Ground Slope Research Articles

Simulation Study on Risk and Influencing Factors of Cadmium Loss in Contaminated Soil

Cadmium (Cd) in contaminated soil not only enters surface water via rainfall runoff but also penetrates groundwater, adversely affecting human health through the food chain. This research examined three kinds of soil from Luoping County in southwestern China, with different Cd pollution levels. Simulated rainfall and soil column leaching experiments were conducted to explore the risks and factors influencing Cd loss in surface runoff and underground leaching water at different ground slopes (6°, 12°, 18°, and 24°), rainfall intensities (30, 60, and 90 mm∙h−1), and soil profile conditions. The results show that the risk of soil Cd runoff loss increased at a higher rainfall intensity or Cd pollution degree, reaching a peak at a ground slope of 18°. The main factor affecting soil Cd runoff loss was rainfall intensity followed by Cd soil pollution degree and slope. The risk of soil Cd leaching loss was mainly determined by the leaching time and soil depth. The primary factor affecting soil Cd leaching loss was leaching time, followed by soil depth. The soil organic matter (SOM) concentration and pH minimally affected soil Cd loss. The research results provide a theoretical basis for risk management and control of cadmium loss in contaminated soil, and indicate that the environment-friendly water treatment method of high concentration Cd polluted runoff deserves attention.

COMPARATIVE STUDY OF A TALL BUILDING WITH CONVENTIONAL AND FLAT SLAB SITUATED ON SLOPING GROUND UNDER SEISMIC FORCES

The structures are generally constructed on plain surface, but due to scarcity of plain ground in hilly regions leads to construction of building on a sloping ground. One of the biggest challenges of structural engineer is to design an earthquake resistant building on sloping ground. In present study conventional slab & flat slabs with RC building situated on sloping ground without any change of natural terrain have been considered for the analysis. The modeling & analysis of RC building has been done by using structure analysis tool ETABS 2019, to study the behavior of building for earthquake force. The equivalent static analysis and response spectrum analysis apply on building results were obtained in the form of maximum displacement, story drift, story shear, base shear, time period, axial force, shear force, bending moment.

Effects of Ground Slopes on Erector Spinae Muscle Activities and Characteristics of Golf Swing.

(1) Background: 'Slope' refers to the position faced by golfers on the course. Research on the recruitment strategies of thoracolumbar erector spinae during golf swings on different slopes may help us to understand some underlying mechanisms of lower back pain. (2) Purpose: The purpose of the present study is to assess electromyography (EMG) patterns of the erector spinae muscles (ES) and the kinematics of the trunk and swing parameters while performing golf swings on three different ground slopes: (1) no slope where the ball is level with the feet (BLF), (2) a slope where the ball is above the feet (BAF), and (3) a slope where the ball is below the feet (BBF). Furthermore, the present study evaluates the effect of slope on the kinematics of the trunk, the X-factor angle, and the hitting parameters. (3) Methods: Eight right-handed recreational male golfers completed five swings using a seven-iron for each ground slope. Surface electromyograms from the left and right sides of the ES thoracolumbar region (T8 and L3 on the spinous process side) were evaluated. Each golf swing was divided into five phases. Kinematics of the shoulder, trunk, and spine were evaluated, and the ball speed, swing speed, carry, smash factor, launch angle, and apex were measured using Caddie SC300. (3) Results: The muscle activity of the BAF and BBF slopes was significantly lower than that of the BLF slope during the early follow-through phase of the thoracic ES on the lead side (i.e., left side) and during the acceleration and early follow-through phases of the lumbar ES on the lead side. The lead and trail side (i.e., right side) lumbar ES were more active during acceleration than the thoracic ES. Additionally, the trends of the lead and trail sides of the thoracolumbar regions on the three slopes were found to be the same across the five phases. Trunk angle and X-factor angles had no significant differences in address, top of backswing, or ball impact. The maximum separation angles of the X-factor appeared in the early phase of the downswing for all the three slopes. Regarding smash factor and launch angle, there were no significant differences between the three slopes. The ball speed, swing speed, carry, and apex were higher on BLF than on BAF and BBF slopes. (4) Conclusion: The findings suggest that amateur golfers face different slopes with altered muscle recruitment strategies. Specifically, during the acceleration phase of the golf swing, the BAF and the BBF slopes, compared with the BLF slope, significantly underactivated the lead side thoracolumbar erector spinae muscles, thereby increasing the risk of back injury. Changes in muscle activity during critical periods may affect neuromuscular deficits in high-handicap players and may have implications for the understanding and development of golf-related lower back pain. In addition, the X-factor angle was not affected by the slope, however, it can be found that the hitting parameters on the BLF slope are more dominant than on the other slopes.

