Ground Slope Research Articles

Studies on sliding stabilization solutions of a built site in a residential area

Abstract The paper presents a case study performed on a site for residential buildings, arranged by terracing on a sloping ground. The built site, subject to investigations, shows an obvious state of degradation downstream, manifested by the development of concentric cracks, penetrated deep, as a result of displacements/rotations produced in the massif of soil susceptible to sliding. The analyzed comparative solutions aim at achieving mechanical barriers developed in dep, taking the tensile efforts through reinforced soil works and improving the shear resistance of the soil.

Single pile in cohesionless soil in sloping ground under lateral loading

Pile foundations are adopted if a soil of low bearing capacity extends to a considerable depth or if the structure is heavy or the settlement due to the structure is large. It transfers the load to a strong, stable stratum of soil. The behaviour of soil in slope and piles embedded in it is an elaborated soil-structure interaction problem. This paper presents the results of experimental investigations on a single pile subjected to lateral load by varying relative density of soil in the horizontal and sloping ground with three different slopes of 1V: 2H, 1V: 2.5H and 1V: 3H. The lateral load carrying capacity of the pile is considerably decreased when the lateral load is applied in the direction of the slope. It is found that the lateral load carrying capacity of the pile is increased for higher relative density of sand and the lateral capacity of the pile is greater in flatter slope than in steeper slope. The effect of different slopes on normalized lateral load versus displacement for the lateral load applied in the direction along and against slope is quantified. A set of empirical equations are formulated to determine the deflection, fixity depth and moment for the pile in sloping ground.

Design and Behavioral Analysis of Multi storied RCC Moment Resisting Frame Using Linear Spectrum Analysis in Seismic Zone-IV of Indian Subcontinent

In this paper seismic response of (G+15)R.C. framed building is analyses for seismic load case by using STAAD-Pro software as per IS1893:2002 part-1.This paper consider different seismic parameter like seismic zone(IV), response reduction factor(R), importance factor(I)& other parameters like rock/soil type, structure type, damping ratio etc. This paper provides complete guidelines for STAAD-Pro software analysis & STAAD –Pro gives the results after run analysis in the STAAD output viewer which shows joint displacements, support reactions, member forces, base shear and lateral load. If we consider the concrete era of construction activities, the land is scarce, especially in metro cities. Even though if there is the availability of land it may be in the sloping ground, hillocks, or on land-filled areas, in such areas, there will be difficulty in the construction and design aspects. To maintain the slope of the strata, different degrees of such buildings step back towards the slanting slope and may likewise also have set back simultaneously. Hence in the present paper, an attempt has been made to study, the G+15 storey building assumed to be on flat ground and also on sloping ground with a 20-degree inclination. The model is considered to be a soft storey with infill walls and two different shear wall arrangements. The building has been modeled and analyzed in STADD PRO software with the response spectrum method of analysis. The study reveals that a model with a shear wall improves the performance of the structure in terms of displacement, drift, and time period apart from the fact that the structure is being constructed in normal ground or sloping ground. STAADPRO is one of the finest tools for the design of structures. In this project, we analyzed the G+15 building through response spectrum analysis to develop the economic design. IS: 1893 (Part I) for seismic design is utilized to perform the dynamic analysis. The results show that multistoried buildings are generally stiff for earthquake excitation as the modal participation factor is more than 75 percent. Keywords: STAADPRO, Response Spectrum Analysis, Storey drift, storey displacement and base shear.

