Kind Of Slope Research Articles

Analytical Analysis of Infinite Heterogeneous Slope Stability considering Suction Influence

Soil heterogeneity in an infinite unsaturated slope increases the difficulty of analysing its stability. A common method of modelling the spatial variability in the slope stability analysis is to use random fields together with Monte Carlo simulation, but this requires an impressive amount of computational efforts. To reduce the computing time, this paper develops an analytical approach to study the stability of infinite heterogeneous unsaturated slopes. The analytical method provides a newly time-efficient way of analysing such kinds of slopes. It has been used to investigate the stability of four different kinds of unsaturated soil slopes. Meanwhile, the influences of the correlation between the strength parameters and the autocorrelation length of the strength parameters are investigated. The analysed results show that the suction has influences on the distribution of the FOS for both homogeneous slopes and heterogeneous slopes. In addition, the correlation coefficient between the strength parameters and the autocorrelation length of the strength parameters affects the mean and standard deviation of FOS for homogeneous slopes and the probability of failure for heterogeneous slopes.

Stability Assessment of Multi-Stage Slopes Considering Local Failure

The analytical method for slope stability analysis requires a collapse mechanism in advance. The collapse mechanism for a multi-staged slope is generally assumed to be overall failure, whereas this kind of slope may suffer from local failure. However, a local failure is rarely reported in the previous research for multi-staged slopes, which may result in an overestimate for slope stability. To this end, local failure is incorporated into the collapse mechanism for the first time, so as to develop a complete approach to assess the stability of multi-stage slopes. The modified pseudo-dynamic method is conducted to properly account for seismic effects. Thanks to the limit analysis method and strength reduction technique, the safety factor of a multi-stage slope is obtained. The result obtained by the presented approach shows a good agreement with that of previous literature and numerical calculations. The collapse mechanism of multi-stage slopes is studied, and the safety factor is presented schematically for a wide range of parameters. The results show that the local failure for a multi-stage slope often manifests under the intense seismic effects.

Study on smoke diffusion and ceiling temperature distribution in the V-shaped tunnel fire scenario

In this paper, numerical simulations are conducted to study the smoke diffusion characteristics in the V-shaped slope tunnel with different slopes. The smoke diffusion characteristics and the ceiling temperature distribution with three kinds of heat release rates (HRR) and three kinds of slopes are considered without mechanical ventilation. The simulation results show that the smoke diffusion symmetrically on both sides of the symmetrical V-shaped tunnel. The smoke diffusion speed is mainly affected by the HRR, while it is less affected by the slope. The smoke diffusion speed increases with the increase of HRR. The maximum ceiling temperature increases with the increase of HRR and decreases with the increase of slope. The HRR is constant, the ceiling temperature decreases with the increase of the slope within 150 m away from fire source. Beyond 150 m from fire source, the ceiling temperature distribution are in opposite tendency and the overall temperature has a little difference between both sides of V-shaped tunnel.

Analysis and Recognition of Human Lower Limb Motions Based on Electromyography (EMG) Signals

Background: This paper focuses on the characteristics of lower limb EMG signals for common movements. Methods: We obtained length data for lower limb muscles during gait motion using software named OpenSim; statistical product and service solutions (SPSS) were utilized to study the correlation between each muscle, based on gait data. Low-correlation muscles in different regions were selected; inertial measurement unit (IMU) and EMG sensors were used to measure the lower limb angles and EMG signals when on seven kinds of slope, in five kinds of gait (walking on flat ground, uphill, downhill, up-step and down-step) and four kinds of movement (squat, lunge, raised leg and standing up). Results: After data denoising and feature extraction, we designed a double hidden-layer BP neural network to recognize the above motions according to EMG signals. Results show that EMG signals of selected muscles have a certain periodicity in the process of movement that can be used to identify lower limb movements. Conclusions: It can be seen, after the recognition of different proportions of training and testing sets that the average recognition rate of the BP neural network is 86.49% for seven gradients, 93.76% for five kinds of gait and 86.07% for four kinds of movements.

Research on the Influence Mechanism of the High-Steep Slope on the Deformation Characteristics of Bridge Substructure

With the development of the Chinese railway, the high-steep slope is irreversible to be faced; especially under severe conditions such as heavy rainfall and earthquake, this kind of slope is prone to geological disasters, which seriously affects the safety and stability of the bridge substructure. Aiming to this, long-term monitorization and numerical analysis were carried out in this research, and the influence mechanism of the high-steep slopes on the stress and deformation characteristics of the bridge structure was studied. The research results show that under the effect of rainfall and earthquake, the original stress balance in the high-steep slope is broken, and the possibility of landslide thrust increases; under the comprehensive impact of residual landslide thrust, traction force at slope foot, vertical gravity of bridge slab and vehicle, and the bridge cap will deform. Besides, the deformation of the bridge pier exceeds the allowable lateral displacement of the top of the bridge pier, reaching 111.7%∼112.4% of the limit, which seriously affects the stability of the bridge structure and the safety of the railway service. Therefore, by increasing the support strength of the slope foot and the diameter of the bridge pile foundation, the traction force of the slope foot can be reduced, and the sliding resistance of the bridge pile foundation can be improved so as the safety of the bridge structure can be promoted.