Seismic Response of Braced RCC Building with Variable Ground Slopes

Seismic Response of Braced RCC Building with Variable Ground Slopes

Static and dynamic story shear in split-level building on sloping ground

Building structures located on slopes behave differently than structures located on flat ground because of the different levels of stepped floors made to overcome the slope of the land, resulting in several layers of basements. Also, due to the existence of these steps and the difference in soil level, a retaining wall is often made to hold the soil. The forces acting on the structure consist of those acting on the structure and those acting on the retaining walls, both against gravity loads and against earthquake loads. Often, there is an avalanche force due to the stability of the slopes. The main objective of this research is to: evaluate the distribution of story-shear forces based on a static and dynamic analysis of building structures. This paper discusses the structure of a seven-story building with stepped floors, which is then used to calculate a similar structure with 14 levels. In this case study, the load due to lateral earth pressure is calculated separately from the building structure with the assumption that the retaining wall (soldier-pile) can carry the lateral earth pressure as well as overcome sliding due to slope stability. Therefore, the building structure can be designed separately without considering the presence of lateral forces due to differences in soil levels. In conclusion, the results of the static and dynamic analysis showed the distribution of the story-shear forces from the first to seventh floors as smaller than those of the eighth floor.

Seismic analysis of Multi storey Building on Sloping Ground and Flat Ground by using ETABS

Due to urbanization and industrialization, which paved the door for the development of tall, multi-story structures on mountainous terrain, land is scarce in emerging nations like India. Buildings built on hilly terrain differ from those built on flat terrain due of their uneven and asymmetrical vertical and horizontal structures. These buildings are also significantly more vulnerable to earthquake pressures when located in mountainous terrain. The primary goal of the current endeavor is to investigate how structures behave on level and sloping terrain. Hilly places require different construction configurations than level areas. Hill structures vary from those on lowlands in that they are torsionally linked, highly irregular, and asymmetrical in both the horizontal and vertical planes. As a result, they are vulnerable to severe damage when an earthquake strikes. The behavior of a multi-story structure with two distinct slope angles was attempted to be studied in this paper, and a comparison with flat ground was made. by taking Earthquake Zone II into account. Buildings on level ground and buildings on slanted ground are compared. The models are created with the aid of the structural analysis program ETABS. Response spectrum analysis is used for analysis. The analysis’s findings, including storey shear, storey drifts, moments, and displacement, are tabulated and examined.

Tractor Rollover Accidents: A Review of Factors and Safety Measures

This paper focuses on tractor rollovers because they account for more than half of all the tractor-related deaths. As per international Labour organization more than 1247 deaths happen annually and more than 60,000 people get seriously injured due to tractor rollover. In addition, farm tractor operational safety principles are also highlighted. It has been observed through this study that the tractor rollovers occur when a tractor tips over, potentially crushing the operator. Furthermore, rollovers can happen on any terrain, but they are more likely to occur on sloping ground or when making sharp turns at high speed. Other factors that can contribute to rollovers include hitting obstacles, improper use of implements, and not using a rollover protective structure (ROPS) or seat belt.

Analysis of Tread ICRs for Wheeled Skid-Steer Vehicles on Inclined Terrain

The instantaneous centers of rotation (ICRs) for the two treads of skid-steer vehicles moving with low inertia on hard horizontal terrain almost remain with constant local coordinates, which allows to establish an equivalence with differential-drive locomotion. However, this significant kinematic relationship has not been analyzed yet on sloped ground. One relevant difficulty of studying ICR behavior on inclined terrain, even on a flat surface, is the continuous variation of pitch and roll angles while turning. To overcome this problem, this paper analyzes a dynamic simulation of a skid-steer vehicle on horizontal ground where gravity is substituted by an equivalent external force in such a way that pitch and roll are kept constant. Relevant tread ICR variations on inclined ground have been deduced, which have a significant impact on skid-steer kinematics. These new findings have been corroborated experimentally with a four-wheeled mobile robot that turns on an inclined plane.

