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The installation of many pile foundations near slopes inevitably exposes them to the influence of the slopes on the stiffness and strength of the soil–pile system, which is a significant issue involving geomechanics and worthy of concern. Therefore, a modified failure wedge model with an optimal base angle is developed to address the impact of slopes on laterally loaded piles in sand, drawing insights from previous experimental results and finite-element analyses. The objective of this model is to provide a more comprehensive and universal analysis of the lateral behavior of piles while considering a limited height slope, compared with previous models applicable in relatively limited cases. In this modified model, factors such as edge distance from the slope crest and slope height are taken into consideration. The proposed theoretical method demonstrates its capability to accurately predict the lateral response of a pile. Based on this method, an analysis is conducted to examine how slope inclination, edge distance from the slope crest, and slope height affect the soil–pile system. [ABSTRACT FROM AUTHOR]

The incoming solar radiation arriving the Earth's surface is strongly influenced by surface terrain. Conventional global weather forecast models, with grid scales of about 10 km, lack the resolution to accurately capture terrain-induced variations. We devised a new parameterization method to incorporate high-resolution subgrid-scale terrain data into grid-scale radiative flux calculations without averaging or smoothing topographic features. Utilizing a 15″ digital elevation model from the Shuttle Radar Topography Mission, we computed subgrid-scale data and transformed them onto the Korean Integrated Model's cubed sphere grid using a Voronoi diagram to maintain geographical accuracy. The new scheme was initially evaluated through offline ideal tests and case studies. The results demonstrated that the scheme accurately captured the variations in downward shortwave flux, keeping the mean flux on a global scale nearly constant. The global mean flux difference in all skies was less than 0.01%. Statistical analyses demonstrated improved temperature and geopotential height predictions compared to reanalysis data. The anomaly correlation coefficient for East Asia at 850 hPa increased by 0.036 at 240 forecast hours. Overall, the anomaly correlation coefficient and root mean square error of geopotential height and temperature showed enhancements, particularly in the Northern Hemisphere and tropics. Importantly, the scheme introduces negligible additional memory and CPU requirements, making it suitable for both regional and global models. Only a 0.58% increase in CPU time was observed for the 10-day forecast. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The incoming solar radiation arriving the Earth’s surface is strongly influenced by surface terrain. Conventional global weather forecast models, with grid scales of about 10 km, lack the resolution to accurately capture terrain-induced variations. We devised a new parameterization method to incorporate high-resolution subgrid-scale terrain data into grid-scale radiative flux calculations without averaging or smoothing topographic features. Utilizing a 15″ digital elevation model from the Shuttle Radar Topography Mission, we computed subgrid-scale data and transformed them onto the Korean Integrated Model’s cubed sphere grid using a Voronoi diagram to maintain geographical accuracy. The new scheme was initially evaluated through offline ideal tests and case studies. The results demonstrated that the scheme accurately captured the variations in downward shortwave flux, keeping the mean flux on a global scale nearly constant. The global mean flux difference in all skies was less than 0.01%. Statistical analyses demonstrated improved temperature and geopotential height predictions compared to reanalysis data. The anomaly correlation coefficient for East Asia at 850 hPa increased by 0.036 at 240 forecast hours. Overall, the anomaly correlation coefficient and root mean square error of geopotential height and temperature showed enhancements, particularly in the Northern Hemisphere and tropics. Importantly, the scheme introduces negligible additional memory and CPU requirements, making it suitable for both regional and global models. Only a 0.58% increase in CPU time was observed for the 10-day forecast.

The slope effects on sediment trapping process in vegetative filter strips (VFS) are usually neglected in current modelling practices for VFS operation, which hamper the VFS design and performance evaluation, especially on steep slopes. To fill the knowledge gap, 12 laboratory experiments of sediment trapping in VFS were conducted with three different inflow discharge (80, 100, and 120 ml s−1) and four slope angles (5,10, 15, and 20°). The experimental results show that, on steep slopes (10, 15, and 20°), a part of trapped sediment particles in VFS can be eroded again and then dragged to the downstream as bed load, whilst they do not move on gentle slope (5°). To describe the complex processes, a simple and effective modelling framework was developed for sloped VFS by coupling the slope infiltration, runoff, and modified sediment transport model. The model was tested against the experimental results and good agreements between the modelled and observed results were found in both runoff and sediment transport processes for all cases. On steep slopes, the sediment trapping performance of VFS decreases significantly because the erosion of deposited sediment particles can account for more than 60% of the sediment load in the outflow. The slope effect on sediment trapping efficiency of VFS varies greatly with soil, VFS, and slope properties. The model was compared with previous sediment transport equation and found that both methods can satisfactorily predict the sediment trapping of VFS on gentle slopes, but previous sediment transport equation is likely to overestimate the sediment trapping efficiency in VFS on steep slopes. This model is expected to provide a more realistic and accurate method for predicting runoff and sediment reduction in VFS on sloping surfaces. [ABSTRACT FROM AUTHOR]

