ( L3) decreased seasonal applied water, water consumptive use and water stored in the effective root zone by 20.11, 12.11 and 10.90%, respectively compared with cut-off irrigation at 100% of furrow length ( I1) and L1 (traditional land leveling). Also, the highest mean values of water application efficiency, water consumptive use efficiency (71.65, 67.84%) respectively were obtained with I3 and L3 treatments. The highest mean values of water productivity (WP) and productivity of irrigation water (PIW) were recorded under the I3 and L3.

Slope stability analysis using sheet pile reinforcement with the Bishop method

Slope is a sloping ground surface, and forms a certain angle to a horizontal plane and is unprotected. With non-horizontal soil conditions, a component of gravity will tend to move the ground down, so that landslides cannot longer be avoided. The location of this research is located at 150 KV substation, Payabungan. The selection of sheet piles as an alternative treatment is expected to minimize the occurrence of landslides at the substation, where if there is landslide at that location will have an impact on the power outages that will disrupt the activities of residents around. This research was conducted with Bishop’s analytical method, aiming to determine the safety factor of the slope before and after reinforcement. In this analysis, sheet pile reinforcement is done with three conditions. From the calculations obtained the value of the safety factor using the Bishop method obtained by 1.11. The value of the safety factor under conditions 1, 2 and 3 was 1.45; 1.50; 1.58. From this study, it was concluded that adding sheet pile as reinforcement would increase the value of the safety factor in order for the slope to be stable compared to the slope without any reinforcement.

Comparative lateral load field tests on straight-sided and belled piers in sloped ground

Comparative lateral load field tests were conducted on two straight-sided and two belled piers in a natural arid loess sloping ground with an inclination angle of 20° in the western Chinese Loess Plateau. The pier-head displacements, sloping ground surface deformations and soil pressure distributions were measured. The lateral load–displacement curves of the straight-sided and belled piers in the sloping ground generally exhibited the same three-phase non-linear behaviour, and their performances were similar to those of laterally loaded drilled shafts in horizontal ground. The ‘interpreted failure load’ of the laterally loaded piers in sloping ground was obtained using the representative lateral interpretation criteria and their extensions. Compared with the normalised lateral load–displacement curves of the drilled shafts in horizontal ground under drained and undrained lateral loadings, the displacement required to completely mobilise the lateral resistance for piers in sloping ground was much smaller. It was found that the use of belling can cause greater load transfer depths and can effectively mobilise more soil to resist lateral load. In addition, for both straight-sided and belled piers, an additional embedment of the shaft in sloping ground can increase lateral resistance to match the level-ground lateral capacity.

Spatially-integrated estimates of net ecosystem exchange and methane fluxes from Canadian peatlands

BackgroundPeatlands are an important component of Canada’s landscape, however there is little information on their national-scale net emissions of carbon dioxide [Net Ecosystem Exchange (NEE)] and methane (CH4). This study compiled results for peatland NEE and CH4 emissions from chamber and eddy covariance studies across Canada. The data were summarized by bog, poor fen and rich-intermediate fen categories for the seven major peatland containing terrestrial ecozones (Atlantic Maritime, Mixedwood Plains, Boreal Shield, Boreal Plains, Hudson Plains, Taiga Shield, Taiga Plains) that comprise > 96% of all peatlands nationally. Reports of multiple years of data from a single site were averaged and different microforms (e.g., hummock or hollow) within these peatland types were kept separate. A new peatlands map was created from forest composition and structure information that distinguishes bog from rich and poor fen. National Forest Inventory k-NN forest structure maps, bioclimatic variables (mean diurnal range and seasonality of temperatures) and ground surface slope were used to construct the new map. The Earth Observation for Sustainable Development map of wetlands was used to identify open peatlands with minor tree cover.ResultsThe new map was combined with averages of observed NEE and CH4 emissions to estimate a growing season integrated NEE (± SE) at − 108.8 (± 41.3) Mt CO2 season−1 and CH4 emission at 4.1 (± 1.5) Mt CH4 season−1 for the seven ecozones. Converting CH4 to CO2 equivalent (CO2e; Global Warming Potential of 25 over 100 years) resulted in a total net sink of − 7.0 (± 77.6) Mt CO2e season−1 for Canada. Boreal Plains peatlands contributed most to the NEE sink due to high CO2 uptake rates and large peatland areas, while Boreal Shield peatlands contributed most to CH4 emissions due to moderate emission rates and large peatland areas. Assuming a winter CO2 emission of 0.9 g CO2 m−2 day−1 creates an annual CO2 source (24.2 Mt CO2 year−1) and assuming a winter CH4 emission of 7 mg CH4 m−2 day−1 inflates the total net source to 151.8 Mt CO2e year−1.ConclusionsThis analysis improves upon previous basic, aspatial estimates and discusses the potential sources of the high uncertainty in spatially integrated fluxes, indicating a need for continued monitoring and refined maps of peatland distribution for national carbon and greenhouse gas flux estimation.