Estimating Mediterranean stand fuel characteristics using handheld mobile laser scanning technology

Background Accurate, timely and easily obtainable information on stand fuel is of great importance in the prediction of fire behaviour. Aims The objective of this study is to measure several stand fuel characteristics with handheld mobile laser scanning (HMLS) in six fuel types for Mediterranean region, and compare the results with traditional field fuel measurements (FFM) in 35 different sampling plots. Methods The measurements involved overstorey (the number of trees, diameter at breast height, crown base height, tree height, maximum tree height, stand crown closure) and understorey (understorey closure, understorey height) fuel characteristics, and ground slope. Correlation analysis and t-test were performed to examine the relationship between FFM and HMLS datasets. In addition, cross-validation statistics (RMSE, rRMSE and R2) were employed to evaluate the accuracy of the HMLS method. Key results The results indicated strong correlations among all fuel characteristics. However, overstorey fuel characteristics were more favourable (r-values between 0.804 and 0.996, P < 0.01) than understorey (r-values between 0.483 and 0.612, P < 0.01). There was no significant difference between FFM and HMLS datasets in all fuel characteristics (P > 0.05). Conclusions The results indicated that the HMLS was practical, cost-effective, time-efficient and required less labour as compared to traditional FFM in plot-level (i.e. 0.1 ha) inventories.

Application of bivariate approaches for flood susceptibility mapping: a district level study in Eastern India

The main objective of this present study is to prepare flood susceptibility mapping using bivariate approaches considering parameters such as rainfall, geomorphology, geology, soil, elevation, ground slope, curvature of the land, flow directions, stream density, distance from road, distance from river, land use land cover, topographic wetness index, normalized differentiate vegetation index and water index. Bivariate methods like Shannon's Entropy Index (SEI) and Weight of Evidence (WofE-IV) models have been used in conjunction with remote sensing and geographical information system and it was found that 17.77% (SEI) and 11.20% (WofE-IV) area of the district categorized as highly susceptible to flood especially found in the adjoining area of Tangon, Punarbhaba, and Atreyee rivers. Around 26–35% of the total area is safe from flood especially located in the Tapan and Banshihari block. The area under curve values (SEI = 0.954, WofE-IV = 0.913) shows that both models are performing well for flood susceptibility mapping.

Effect of grain dissolution on sloping ground

The static and dynamic stability of natural or constructed slopes can be affected by dissolution or dissolution-like phenomena. Their underlying mechanisms, however, remain unclear. New experimental results and discrete element simulations provide particle-level and macroscale information on the consequences of mineral dissolution on slope behavior. At the microscale, load-carrying grain arches develop around dissolving particles, the porosity increases, and contact force chains evolve to form a honeycomb topology. At the macroscale, while vertical settlements are the prevailing deformation pattern, lateral granular movements that create mass wasting are prominent in sloping ground, even under the quasi-static granular loss. Horizontal grain displacement is maximum at the surface and decreases linearly with the distance from the slope surface to become zero at the bottom boundaries, much like vertical granular displacement along the depth. Sediments with smaller friction angles and steeper slopes experience greater displacement, both vertically and horizontally. Slopes become flatter after dissolution, with the reduction in slope angle directly related to the loss in ground elevation, ΔH/Ho. Yet, because of the porous fabric that results from dissolution, vertical shortening is less than the upper bound, estimated from the loss in the solid mass fraction, ΔH/Ho≈SF. Under water-saturated conditions, the post-dissolution fabric may lead to sudden undrained shear and slope slide.

Slope characteristics of urban construction land and its correlation with ground slope in China

Abstract Since the 21st century, China’s urban construction land has been growing rapidly, piquing academic interest. However, mountainous counties account for the majority in China, previous studies have concentrated on the horizontal expansion characteristics of construction land, leaving a gap in the vertical expansion. This study used datasets for urban construction land and digital elevation model to analyze the spatiotemporal evolution characteristics of construction land slope in 2670 China’s counties, by exploratory spatial data analysis. Furtherly, we explored the slope relationship between ground and construction land using regression analysis. The findings indicate what follows: (1) The average slope of construction land had a spatial pattern of “high in the south and low in the north,” with significant spatial agglomeration characteristics. And it had increased with the urban expansion, shifting the slope-weighted mean center toward the southeast while enhancing spatial agglomeration. (2) There was a significant and steadily rising linear association between the urban construction land slope and ground slope, due to spatial heterogeneity; the most affected counties were primarily located near the Sichuan basin. According to the results, we provided suggestions for the rational use and sustainable development of land in cities, especially for mountainous regions in a period of rapid urbanization.