გრუნტის წყლების გავლენა ფერდოს სტატიკურ მდგრადობაზე. დეპრესიის მრუდის განტოლება

The underground waters move in the slope massif of a homogeneous mountain rocks. It is demonstrated that the filtration forces are the main cause for the decreased soil strength and slope deformation that further causes landslides. It was found that calculating the variability of groundwater levels and the location of the depressive curve plays an important role in the slope sustainability analysis. To solve this problem, the movement of the filtration water flow is considered within the slope of a homogeneous soil, which relies on the water-permeable cliffy bed sloping at an angle  to the horizon. A common differential equation for the motion of the filtration water flow is deduced and reduced to the first-order linear equation, which is satisfied by the equation of the depression line. The method to draft a theoretical depression curve by using the solution of the differential equation is discussed. Based on this method, several typical points on the depression curve were selected. By using different values of geometrical parameters and ground characteristics of the slope, the coordinates of the typical points were determined. Auxiliary graphs were construed based on the results obtained by the numerical method to determine the coordinates of the outcrop of the depression curve on the slope surface and midpoint. The solution of a test example is given for illustration purposes. As the filtration water moves through the ground of the mountain rock slope, the impact of filtration forces or hydrodynamic pressure on the reduction of the slope ground stability is substantiated. Additional shear forces are taken into account in the calculation of the slope stability: hydrostatic and hydrodynamic pressures. The impact of the sums of these two forces results in the decreased ground mass strength, landslides and avalanches. For the slope stability analysis, the condition of the stability of the unit volume of the ground particle on the slope surface is considered. The formula to calculate the shear strength coefficient is deduced.

Habitat Suitability Modeling of Rare Turkeybeard (Xerophyllum asphodeloides) Species in the Talladega National Forest, Alabama, USA

This study focused on the rare and threatened plant species eastern turkeybeard (Xerophyllum asphodeloides (L.) Nutt.) and its presence or absence in the Talladega National Forest in Alabama, USA. An ensemble suitable habitat map was developed using four different modeling methods (MaxEnt, Generalized Linear Model, Generalized Additive Model, and Random Forest). AUC evaluation scores for each model were 0.99, 0.96, 0.98, and 0.99, respectively. Biserial correlation scores for models ranged from 0.71 (GLM) to 0.94 (RF). The four different models agreed suitable habitat was found to cover 159.57 ha of the land. The ground slope variable was the most contributive variable in the MaxEnt and RF models and was also significant in the GLM and GAM models. The knowledge gained from this research can be used to establish and implement habitat suitability strategies across the Talladega National Forest and similar ecosystems in the southern United States.

Effect of Liquefaction Induced Lateral Spreading on Seismic Performance of Pile Foundations

Seismically active areas are vulnerable to liquefaction, and the influence of liquefaction on pile foundations is very severe. Study of pile-supported buildings in liquefiable soils requires consideration of soil-pile interaction and evaluation of the interaction resulting from movement of soil surrounding the pile. This paper presents the results of three-dimensional finite difference analyses conducted to understand the effect of liquefiable soils on the seismic performance of piles and pile groups embedded in stratified soil deposits using the numerical tool FLAC3D. A comparative study has been conducted on the performance of pile foundations on level ground and sloping ground. The soil model consists of a non-liquefiable, slightly cemented sand layer at the top and bottom and a liquefiable Nevada sand layer in between. This stratified ground is subjected to 1940 El Centro, 2001 Bhuj (India) earthquake ground motions, and harmonic motion of 0.3g acceleration. Parametric studies have been carried out by changing the ground slope from 0° to 10° to understand the effects of sloping ground on pile group response. The results indicate that the maximum bending moments occur at boundaries between liquefiable and non-liquefiable layers, and that the bending moment increases with an increase in slope angle. The presence of a pile cap prevents horizontal ground displacements at ground level. Further, it is also observed that the displacements of pile groups under sloping ground are in excess of those on level ground due to lateral spreading. Doi: 10.28991/CEJ-SP2021-07-05 Full Text: PDF

Verifying the Lifting and Slewing Dynamics of a Harvester Crane with Possible Levelling When Operating on Sloping Grounds