Improving Irrigation Efficiencies through Different Methods of Land Leveling and Irrigation Discharge under Using Gated Pipes at North Delta

A field trial was conducted through summer season of 2016 at Sakha Agricultural research Station Farm, Kafr El-Sheikh Governorate. The purpose of the study was to investigate the effect of four methods of land leveling (traditional land leveling, precision land leveling, ground surface slope of 0.05% and 0.1% as main plots and three irrigation water discharge (2.0, 2.5 and 3.5 L.Sec-1 m-1) as sub plots on cotton yield and its components, some water relations and irrigation efficiencies. The results revealed that the ground surface slope of 0.1% and 0.05% and precision land leveling lead to increasing the seed cotton yield by 21.8, 15.12 and 5.15% compared to traditional land leveling, respectively. Also, irrigation water discharge at 2.5 and 3.5 L.Sec-1 m-1 raised seed cotton yield by 11.61 and 5.13% compared to 2.0 L.Sec-1 m-1. The achieved results indicated that the land leveling of ground surface slope of 0.1% and irrigation 2.5 L.Sec-1 m-1 were the best treatment in increasing the boll weight and earliness percentage. Respecting to irrigation water saving, data demonstrated that the land leveling at 0.1% and 0.05% ground surface slope saved irrigation water by 33.57% and 21.93% compared to traditional land leveling. Data indicated that the interaction between land leveling and 0.1% ground irrigation water discharge at 3.5 L.Sec-1 m-1 obtained the highest values of water distribution efficiency, water application efficiency, consumptive use efficiency, water productivity and productivity of irrigation water.

Analysis of laterally loaded group of piles located on sloping ground

In this paper, a finite element numerical analysis was carried out to study the behaviour of group of piles located on sloping ground using finite element analysis software PLAXIS 3D. A pile of 0.305 m diameter and 9.1 m length was arranged in 3 × 3 group pattern with spacing equal to three times the pile diameter (3D) and was modelled by PLAXIS 3D. The group of piles was embedded into a soil profile consisting of soft to medium-stiff clay and silts underlain by sand. A parametric study was carried out to study the behaviour of group of piles located on sloping ground surface (1V:5H and 1V:3H slopes) and subjected to lateral loads. The effect of slopes on pile capacity, the behaviour of lateral deflections and bending moment profile of front, middle and back rows of group of piles were studied.

Effect of Slope on p-y Curves for Laterally Loaded Piles in Soft Clay

Pile foundations are often subject to lateral loading due to various forces on a variety of structures like high rise buildings, transmission towers, power stations, offshore structures and highway and railway structures. The present investigation is to study the effect of slopes on p-y curves (where p is the static soil reaction and y is the pile deflection) due to static lateral loading in soft clay (Consistency index Ic = 0.42). A series of laboratory model tests were carried out on the instrumented model pile on sloping ground (slopes of 1V:1H, 1V:1.5H, 1V:2H, 1V:3H and 1V:5H) and with varying embedment length to diameter ratio (L/D) of 20, 25 and 30. From the experimental results, the bending moment curves along the pile shaft are double differentiated to obtain the soil resistance (p) and double integrated to obtain the deflection (y) using curve fitting method. New p-y curves for piles located on crest of soft clay with different sloping ground surface under static lateral loading are developed. Moreover, the effect of sloping angles on proposed p-y curves was studied.

Uplift capacity of horizontal strip plate anchors adjacent to slopes considering seismic loadings

For computing the uplift capacity of strip anchors buried adjacent to sloping ground surface in the presence of pseudo-static earthquake body forces, theoretical solutions have been developed by using the upper bound theorem of limit analysis based on a simple rigid wedge collapse mechanism. The influence of the ratio of anchor edge-distance from the crest of slope to the width of anchor (ε) and earthquake acceleration coefficients (kh, kv) on the dimensionless seismic uplift factor (fγ) due to soil unit weight have been examined for different combinations of the internal friction angle of soil (ϕ), slope angle (β), and the embedment ratio (λ) of anchors. The magnitude of fγ was found to decrease continuously with increases in the slope angle and earthquake acceleration coefficients; whereas, as expected, fγ increases with increases in the soil friction angle, edge-distance ratio (ε) and the embedment ratio of anchors. Under the static condition, the angle of slope has no influence on the magnitude of uplift resistance when ε≥λtanϕ. The present solutions are in good agreement with the results reported in the literature.

Diurnal variations of temperature as a cause of periodic variations of high-frequency geoacoustic emission

Investigated is the periodic component of geoacoustic emission within the frequency band from 2.0 to 6.5 kHz registered by the piezoceramic hydrophone installed near the bottom of Lake Mikizha in the Kamchatka Peninsula. It is revealed that the variation period is 24 hours and the maximum variation is observed in summer, when the average daily air temperature is above 10°C. In that period the close connection is revealed between the series of air temperature and geoacoustic emission. Taking into account the similar results of measurements of the ground surface slope at the observation site, the most probable reason for the diurnal variations of high-frequency geoacoustic emission is the deformation of near-surface sedimentary rocks caused by diurnal variations of temperature.