• Thermokarst landslides mainly occurred before 2016 and expanded since then. • Thermokarst landslides exhibited slow creep besides seasonal deformation. • The slope effect showed serious thermokarst landslides on shady slopes. Permafrost degradation under warming climate causes a variety of topographic separation and collapses on hillslopes, collectively known as thermokarst landslides, which seriously affects the stability of the permafrost environment. However, quantitative understanding of the formation and evolution of thermokarst landslides under warming conditions is still limited, thus easily ignoring their realistic vulnerability. Here, we combined the visual interpretation of high-resolution optical satellite images, interferometric synthetic aperture radar (InSAR) measurement, and wavelet analysis to demonstrate the spatiotemporal distribution and the creep characteristics of thermokarst landslides. A total of 385 thermokarst landslides were cataloged on central Tibetan Plateau from 2010 to 2020, and most failures occurred before 2016 and then expanded. The spatial distribution of thermokarst landslides was closely related to topography. The slope effect explained a higher occurrence of thermokarst landslides on shady slopes compared to sunny ones. Time-series InSAR also documented their deformation rates from −40 to 30 mm/year, with much higher rates on shady slopes. Coupled with permafrost stratification, wavelet analysis and time-series displacement fitting traced the stratification characteristics of thermokarst landslides. The freeze–thaw cycle of the active layer results in seasonal frost heave and thaw subsidence, and when combined with the underlying permafrost degradation can form prominent thermokarst landslides. The results quantify the kinematic characteristics of thermokarst landslides and their obvious slope effects, providing a comprehensive understanding of their intrinsic development. [ABSTRACT FROM AUTHOR]

The slope aspect effect is widely distributed on the Qinghai-Tibet Plateau and has an important impact on the permafrost environment. The differences in surface heat exchange characteristics of different slope aspects in the permafrost region of Gu Mountain in the Beiluhe Basin were compared and analyzed based on observations of the south slope (sunny slope) and north slope (shadowy slope) from 2019 to 2021. The air-ground heat transfer process on the slopes was simulated using the Monin-Obukhov similarity theory. Then, the simulation results of the sensible and latent heat fluxes on the slopes were corrected and analyzed using the Bowen ratio correction method. The results show that under the influence of the solar altitude angle and subsurface conditions, the downward shortwave radiation (DR), upward shortwave radiation (UR), and upward longwave radiation (ULR) were higher on the sunny slope than those on the shadowy slope, whereas the downward longwave radiation (DLR) was lower than that on the shadowy slope. Jointly, the net radiation energy on the sunny slope was smaller than that on the shadowy slope, and the annual average net radiation difference reached 16.7 W·m−2. The annual and daily variations in soil heat flux on the sunny slope were higher than those on the shadowy slope. The energy closure rate on the sunny slope was high with a confinement rate of 0.85, whereas that on the shadowy slope was poor with a confinement rate of 0.51. The air-ground energy transfer patterns on the sunny and shadowy slopes showed obvious seasonal differences. Both slopes are dominated by the sensible heat exchange transfer mode in the cold season, whereas the shadowy slope is dominated by latent heat exchange in the warm season. This study improves our understanding of the distribution, development, and environmental effects of permafrost, under the influence of local factors.

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Inverse Distance Weighted (IDW) based interpolation method is also widely used in earth science studies. In the classical IDW method, the directional distribution of the reference points around the point to be estimated within the critical circle and the slope differences are not taken into consideration. On the other hand, in the IDW-based method developed by Shepard, the ratio of the distances of the reference points within the critical circle to the critical circle radius (r), the anisotropy and the slope differences are taken into consideration. In this study, the results of the classical IDW method and Shepard method were compared to increase the accuracy of interpolation produced from UAV data. A software has been developed to make these comparisons in more detail. The classical IDW and Shepard based interpolation methods used in this software takes into consideration the anisotropy, the slope differences and the ratio of the distances to the critical circle radius. In this study, UAV flights were performed in three different study areas with different topographic features and 3D point cloud data were obtained in order to make detailed analyzes. Using developed software, data from three different study areas have been tested and the results from different Shepard interpolation models have been discussed. The major contribution of this paper is in evaluation of various IDW options when applied to UAV point data. As a result, especially in geodetic studies form UAV data, it was observed that the results improved with 11% to 37% by using the Shepard method with the suitable power parameter value considering the directional distribution of the reference points in the critical circle and the slope differences. [ABSTRACT FROM AUTHOR]

In engineering blasting, the slope surfaces in the blasting area exert various effects on the blast vibration velocity. For example, the slope effect and the whipping effect are generated in the slope area, which will influence the blast vibration velocity. The slope area is the key protection area for many projects; therefore, it is of practical value to explore the influence of slope surface on blast vibration speed for the prediction of blast vibration and protection against it. The influence of slope effect and whipping effect on blast vibration velocity in the slope area was analyzed by numerical simulation and fitting. The field monitoring data were fitted to the blast vibration velocity prediction formula. According to the obtained fitting formula, we inferred that vibration speed amplification occurred in the slope area. Numerical simulation was carried out using the ANSYS/LS-DYNA program. Using the above two methods, whether the slope effect and whip tip effect occurred in the study area was verified. By numerical simulation, we established three-dimensional (3D) slope models for four different working conditions. We simulated the complete blasting process and the consistency between the simulation results, and the field data proved the reliability of the numerical simulation. Based on the results of the numerical simulation, we explored the variation of blasting vibration velocity under different height difference conditions. Finally, we explored the distribution law of blasting vibration at the slope surface and inside the slope. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northeast Petroleum University is the property of Journal of Northeast Petroleum University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The failure of a major flood control structure may expose the surrounding population to serious risk. Such an event kind may involve rapid transients with strong interactions between flow and topography. So, to correctly simulate the consequences of a dam failure in a complex topography, this interaction should be accounted for in mathematical modeling, which should however rely on physical descriptions that are not yet completely established. Present study explores some configurations for plane movable bed with different percent of bed slope across the dam. Experiments were carried out in an ideal flume, and instrumentation of the tests performed by means of fast digital imaging through the flume. Results show that increasing in slope lead to increasing in flow velocity and therefore increasing in eroding force and volume of transported sediment. Important result is that increasing in slope lead to nonlinear variation rate of scouring and sedimentation parameters. [ABSTRACT FROM AUTHOR]