This paper focuses on the force and torque load of a harvester hydraulic crane employed on sloping grounds, both levelled and not levelled. Field research was conducted for this purpose and the results were compared with a dynamic analysis of the crane in MSC Adams. It was found that levelling the slewing platform of the crane is necessary for use on sloping grounds, primarily because the effect on the force and lifting torques is reduced. The research showed that when the slope of the slewing gear is up to −12°, the lifting torque reaches a higher maximum lifting force than when the slewing gear is in a horizontal position (0°). As part of the theoretical verification by a dynamic analysis of the crane and the AH6 machine, a different pressure was detected in the lifting cylinder of the crane compared to the field research. The total deviation between the simulation and the field research was 9.82%. The slewing torque of the hydraulic crane without the slewing bearing being levelled can be characterized 97.38% by a parabola whose vertex is located in front of the front part of the machine and falls as the crane moves left or right. Overall, it can be determined that when the crane rotates up a slope, whether it is from left or right, the slewing torque reaches the lowest values, and its value increases as the crane gets closer to the front of the machine (along the longitudinal axis of the machine). This change in the slewing torque is then characterized by a parabola. Furthermore, an effect was observed of the slewing gear slope on the lifting torque, which reached higher values in a tilted position than on a flat surface.

Forecast of Thermal Mode for the Slope Fill-Up Ground, Considering the Operation of Seasonal Cooling Units in Cryolithic Zone Conditions

The article is concerned with the solution of the issue of freezing and stabilization of negative thermal mode for the slopes made of fill-up ground, which are held by a gabion wall in cryolithic zone conditions. To estimate the efficiency of artificial freezing of the slope ground, a mathematical 3D model of heat-exchange processes was worked out, which takes into account the phase change of moisture, freezing temperature, length of cooling devices, their quantity and location, the annual cycle of ambient air temperature and ground bedding. The model takes into account geometrical parameters of the slope and impact of daylight surface. The issue had been solved with numerical technique of finite differences. The calculations indicated the efficiency of implementation of seasonal cooling units for increasing of the fill-up slope stability. Their implementation results in progressive accumulation of cold in its ground. By the end of the fourth year of freezing, the whole mass of the fill-up slope ground turns into a frozen state. When seasonal cooling units were switched off in next years, the frozen area in the fill-up slope remains the same and thermal mode of the slope ground becomes a stable periodic cycle, i.e. expected seasonal temperature oscillations take place.

Subject-Independent, Biological Hip Moment Estimation During Multimodal Overground Ambulation Using Deep Learning

Estimating biological joint moments using wearable sensors could enable out-of-lab biomechanical analyses and exoskeletons that assist throughout daily life. To realize these possibilities, this study introduced a subject-independent hip moment estimator using a temporal convolutional network (TCN) and validated its performance and generalizability during multimodal ambulation. Electrogoniometer and simulated IMU data from sixteen participants walking on level ground, ramps and stairs were used to evaluate our approach when benchmarked against a fully-connected neural network, a long short-term memory network, and a baseline method (i.e., using subject-average moment curves based on ambulation mode and gait phase). Additionally, the generalizability of our approach was evaluated by testing on ground slopes, stair heights, and gait transitions withheld during model training. The TCN outperformed the benchmark approaches on the hold-out data (p < 0.05), with an average RMSE of 0.131±0.018 Nm/kg and R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 0.880±0.030 during steady-state ambulation. When tested on the 20 leave-one-out slope and stair height conditions, the TCN significantly increased RMSE only on the steepest (+18°) incline (p < 0.05). Finally, the TCN RMSE and R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> was 0.152±0.027 Nm/kg and 0.786±0.055, respectively, during mode transitions. Thus, our approach accurately estimated hip moments and generalized to unseen gait contexts using data from three wearable sensors.

Gait Design and Analysis of Quadruped Crawling Robot Climbing Over the Raised Terrain of Slope