Useful indicators and models for assessing erosion control ecosystem service in a semi-arid forest landscape.

Forests provide a large array of ecosystem services (ESs) such as wood supply, extreme natural event prevention, and ecotourism opportunities. The quantitative characterization of ESs is a crucial but costly task for environmental managers. The aim of this study was to develop easily applicable models and indicators for assessing erosion control ES in a semi-arid landscape. In order to accomplish this, 107 randomly selected plots were visited for field measurements and topsoil sampling. Several parametric tests were then used to analyze the field data. The findings revealed that (i) normalized difference vegetation index (NDVI), (ii) cover management (C) factor of the Revised Universal Soil Loss Equation (RUSLE), (iii) soil organic matter content, (iv) canopy cover ratio, and (v) land use/land cover (LULC) types could be used as useful performance indicators of erosion control ES. Two regression models were developed based on these indicators and compared to RUSLE results for the study area. Using the first model, we were able to estimate the soil protection performance of different LULC types by NDVI at the pixel level (R2adj = 0.90, p < 0.05). The second model estimated annual potential soil loss using NDVI and ground slope values (R2adj = 0.57, p < 0.05). Based on the ES indicators framework, a practical approach was proposed in this study for rapid assessment of the soil erosion problem without running RUSLE. Thus, environmental managers are expected to make well-informed landscape planning decisions and improve their ES provision application capabilities at a reduced cost.

Simulation Study for Overturning and Rollover Characteristics of a Tractor with an Implement on a Hard Surface

The effects of the slope of the ground and the obstacle conditions on the lateral overturning/backward rollover of a tractor with an implement were analyzed through dynamic simulation. The tractor and implement’s 3D simulation model was constructed. As for simulation conditions, four heights and three shapes were set for obstacles, and eight slopes were set for the ground to be traveled by the implemented tractor. Under each condition, the critical speed at which the tractor begins to overturn and roll over was derived, and factors that caused the overturn and rollover were analyzed. As a result of instability types, backward rollover happens when the ground slope is low and lateral overturning happens at a specific slope or higher regardless of the obstacle conditions. In the case of the tractor and implement under study, the tendency changed at a slope of 25°. As the obstacle height increased, overturning and rollover safety decreased. In the case of the obstacle shape, safety was lowest for the rectangular obstacle and highest for the right-side triangular obstacle. The driving safety of the tractor with the implement was lower than that of the tractor with no implement. This appears to be mainly due to the change in the position of the center of gravity caused by the attached implement. The critical speed of the tractor with the implement was 3.26 times lower than that of the tractor with no implement on average. It is judged that the safety of the implemented tractor can be identified by using this study.

Preliminary investigations of ground failures triggered during the mid-November 2021 atmospheric river event along the southwestern British Columbia highway corridors

An unusually intense atmospheric river affected the southern coastal region of British Columbia in mid-November 2021. Flooding and several ground failures such as landslides and riverbank erosion caused significant damage and interrupted the main transportation corridors, including major highways and railroads, severing land connectivity between Metro Vancouver and the rest of Canada. In this short note, we summarize and describe slope and riverbank ground failures in the Lower Mainland and connecting corridors to the interior such as the Fraser Canyon and the Coquihalla Valley, with focus on those that produced damage on highways. Field observations are discussed in the context of potential future similar disasters in the region due to more frequent extreme climatic events associated with climate change.