Considering the side frictional force and the soil thrust behind pile, with nonlinear side horizontal elastic soil resistance distribution, the buckling stability analysis for tapered pile in slopes was discussed based on Rayleigh-Ritz method to obtain the formulation of critical buckling load for tapered pile in slopes. The effects of slope angle, distribution of soil thrust behind pile, pile embedded ratio, side frictional force and pile insertion ratio on buckling stability for tapered pile in slopes were analyzed. The results show that compared with equal diameter piles, the critical buckling loads for tapered piles in slopes are increased for different varying rates of pile diameter when pile tip diameter keeps constant. The critical pile buckling load is increased with the increasing of varying rate of pile diameter. Slope angle, pile embedded ratio and pile insertion ratio have significant effects on the buckling stability for tapered pile in slopes. The side frictional force is helpful to increase the critical pile buckling load, but the improvement extent is limited. The effects of the value and distribution of soil thrust behind pile on the critical pile buckling load is tiny. Both of them can be neglected. [ABSTRACT FROM AUTHOR]

In engineering blasting, the slope surfaces in the blasting area exert various effects on the blast vibration velocity. For example, the slope effect and the whipping effect are generated in the slope area, which will influence the blast vibration velocity. The slope area is the key protection area for many projects; therefore, it is of practical value to explore the influence of slope surface on blast vibration speed for the prediction of blast vibration and protection against it. The influence of slope effect and whipping effect on blast vibration velocity in the slope area was analyzed by numerical simulation and fitting. The field monitoring data were fitted to the blast vibration velocity prediction formula. According to the obtained fitting formula, we inferred that vibration speed amplification occurred in the slope area. Numerical simulation was carried out using the ANSYS/LS-DYNA program. Using the above two methods, whether the slope effect and whip tip effect occurred in the study area was verified. By numerical simulation, we established three-dimensional (3D) slope models for four different working conditions. We simulated the complete blasting process and the consistency between the simulation results, and the field data proved the reliability of the numerical simulation. Based on the results of the numerical simulation, we explored the variation of blasting vibration velocity under different height difference conditions. Finally, we explored the distribution law of blasting vibration at the slope surface and inside the slope.

The slope of ground has a significant impact on the spread and burning process for spill fires on land. In this paper, a series of continuous spill fire experiments were conducted on a fireproof glass sheet with different slope angles (0.5°, 1°, 3°) to study the effects of slope on fuel spread and burning behaviors. The results show that the spread process can be divided into four phases based on time-dependent spread area. The maximum spread area and spread rate both increased greatly with increasing slope angle for a constant discharge rate, while the effect of slope on the steady burning area was only slight. The burning rate in the quasi-steady burning phase tends to be a little lower with increasing slope. It is proved that the burning rate at the quasi-steady burning phase is lower than that of pool fires under the same burning size and the corresponding ratio is close to 0.32, independent on the discharge rate and the slope angle. Then, a simple modification coefficient was introduced and a burning rate model of spill fires was developed, which provide a basis for liquid layer simulation under the burning conditions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In actual pile engineering, the laterally loaded offshore pile built near slope is not embedded in uniform clay or sand seabed, but layered soil seabed of different types and properties. For this purpose, a method is proposed to solve the lateral characteristics of offshore pile installed near layered slope in this paper. Based on the interaction force between layered interfaces and the concept of equivalent depth, an equivalent failure wedge model is constructed to evaluate the ultimate soil resistance of each layer of soil. It is assumed that the horizontal subgrade reaction modulus of sand in each layer changes nonlinearly with depth, while the horizontal subgrade reaction modulus of clay in each layer remains unchanged. And the influence of pile diameter and slope effect on the horizontal subgrade reaction modulus is considered. The results obtained in this paper are compared with the field test results and FE results, and the accuracy of the proposed method is verified. The analysis shows that the smaller diameter has the greater impact on the lateral deflection of pile head under the same growth range of diameter. When the pile diameter changes from 1 D to 1.5 D , the lateral deflection of pile head decreases by 42%. • A method is provided to solve the lateral behavior of offshore pile installed near layered slope with different soil properties. • Based on the concept of equivalent wedge, the failure wedge model is improved and extended to the layered soil to calculate the ultimate soil resistance by considering the layered characteristics of soil, the interaction force of the layered interface and the continuity of soil reaction. • The influence of pile diameter and slope effect on the horizontal subgrade reaction modulus is considered. [ABSTRACT FROM AUTHOR]