Background: Quadruped crawling robots face challenges when working in the raised terrain of a slope. The robot is affected by gravity and gait under this terrain. The ground reaction force on its hind legs is relatively large. This has strict requirements for the structure and gait planning of the quadruped crawling robot. Objective: Aimed at the problem of a large ground reaction force on the rear legs of the quadruped crawling robot when crawling on the raised terrain of a slope, a slope-triangular gait walking strategy for quadruped robots based on a layered CGP gait generation method is proposed. Methods: Three-dimensional model of the quadruped crawling robot is created in SOLIDWORKS. The kinematic model is established, and the foot position vector is obtained. Considering the characteristics of the raised terrain of a slope, slope tripod gait and hierarchical CPG slope tripod gait generator are proposed. Comparative simulation of sloped tripod gait and flat tripod gait, the slope tripod gait with and without the gait generator is carried out by Adams programming. Results: When the quadruped crawling robot adopts slope tripod gait and flat tripod gait respectively, the centroid displacement curve, foot speed curve and foot contact force curve are compared. When the quadruped crawling robot adopts the slope tripod gait and does not adopt the slope tripod gait, the body posture curves of the two are compared. The result proves that the tripod gait walking strategy is feasible. Conclusion: The slope tripod gait walking strategy can improve the impact resistance of the quadruped crawling robot on sloped high ground. The gait design and motion analysis process of the robot can provide a reference for other quadruped crawling robot devices.

Review Paper on Effect of Wind on Building Resting on Sloping Ground and Analysis Using Etabs

Abstract: Wind has paramount importance in the field of civil engineering. Due to urbanization and increasing population density high rise building are coming up in large number. Therefore building frame resting on sloping ground and its analysis and design becomes essential so that the structure becomes more durable and serviceable. It is possible by various special programs and software. Software helps to design light weighted structure with good service life. This project studies the effect of wind velocity and structural response of building frame on sloping ground. For that three different building heights (G+8, G+10 and G+12) are considered. Ground slope (0°, 5°, 10° and 15° ) and wind zones (33, 39, 44, 47 and 55 m/s)has been considered. Comparative study of various parameters such as shear force, bending moment drift with the help of ETABS software gives appropriate result. Keyword: sloping ground, shear force, bending moment, wind zone, ETABS

EARTHQUAKE RESPONSE STUDY OF MULTI-STORIED RCC BUILDING WITH FVD ON SLOPING GROUND

Damping performs essential function in format of earthquake resistant structures, which lower the change of the shape when they are subjected to lateral loads or earthquake. In the existing study fluid viscous dampers (FVD) are used to consider the response of RCC buildings on sloping ground. The important challenge of a structure is to endure the lateral loads and switch them to the foundation and to control the story displacement. In order to make structure earthquake resistant, (FVD) have been used. The building is modeled in ETAB 2018 and modeled with different location of FVD. After the study results show building with fluid viscous dampers (FVD) at diagonal bracing shows better performance.

Multi-objective optimization of a CSP-based dish Stirling field layout using Genetic Algorithm and TOPSIS method: Case studies in Ouarzazate and Madrid

CSP systems have experienced significant growth with great ability to supply clean and eco-friendly electrical power. In this paper, multi-objective optimization is carried out to design the most energy and cost-effective Solar Dish Stirling (SDS) power plant. Meteorological data from two different sites have been considered to simulate the technical and economical performances of 10 MW SDS power plant. Two main energy and economic conflicting objective functions were considered with the ultimate goal to maximize of the annual Capacity Factor and minimize the Total Cost of Site Improvements simultaneously. Several parameters such as the separation distance between collectors, ground slope, slot gap height and width have been parametrically assessed to find out effects on the Capacity Factor and the Total Cost of Site Improvements. First, a third-order multiple non-linear surrogate model was constructed. The model validity was demonstrated by the R-square values which were found to be 0.995 and 0.9964 for Ouarzazate and Madrid, respectively. Then, multi-objective optimization using Elitist Non-Dominated Sorting Genetic Algorithm (NSGA-II) has been applied to address the trade-off between the two objective functions. The obtained Pareto Front was identified accordingly and final optimal solution was determined using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision-making method. Final optimal solution corresponded to Capacity Factor (CF) values of 22.99% and 12.91% and a Total Cost of Site Improvements (TCSI) of 2.69 M$ and 2.60 M$, for Ouarzazate and Madrid, respectively.