Characteristics of Mining-Induced Slope Movement and Ground Behavior under Gully Landforms

Exploring the phenomenon of surface cracks and the abnormal phenomenon of ground behavior during coal mining under gully landforms, laboratory physical similarity simulation models were established to study the movement characteristics and ground behavior laws of working faces of different mining methods under gully landforms. The results indicate that in cases when a roadway is situated below the top of the slope, the corresponding deformation of the surrounding rock of the roadway is aggravated by the mining stress. Furthermore, when a roadway is located below the base of the gully, it is less affected by mining; thus, it could remain relatively stable. The ground behavior laws of working faces in gully geomorphology areas are associated with the position of the working face and the direction of working: when mining towards the gully, the ground behavior appeared relatively gentle and the surface slipped towards the gully; when mining away from the gully, the ground behavior appeared intense, the pressure was sudden and short, and with the increase in overburden thickness, the interval distance periodically decreased. When a working face passes through a gully, dumping of the hydraulic support should be prevented in the section of mining towards the gully; in sections of mining away from gully, the support strength should be strengthened to prevent the support and other equipment from being crushed. In actual mining, mining towards a gully should be adopted as much as possible in the stoping of the working face. In this way, the ground behavior is gentle, the interval distance periodical weight is longer, and the advance abutment pressure is small.

A Comparison of Two Felling Techniques Considering Stump-Height-Related Timber Value Loss

Harvest from plantations can provide both industrial wood and forest residues for bioenergy, including stumps. The literature suggests that the choice of cutting system can affect the division between industrial wood recovery and remaining stump volume. In this study, two felling techniques - motor-manual chainsaw and feller-buncher, were compared based on stump-height-related timber value loss for four ground slope classes: high, medium, low, and flat. The economic value loss of wood material for three products - sawlogs, pulpwood, and fiber-chip wood, was determined based on the estimated volume of stumps left in the woods. The results indicated that the average stump height for the motor-manual chainsaw and feller-buncher was 17.16 cm and 8.69 cm. The economic value loss of wood material per stump was higher in felling by manual chainsaw as compared to the feller-buncher operation (log: €0.60­, paper wood: €0.29­, fiber-chip: €0.15­). However, volume loss due to high stumps could contribute to wood for bioenergy if stumps are subsequently removed. Additional research is needed to evaluate the benefits and costs of stump removal for bioenergy as part of a total supply chain to provide both industrial wood and wood for bioenergy.

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.

Case history on excessively large displacements and remediation of pile-supported excavation in a sloping ground

Pile-supported excavations in urban region slopes can result in excessively large retaining wall and ground surface displacements if not strutted or tied back correctly. Such an example is presented in this study showing the details of investigation works, construction procedure, monitoring, and 3D numerical analysis of a deep excavation in a stiff clay slope. Total excavation depth ranged from 4.8 m to 5.3 m, with additional 2.0 m high vertical wall and 2.8 m high steep slope in the vicinity of the pile capping beam. Before reaching the bottom of the designed excavation, the maximum cumulative monitored wall displacements were 115.0 mm, while the cracks observed on the nearby uphill structures exceeded 5.0 mm in width. Detailed field inspections and the 3D numerical analysis were performed to investigate the displacement pattern of the pile wall and the adjacent soil and structures in the uphill area. The numerical model results were further used to define specific supporting measures to enable excavation and building construction. Supporting measures were presented, and their effectiveness was assessed. Finally, the lessons learned were summarized to prevent future failures of similar structures.

Effect of spatial variation of spoil material properties on slope displacements under rapid drawndown of pit lakes

In many European countries, lignite or brown coal is used as a fuel source in steam-electric power generation. Upon completion of mining activities, a reclamation plan is imperative to ensure environmental and social prosperity of local areas. Abandoned mine pits are often reclaimed by creating a pit lake. Reclamation of large lignite open pit mine sites may use large amounts of previous overburden materials or “spoils” to create the slopes of the pit lake. Spoils are anthropogenic materials with large spatial variation in properties, hence, considering mean values of shear strength and hydraulic parameters to assess stability and seasonal displacements will not fully simulate actual field conditions. This paper considers the effect of spatial variation on slope stability and ground movements during rapid drawdown events (a critical case) using coupled flow-deformation 2D finite element analyses, incorporating unsaturated soil suctions above the phreatic surface. Effects of heterogeneity and randomness of spoils on the response of the slope are considered through random field modelling and the Monte-Carlo simulation technique. Four lognormally distributed random variables (spoil cohesion, friction angle, void ratio, and permeability coefficient) are examined. The effect of spatial variability of spoils is shown to be important; a significant number of the random field analyses resulted in larger displacements compared to a benchmark deterministic analysis adopting uniform mean parameter values.