Aerial LiDAR (Light Detection and Ranging) derived data are widely adopted for the study and characterization of forests. In particular, LiDAR derived-CHM (Canopy Height Model) has proved essential in identifying tree height variability and estimating many forest features such as biomass and wood volume. However, CHM quality may be affected by internal limits and anomalies caused by raw data (point cloud) processing (i.e., vertical errors), which are quite often disregarded by users, thus generating potentially erroneous results in their applications. In this work, an auto-consistent procedure for the fast evaluation of CHM accuracy has been developed based on the assessment of internal anomalies affecting CHM data obtained by differencing gridded DSM (Digital Surface Model) and DTM (Digital Terrain Model). To this purpose, a CHM was generated using the gridded DTMs and DSMs provided by the Cartographic Office of the Piemonte Region (north-western Italy). We estimated the local potential CHM error over the whole region, and demonstrated its strictly dependence on the terrain morphometry, particularly slope. The relationship between potential CHM error and slope was modeled separately for mountain, hill and flat terrain contexts, and used to produce a potential error map over the whole region. Our results showed that approximately 20% of the regional territory suffers from CHM uncertainty (in particular high elevation areas, including the treeline), though the majority of regional forest categories was affected by negligible CHM error. The potential consequences of CHM error in forest applications were evaluated, concluding that the tested LiDAR dataset provide a reliable basis for forest applications in most of the regional territory.

Abstract: Snow distribution modeling is important to hydrological research of alpine catchments, for the temporal and spatial evolution of snow cover has significant influence on snowmelt runoff. However, few snow distribution models have considered the slope effect on drifting snow transport. In this work, a drifting snow parameterization scheme considering the slope effect is proposed, and a snow distribution model based on snowfall and snow drifting simulations is established for alpine terrain. The validation wind‐tunnel experiments and field observations show high accuracy of our model in snow depth evaluation. Then we have analyzed the snow deposition patterns of complex terrain in detail. The results show different deposition patterns for snowfall and drifting snow, for deposition patterns for snowfall are controlled by both terrain and wind, while deposition patterns for drifting snow are mainly dominantly controlled by terrain, and the erosion or deposition rate is sensitive to the local wind speed. This work has considerable value in improving the accuracy of snow distribution prediction in alpine area, which we believe is essential for hydrological research of alpine catchments. [ABSTRACT FROM AUTHOR]

The slope effect on flow erosivity and soil erosion still remains a controversial issue. This theoretical framework explained and quantified the direct slope effect by coupling the modified Green-Ampt equation accounting for slope effect on infiltration, 1-D kinematic wave overland flow routing model, and WEPP soil erosion model. The flow velocity, runoff rate, shear stress, interrill, and rill erosion were calculated on 0°-60° isotropic slopes with equal horizontal projective length. The results show that, for short-duration rainfall events, the flow erosivity and erosion amounts exhibit a bell-shaped trend which first increase with slope gradient, and then decrease after a critical slope angle. The critical slope angles increase significantly or even vanish with increasing rainfall duration but are nearly independent of the slope projective length. The soil critical shear stress, rainfall intensity, and temporal patterns have great influences on the slope effect trend, while the other soil erosion parameters, soil type, hydraulic conductivity, and antecedent soil moisture have minor impacts. Neglecting the slope effect on infiltration would generate smaller erosion and reduce critical slope angles. The relative slope effect on soil erosion in physically based model WEPP was compared to those in the empirical models USLE and RUSLE. The trends of relative slope effect were found quite different, but the difference may diminish with increasing rainfall duration. Finally, relatively smaller critical slope angles could be obtained with the equal slope length and the range of variation provides a possible explanation for the different critical slope angles reported in previous studies. [ABSTRACT FROM AUTHOR]

A comprehensive numerical study is performed to reveal influence of the upstream wall slope on aerodynamic properties as rarefied hypersonic flows pass through the two- and three-dimensional cavity configurations using the direct simulation Monte Carlo (DSMC) method. In this work, slope effect is obtained by the cavity upstream wall sloping upward and downward as well as bulging partially. Besides, cases of freestream with different velocities and altitudes are taken into account to examine the slope effect. It is found that cavity flow is transformed from the open type to the transitional and finally to the closed as the cavity upstream wall gradually slopes upward, promoting the heat energy exchange between gas molecules with the cavity floor, and meanwhile achieving a considerable rate of decrease of the peak heat flux on the reattachment corner. However, the upstream wall sloping downward or bulging partially seems to only have a slight effect on cavity flow and wall heat flux. It's worth noting that slope effect is closely related to velocity and altitude of the freestream, such as the greater the velocity and altitude, the stronger the slope effect. For the three-dimensional cavity configuration, influence of the upstream wall slope on cavity flow and wall heat flux is weaken considerably due to the three-dimensional effect. From the perspective of optimal design for the hypersonic thermal protection system, the cavity with an upward upstream wall is proposed because it not only reduces peak heat flux on the reattachment corner, but also decreases gas temperature inside the cavity. [ABSTRACT FROM AUTHOR]