Operation Energy Consumption Study on Reel and Polyethylene Tube of a New Hard Hose Traveler

To solve the problems of higher energy consumption and lower intelligence of traditional hard hose travelers, a new hard hose traveler with the function of electric drive and self-propelled is developed in this paper. The operational energy consumption of a reel and a polyethylene tube is an important part of hard-hose traveler energy consumption. In this paper, based on the JP50-180 hard hose traveler, the required pulling force and energy consumption at the reel and tube operation are theoretically and experimentally obtained. The aforementioned provides support for reducing energy consumption in the future. The influencing factor that affects the energy consumption of the reel rotation is the tube length, and the influencing factors that affect the energy consumption of the tube sliding are the ground slope, soil moisture content, and tube length. A calculation model for the dynamic change of the pulling force and energy consumption of the reel and tube operation is proposed in this study. Through theoretical analysis, maximum pulling tension and cumulative energy consumption requirements for the for reel rotation are 278.6 N and 15120.83 J, respectively. Furthermore, the requirements for the tube sliding are 1372.86 N and 123,456.96 J. Through test analysis, the maximum pulling tension for the tube sliding is between 1258.3 N and 1773.3 N, while the maximum pulling tension for reel rotation is 285.05 N. Under the same influencing factors, the deviation rates between theoretical and testable energy consumption for the reel rotation and tube sliding are 2.3 and 8.3%, respectively. The pulling force and cumulative energy consumption required for the reel rotation and tube sliding both increase with an increase in their influencing factors. The operating costs of the tube one-time unrolled are approximately 0.0185 CNY. Combined with the mobile resistance of the electric tracked vehicle, the power configuration of this new hard hose traveler is provided by two servo motors with a power of 5500 W each.

Kinematic response of single vertical and batter piles to bidirectional ground motions in liquefiable soil

Kinematic responses of single fixed head vertical and batter piles in liquefiable soil under bidirectional ground motions have been studied with fully-coupled three-dimensional nonlinear dynamic analyses. Pressure dependent multi-yield constitutive model has been adopted for modeling the liquefiable sand behavior. The variable permeability of saturated sand during the process of liquefaction process has also been considered. The analyses are carried out for combinations of bidirectional earthquake loading conditions. For this, combination of longitudinal and transverse ground motions as well as combination of longitudinal and vertical motions are considered. The responses of the soil-pile systems under liquefying ground conditions, subjected to these bidirectional ground motions, are compared with the unidirectional loading conditions. Further, the effect of sloping ground on the response of the piles under bidirectional ground motions is also investigated. The developed sectional forces in both vertical and batter piles are lesser under bidirectional motions in comparison to unidirectional ground motion in both level and sloping grounds. However, the pile displacement is more in case of sloping ground under bidirectional ground motions comparing to unidirectional motion.

A modified pressure dependent multi-yield surface model for simulation of LEAP-Asia-2019 centrifuge experiments

A modified flow rule has been introduced into a pressure dependent multi-yield surface model for predicting the liquefaction of laboratory soil element tests and centrifuge experiments. The plastic potential function within the contractive phase in the flow rule of the constitutive model has been adjusted for better estimating the accumulation rate of plastic volumetric strain and the generation rate of excess pore water pressure. The modification of flow rule was mainly employed for achieving successful calibration of model parameters with the laboratory soil element tests and obtaining better predictions of the seismic response of LEAP-Asia-2019 centrifuge model tests. A calibration process of the constitutive model was firstly performed through numerical simulation of cyclic torsional shear tests of Ottawa F-65 sand samples with different relative densities under various cyclic stress ratios, and the estimation procedures of new parameters are provided. Then Type-B and Type-C numerical simulations were carried out for centrifuge experiments of a mildly sloping ground of Ottawa F-65 sand subjected to ramped sinusoidal input motions. The modified constitutive model could reasonably simulate the seismic response for almost all centrifuge model tests using the same set of model parameters.