Aerial LiDAR (Light Detection and Ranging) derived data are widely adopted for the study and characterization of forests. In particular, LiDAR derived-CHM (Canopy Height Model) has proved essential in identifying tree height variability and estimating many forest features such as biomass and wood volume. However, CHM quality may be affected by internal limits and anomalies caused by raw data (point cloud) processing (i.e., vertical errors), which are quite often disregarded by users, thus generating potentially erroneous results in their applications. In this work, an auto-consistent procedure for the fast evaluation of CHM accuracy has been developed based on the assessment of internal anomalies affecting CHM data obtained by differencing gridded DSM (Digital Surface Model) and DTM (Digital Terrain Model). To this purpose, a CHM was generated using the gridded DTMs and DSMs provided by the Cartographic Office of the Piemonte Region (north-western Italy). We estimated the local potential CHM error over the whole region, and demonstrated its strictly dependence on the terrain morphometry, particularly slope. The relationship between potential CHM error and slope was modeled separately for mountain, hill and flat terrain contexts, and used to produce a potential error map over the whole region. Our results showed that approximately 20% of the regional territory suffers from CHM uncertainty (in particular high elevation areas, including the treeline), though the majority of regional forest categories was affected by negligible CHM error. The potential consequences of CHM error in forest applications were evaluated, concluding that the tested LiDAR dataset provide a reliable basis for forest applications in most of the regional territory. [ABSTRACT FROM AUTHOR]

Deforestation and natural grassland conversion to agricultural land use constitute a major threat to soil and water conservation. This study aimed at assessing the status of land cover and land use (LCLU) in the Lake Kivu basin, and its related impacts in terms of soil erosion by water using the Universal Soil Erosion Equation (USLE) model. The results indicated that the Lake Kivu basin is exposed to soil erosion risk with a mean annual rate of 30 t·ha-1, and only 33% of the total non-water area is associated with a tolerable soil loss (⩽10 t·ha-1). Due to both natural factors (abundant tropical precipitation and steep slopes) and anthropogenic activities without prior appropriate conservation practices, all land-use types-namely settlement, cropland, forestland, and grassland-are exposed to a severe mean erosion rate of 41 t·ha-1, 31 t·ha-1, 28 t·ha-1, and 20 t·ha-1, respectively. The cropland that occupied 74% of the non-water area in 2015 was the major contributor (75%) to the total annual soil loss in the Lake Kivu basin. This study showed that conservation practices in the cropland cells would result in a mean erosion rate of 7 t·ha-1, 18 t·ha-1, and 35 t·ha-1 for terracing, strip-cropping, and contouring, respectively. The adoption of terracing would be the best conservation practice, among others, that could reduce soil erosion in cropland areas up to about 23%. The erosion risk minimization in forests and grasslands implies an increase in overstorey canopy and understorey vegetation, and control of human activities such as fires, mining, soil compaction from domestic animals grazing, and so on. Soil erosion control in settled areas suggests, among other things, the revegetation of construction sites, establishment of outlet channels, rainfall water harvesting systems, and pervious paving block with grass. [ABSTRACT FROM AUTHOR]

Environmental tracers of atmospheric origin are widely used to localise geographically recharge to aquifers and to quantify its average value. The most commonly used atmospheric tracers are chloride, water stable isotopes, tritium and radiocarbon. Their average input is spatially variable. Spring and pumped groundwater samples are often mixtures of water from a range of depths and thus their concentration in water may conspicuously differ from the tracer content in local recharge and even the recharge produced at the centroid of some up flow area. In the case of radiocarbon, most interpretation efforts are devoted to know the part of dissolved inorganic carbon originated from biogenic soil CO 2 but seldom is considered that the water sample is often a mixture corresponding to a wide range of flow times along different paths in the unsaturated and saturated zones. Environmental tracer content in groundwater samples from large springs and long–screened pumped wells is interpreted and quantified. This is done under simplified idealised conditions, in homogeneous formations and under steady–state flow and mass transport through the unsaturated and saturated zones. Different input forms of the environmental tracer flow and mixing are considered, according with their specific characteristics, assuming linear variations with distance over the territory and three basic geometrical settings: parallel flow, radial divergent flow and radial convergent flow, besides a two-level geometry with homogeneous inputs. Tracer content in samples similar to those from a well-mixed reservoir differs from that of local recharge and depends on geographical position. The quantitative understanding of the slope effect, even if deduced from synthetic cases, improves recharge evaluation by means of chloride, shows how consider water isotopic distribution and altitudinal gradient in the aquifer, and demonstrates that radiocarbon ages may depend on position for a given geometrical shape of the aquifer, besides the large influence of the unsaturated zone thickness. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The nonlinear response of horizontally loaded piles located at the crest of offshore cohesionless soil slope is analyzed, based on the failure wedge model (FW) with variational base angle, in this study. The pile deflection differential equation considering the three-dimensional friction effect is derived; the failure wedge model with the variational base angle on slope crest is proposed; the three-dimensional friction effect along the pile on the failure wedge is considered; the calculation formula for ultimate soil resistance around pile on cohesionless soil slope crest is derived. The feasibility of the proposed method is proved by comparing the theoretical results with the test results. Finally, the slope effect and friction effect along the pile on laterally loaded pile behavior and the influence of pile diameter on the friction effect are analyzed and discussed based on the proposed method. Slope can weaken the soil resistance around the pile, while friction can strengthen that around the pile. The friction effect gets more significant with the increase of pile diameter. • The pile deflection differential equation considering three-dimensional friction effect is derived; the failure wedge model with variational base angle on slope crest is proposed; the three-dimensional friction effect along the pile on the failure wedge is considered. • The nonlinear response of horizontally loaded piles located at the crest of offshore cohesionless soil slope is analyzed with the proposed method. • The slope effect and friction effect along the pile on laterally loaded pile behavior and the influence of pile diameter on the friction effect are analyzed. [ABSTRACT FROM AUTHOR]

• Laboratory rainfall-runoff experiments with adjustable soil slope are presented. • Two adjacent soils are used to generate the run-on process. • Run-on modulates the slope effects on deep flow and surface runoff. • Capillarity and gravity produce different variation of infiltration with slope angle. The influence of soil surface gradient on rainfall infiltration and related surface runoff generation are not well understood for representation in hydrologic modeling because of conflicting theoretical formulations and experimental results available in the scientific literature. The main objective of this study is to integrate and extend previous laboratory experiments using artificial rainfall over a laboratory setup with adjustable slope angle (α) and consisting of two adjacent natural bare soils that according to the USDA soil classification were of loam (Soil 1) and sandy loam (Soil 2) type, respectively. Soil 2, placed downstream, was subjected to the run-on process due to the overland flow produced over Soil 1. The slope effects are discussed on the basis of measurements of runoff surface (Q S) and deep flow (Q d), both strictly linked to the infiltration rate, supported by a simplified rainfall-runoff model. Our results indicate that at a time close to the end of rainfall period (t re =8 h), for α increasing from 1° to 10°, Q d decreased by about 25% while Q S exhibited a corresponding increase in magnitude. In the same slope range, at t → t re the total volume of water collected as deep flow decreased by about 40% for heavy rainfall and up to about 50% for light rainfall. On the other hand, a growth of the total surface water volume occurred such that the total outflow volume was nearly independent of α. The run-on effect is seen to modulate the differences in steady deep flows for different slopes. The above variations became of minor interest between 10° and 15°. The significant differences in the variations of surface and deep flow to changes of slope angle were analyzed and placed in context with those from earlier experiments. The differences are attributed to a different level of interaction between capillary and gravitational effects that should be represented in existing infiltration models, because appreciable values of α characterize most watershed areas and the decrease of infiltration with increasing α over bare soils can imply a greater contribution to the direct runoff and a significant reduction of the groundwater recharge with respect to a flat surface. [ABSTRACT FROM AUTHOR]

In steep channels, debris flows are known to dramatically increase in volume under the effect of channel erosion. However, the critical factors controlling channel erosion by debris flows are not well documented by field studies. This is particularly true for the effect of slope on the depth at which erodible beds are scoured during debris flows and during bedload transport. This topic has been addressed by intensive cross section resurveys (54 cross sections) of debris flows (n = 5) and flow events (n = 9) that occurred in two torrents of the French Prealps, the Manival and Réal torrents, between 2009 and 2012. This study provided evidence that debris-flow scouring increases with slope, whereas this is not the case for bedload transport (no slope effect detected during floods). A functional relationship defined from a piecewise regression model is proposed as an empirical fit for the prediction of channel erosion by debris flows with a critical slope threshold at 0.19 (95% confidence interval: 0.17–0.21). This slope threshold is interpreted as the transition between the transport-limited and supply-limited regimes, associated with the upstream decreasing erodible bed thickness. The erodible bed was also characterized by quantifying erosion, deposition, and surface roughness with multidate terrestrial laser scans (TLSs) in a short reach of high sensitivity of the Manival torrent. Debris-flow erosion occurred preferentially on smooth surfaces corresponding to the unconsolidated gravel deposits from bedload transport. A 20-cm resolution roughness profile from an airborne laser scan (ALS) and a slope profile of the whole channel were used to detect the unconsolidated sediment deposits that can potentially feed future debris flows. [ABSTRACT FROM AUTHOR]

This paper develops a method for calculating nonlinear lateral response of offshore rigid monopile in sand under slope effect. The method modifies three-dimensional wedge failure model to evaluate the ultimate soil resistance in front of the laterally loaded rigid monopile near sloped ground. The modified model considers the ultimate horizontal frictional resistance, the slope effect, the vertical friction force, the mutual influence of the forces within the wedge. And the base horizontal shear resistance is considered in the method. In addition, the load-displacement curves of the rigid monopile under five different distribution modes of the soil reaction along the pile are calculated by the force and moment equilibrium equations. The method in this paper is verified by comparing its results with those of field test, 3D FE model, 1g laboratory model test and existing analytical methods. Finally, this method is used to study the rotation behavior and lateral response of the offshore rigid monopile. • This paper considers different wedge failure models to evaluate the ultimate soil resistance in front of the monopile (p u f ) located near slope in sand. • The improved wedge failure model account for the ultimate horizontal frictional resistance, the vertical friction force, the slope effect and the mutual influence of the forces within the wedge. • A method for calculating the response of laterally loaded rigid monopile under slope effect is proposed, which can account for different levels of lateral response of offshore monopile. • The base horizontal shear resistance of pile bottom and its bending moment are also considered. [ABSTRACT FROM AUTHOR]