Characteristics of landslides triggered by the 2013 ML6.5 Nantou, Taiwan, earthquake

Earthquake-triggered landslides are common disasters of active mountain belts. Due to the lack of earthquake-triggered landslide inventory in Taiwan, it is not intuitive to observe spatial relationships and discover unique patterns between landslides and essential triggers. We examined strong earthquake events in Taiwan after the 1999 Mw7.6 Chi-Chi earthquake and targeted the 2013 ML6.5 Nantou earthquake to create the landslide inventory. We adopted two Landsat-8 satellite images before and after the event to detect landslides, and incorporated a 20-m DEM and rock type data of Taiwan to represent key factors triggering earthquake-induced landslides such as peak ground acceleration (PGA), lithology, slope roughness, slope, and aspect. Based on the analysis of the density of landslides, there are strong correlations between the landslide occurrence and seismic and geomorphic factors. Furthermore, we noticed that the landslide aspects have a systematic tendency towards the northeast, which is not correlated with the dip directions and wave propagation directions. Instead, we found that the northeastward landslide aspect is more associated with the westward–southwestward surface movement at the landslides. We found that the included angles between the landslide aspects and the displacement directions for all the landslides are ~ 100°–180°. The relationship indicated that the coseismic deformation of the Nantou earthquake may play a role in the landslide distribution.Graphical

Is There an Association Between Salivary Cortisol and Dropping Out of Inpatient Substance Addiction Treatments? A Prospective Repeated Measures Study.

Several studies have found an association between salivary cortisol levels and dropping out of inpatient substance addiction treatment programs. The results are mixed due to variations in the study design and the lack of standardized routines for cortisol assessment. The aim of this study was to investigate whether there was (1) an association between salivary cortisol levels and dropping out from inpatient substance addiction treatments; (2) higher predictive validity for dropout in one of the cortisol indexes: Area Under the Curve with respect to ground (AUCG) or Daily Cortisol Slope (DCS); (3) an interaction effect with time for each cortisol index; and (4) different dropout rates for sex and patients in short-term versus long-term treatment programs. This was a prospective, repeated-measures observational study. Patients (n = 173) were recruited from 2 inpatient facilities in the central region of Norway between 2018 and 2021. Salivary cortisol was measured 4 times during the treatment period, with 8 samples collected over 2 consecutive days at each time point. Cortisol levels were calculated using the cortisol indices AUCG and DCS. Dropout was used as the outcome measure at each time point. Associations were calculated using a logistic linear regression. The results suggest a main effect of AUCG, whereby higher levels reduce dropout risk (OR = 0.92, P = .047). An interaction with time in treatment also revealed a higher dropout risk (OR = 1.09, P = .044) during week 4 of the treatment, depending on the AUCG. These results support using AUCG as the recommended index when assessing cortisol, and that the relationship between cortisol levels and length of treatment should be further investigated.

Twoaxistracking – a python package for simulating self-shading of two-axis tracking solar collectors

Self-shading in fields of two-axis tracking collectors typically ranges from 1% to 6% of the annual incident irradiation. It is thus essential to account for shading in order to obtain accurate yield estimates and financing for such solar projects. The present study presents the free and open-source Python package twoaxistracking for simulating self-shading in fields of two-axis tracking collectors. The package is freely available at: https://github.com/pvlib/twoaxistracking. The main steps of the method and mathematical formulation are described. Additionally, a demonstration of how to use the package is presented. The shading calculation method excels over previous methods found in the literature in that it can:•Handle arbitrary aperture geometries and distinguish between the total and active areas.•Account for sloped ground and collectors with different heights within the same field.•Reduce computation time by skipping calculations at high solar elevation angles.

Seismic performance of step back, step back set back and set back buildings in sloping ground base

This paper presents the structural behavior of buildings located in the sloping ground level subjected to seismic load. Three different categories of building from three to five storey are considered for the numerical modelling namely set back building (SB), step back building (SBB) and step back set back building (SBSB). The dynamic response of different buildings are analyzed and compared to assess the seismic vulnerability associated with each buildings. The seismic vulnerability is accessed by comparing the base shear, drift, displacement and torsion factor values. Linear static method is used for the calculation of earthquake load using ETABS. It is observed that SBB and SBSB are highly affected by torsion compared to the SB building. It is desirable to use shear wall in periphery of the bottom storey to improve seismic performance of building. The results in this paper can be employed for construction of buildings with seismically active sloping ground.