Abstract: This study examines catchment basin analysis of stream sediment samples considering slope effect by incorporating 3D surfaces of catchments and lithologic units within the Rudbar 1:100,000 scale geological map (1:50,000 scale Mahin topographic sheet) in Northern Iran. In this region, 174 stream sediment samples were collected in 625km2 of survey area and were analyzed by ICP-OES for trace elements. Background values due to upstream lithologic and dilution effects were calculated using 2D and 3D modeling. In each case, background concentration for every element due to lithology was estimated by weighted average method, and then geochemical residuals were determined and used for dilution effect correction. To identify the areas with possible mineralization, dilution-corrected values in both 2D and 3D models were processed further separately using principal component analysis. Then appropriate principal components (PCs) were integrated by fuzzy OR operator to obtain a mineral favorability map per model. Rock samples, collected over the area, were used to validate the results. Both 2D and 3D models have good agreement with the validation samples, but the 3D model was better. In other words, the use of 3D surfaces allows better representation of anomalies in the study regions. In addition, validation against rock sample analyses demonstrated that using 3D surfaces improves the delineation of promising catchment basins. The effectiveness of incorporating slope effect in catchment basin modeling of promising areas was observed in dilution correction of background and in multivariate analysis of dilution-corrected residuals. Non-parametric significance test also confirmed that results using 2D and 3D surfaces are different. [Copyright &y& Elsevier]

An extensive program of laboratory model tests was undertaken to study the effect of slope and loading direction on laterally loaded piles in cohesionless soil. The paper includes studies of the effect of distance from the crest of the slope (both slope side and embankment side), soil properties, and loading direction (both forward in the direction of the slope and reverse loading). The pile lateral capacity in sloping ground was compared with that in horizontal ground. From the experimental investigation, it is observed that when piles installed in sloping ground undergo forward loading, lateral capacities of the piles are almost reached at 8% of the pile diameter in loose-to-medium dense soil and 16% of the pile diameter in dense soil. If the pile is placed times the pile diameter away from the slope crest within the embankment, the influence of slope in the lateral-load capacity is almost negligible under both forward and reverse lateral load. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the effectiveness of liquefaction countermeasures for residential houses was explored using a fully coupled dynamic effective-stress finite element procedure. Numerical analyses were conducted on two wooden houses that were damaged to different degrees due to dune liquefaction during the 2007 Niigata Chuetsu-offshore earthquake. House A, which was only improved by horizontal drainage pipes to lower the ground water level, was completely destroyed; however, house B, which was improved by a horizontal drainage system, soil–cement mixtures, and steel-pipe piles, was slightly deformed. Numerical results show that the effects of the sand dune slope on the damage to the two houses were somewhat different. For house B, it was found that the steel-pipe piles were more effective. Two countermeasures generally led to a greater degree of reduction in both lateral and vertical displacements of house B than only a single countermeasure employed. In addition, the combined implementation of steel-pipe piles and soil–cement mixtures was the most effective among the cases with two countermeasures. [Copyright &y& Elsevier]

Abstract: We derive the motion energy dissipation model to investigate the relation between the additional energy loss of vehicles and the slope of a gradient. Simulations are carried out to check the validity of the dissipation model. Analysis of the results shows that the total energy consumption is inversely proportional to the slope in an uphill situation and the opposite conclusion can be drawn in a downhill situation. The energy dissipation rate depends on the density of traffic and the road length in two situations in a rule. It is found that the simulation result is in good agreement with real traffic. [Copyright &y& Elsevier]

Drainage ditches play an important role in maintenance of plant species diversity. We investigated plant species composition and diversity, and soil and water chemical properties in drainage ditches in the Hetao Irrigation Region of northern China. We compared species composition similarity within the same and among different drainage areas, and compared diversity of plant species, among different ditch sizes and slope positions. We identified a total of 70 plant species, which belonged to 64 genera and 30 families in the drainage ditch. The most frequent family was Compositae representing 15.7% of the total flora;Phragmites australis(Cav.) Trin. ex Steud was the most widespread species with a frequency of more than 60% in all plots. The highest similarity values occurred in lateral ditches within the same drainage areas, and in main ditches among different drainage areas. The coefficient of variation of total salt in soil was closely related to species similarity in all ditches. Ditch size and position were significantly correlated with the indexes of species diversity. Higher plant α-diversity occurred in smaller ditches and tended to be the highest at the transition zone and on the slope of the ditches. The response of species composition and diversity to environmental factors was significant for saline concentrations. Reducing the current water and soil saline contents, while maintaining current slope soil nitrogen content was suggested as an optimal way of maintaining high species diversity. [ABSTRACT FROM AUTHOR]

Abstract: A series of nine fire experiments was conducted on a large-scale bench with an inclinable plate to study the effects of a slope on fire spread. The temperature and total and radiant heat flux densities were measured at the top of the fuel bed during the upslope fire spread in still air. Measurements were recorded at five different locations ahead of the fire front. The effects of the slope on the flame topology, fire dynamics, and heat transfers ahead of the fire front were observed. The thermal measurements and image analyses showed a change in the fire spread regime and its related behavior with an increase in the slope. This was observed through an elongation of the flame and its contact surface over the upper part of the fuel bed. When the slope increased, the fire topology changed from a U-shape to a V-shape, and the radiation-dominated thermal environment ahead of the flame front was progressively turned into a mixed convective-radiative one, in which convection finally dominated for steep slope configurations. For fire spreading across a 30° slope, this increase in the curvature of the fire front (V-shape) is associated with the appearance of fire whirls rolling along the flanks of the fire front, which indicates significant changes in the fluid mechanics and heat transfers. The span of the heat transfer increased and a significant amount of energy impinged 1 or 2m ahead of the flame front because of the flame tilt (radiation) and hot gas flow (convection). The measurements also indicated a greater amount of energy impinging in the center of the fuel bed than at the edge. This study shows the importance of investigating the fluid mechanics of fire in future wildfire researches. [Copyright &y& Elsevier]

Abstract: Repetitive auditory stimulation (with click trains) and visual velocity signals both have intriguing effects on the subjective passage of time. Previous studies have established that prior presentation of auditory clicks increases the subjective duration of subsequent sensory input, and that faster moving stimuli are also judged to have been presented for longer (the time dilation effect). However, the effect of clicks on velocity estimation is unknown, and the nature of the time dilation effect remains ambiguous. Here were present a series of five experiments to explore these phenomena in more detail. Participants viewed a rightward moving grating which traveled at velocities ranging from 5 to 15°/s and which lasted for durations of 500 to 1500ms. Gratings were preceded by clicks, silence or white noise. It was found that both clicks and higher velocities increased subjective duration. It was also found that the time dilation effect was a constant proportion of stimulus duration. This implies that faster velocity increases the rate of the pacemaker component of the internal clock. Conversely, clicks increased subjective velocity, but the magnitude of this effect was not proportional to actual velocity. Through considerations of these results, we conclude that clicks independently affect velocity and duration representations. [Copyright &y& Elsevier]

A novel lattice traffic flow model with a slope effect is proposed. Neutral stability condition is obtained by the use of the linear stability theory. The standard KdV equation is derived in the meta-stable region and soliton solution is obtained near the neutral stability line. The solitary waves are reproduced through the numerical simulations. Results show that the solitary density wave appears in upward form when the average density is less than critical density, otherwise it exhibits downward form. [ABSTRACT FROM AUTHOR]

Summary: Climate change is expected to have a profound influence on soil moisture. According to that the present study aimed at the investigation of future soil water evolution by considering the relationship between soil moisture changes resulting from climate change projections, soil, and terrain characteristics, with special emphasis on slope and groundwater depth. The distributed hydrological model WaSiM-ETH was used to simulate root zone soil water content at a 1km grid resolution in the 1700km2 Thur river basin (NE Switzerland) during the 6-month period from April to September. The model was driven by baseline climate data from national data records for 1981–2000, or by scenario data for 2081–2100. The latter were based on grid point projections of two global climate models (CSIRO [B2] and HadCM3 [A2]). The datasets were completed with observations and simulations for the exceptionally warm and dry summer of 2003. The results suggested that a warmer climate with less summertime precipitation may significantly lower the seasonal mean soil water content in many parts of this basin, leading to frequent water stress conditions. Strongest effects occurred with HadCM3, and to a similar extent with 2003 weather data. The magnitude of soil moisture changes were related to land use, soil texture, and slope. In relative terms, reductions in soil water were largest for sloping soils with low water storage capacity, and also larger for forests than for cropland and grasslands. In absolute (volumetric) units, most pronounced reductions were indicated for flat areas with good water supply (mostly dominated by cropland). Here, the rooting zone was often connected to the groundwater, and capillary rise counteracted soil water depletion under current climate during the first half of the season, but was disconnected much earlier under climate change conditions. In steeper areas, groundwater had no influence and thus soil water content changed mainly in response to decreased precipitation and increased evapotranspiration. It is concluded that soil water contents generally decline in this pre-alpine river basin with climate change, but that the degree of soil water depletion varies with climate scenario, land use, soil texture, and topographic conditions. Thus, realistic soil water projections require reliable predictions of summertime climate, and the use of a full representation of biophysical processes that control evapotranspiration, including vertical and lateral subsurface water flows. [Copyright &y& Elsevier]

An asymmetric failure mode of soil in front of laterally loaded piles at the slope crest is presented to estimate the pile bearing capacity in this study. The effect of soil shear strength below the rotation center is taken into account by postulating the suppositional sliding curve and corresponding mobilization coefficient of soil strength. Subsequently, the soil resistances above the rotation center at soil failure can be obtained by upper bound theorem of limit analysis. Employing static equilibrium equations, the analytical solution of lateral bearing capacity of piles is assessed by adopting the concept of effective embedment depth. The analytical solution, considering the the slope effect on limiting force profile, is then validated by numerical predictions and full-scale tests. Furthermore, a non-dimensional coefficient, capacity ratio, is proposed to characterize the slope effect on the bearing capacity of laterally loaded piles, and the range of capacity ratio for different internal friction angles are differentiated as different distribution areas. The effect of distance between the pile and slope crest on pile bearing capacity is further investigated, and the capacity ratios appear to be approximatively linear with normalized distance λ and would increase to 1 until λ exceeds the critical value. [ABSTRACT FROM AUTHOR]