Research Progress on Dynamic Stability of Layered Rock Slope

The analysis of failure mechanism and stability of rock slope under seismic load has become an important research content in geotechnical engineering, and the layered structure is the most common among the rock masses composing the slope. In this paper, the layered rock slope is divided into three types, i.e., horizontal, bedding and anti-dipping, according to the dip angle of rock layer in the layered slope. The influence factors, failure modes and dynamic stability of the three kinds of slope under seismic action are systematically summarized and reviewed in detail, and the problems to be studied and the possible research approaches are pointed out in the light of the current research methods.

ANALYSIS OF SLIDING DEFORMATION MECHANISM OF A TYPICAL HIGH CUTTING SLOPE IN THE MOUNTAIN OF FUJIAN PROVINCE

The K85 slope is a typical high cutting slope in the mountain of Fujian province, which is located in an expressway of Fujian province. During the slope treatment, there appeared cracking deformation and partially collapse, and formed a landslide disaster. The landslide affected the smooth opening of the line. So, for the similar slopes, it is great significance to study the deformation mechanism of this slope. In this paper, by analyzing the geological environment of the slope and the deformation of the slope excavation, the deformation and failure mechanism is described. It indicates that the deformation and failure mode is that the overlying weathered rock mass along the underlying rock surface caused the sliding deformation and damage. It uses finite element numerical simulation to analyze the steady-state of design schemes and actual construction conditions. And combining with on-site monitoring results, it confirms the deformation mechanism of these slopes. Meanwhile, it analyzes the risk prevention and control nodes about the treatment process in this kind of slope. Finally, the slope prevention and reinforcement scheme is optimized for the instability landslide. And, it is reasonable and feasible to verify the scheme by numerical simulation and new monitoring results.

Evaluation method of highway slope stability based on deep displacement curve characteristics

Taking the slope of Yunnan Wuyi Expressway as a case study, the typical geologic generalization models of three kinds of slopes were established by means of statistical analysis. The limit equilibrium method, finite element numerical simulation method, and deep displacement curve type analysis are combined to evaluate the slope stability under various working conditions in a comprehensive way. The relationship between the deep displacement characteristic curve and slope stability, and a slope stability criterion is established based on the characteristics of deep displacement curve. This method is a supplement to the current Chinese standards on slope stability evaluation. According to the analysis to typical slope projects in central Yunnan, this evaluation method is simple and feasible, which is suitable to evaluate the stability of various types of highway slopes in central Yunnan in China.

The Application of Ecological Treatment Technology of Bolt and Lattice Beam in Highway Mountain Slope Support

In this paper, the ecological control technology of bolt and lattice beam is used to effectively control the slope of Highway Mountain. According to the engineering geological characteristics of the slope, the cause of the possible failure of the slope is analyzed. The code for design of building slopes is used to optimize the reasonable design parameters. The ecological treatment scheme of the shrubs planted in the bolt + lattice beam + sorghum trough is proposed. The scheme can effectively reduce the destruction of the masonry construction to the surrounding environment, reduce the erosion and infiltration of the slope surface, and effectively enhance the stability of the slope. The vegetation in the sorghum groove of the slope can be well coordinated with the surrounding vegetation. It is an effective plan for the new ecological control of the mountain slope, which can provide some reference for the reinforcement of the same kind of slope.

Analysis of the Influence of Anti-sliding Pile on Slope Stability Under Action of Groundwater

In order to effectively reinforce the slope of rich groundwater, the reinforcement effect of anti-slide pile on this kind of slope is studied through OptumG2 simulation. This paper firstly simulates the influence of groundwater on the slope of anti-slide piles, and then the position of optimal pile position on different slope under groundwater is explored. The results show that the groundwater has a great influence on the slope of the reinforced slope, and the best pile position of different slope is different.

Molecular dynamics study of bubble nucleation on a nanoscale

With the rapid development of nanotechnology, nucleate boiling has been widely applied to the thermal management of nanoelectronics, owing to its highly-efficient heat transfer characteristics. Considering the scale effects, such as temperature jump at solid-liquid interface, a further study of nucleation boiling mechanism at a microscopic level is needed. At present, extensive studies have been carried out for providing a significant insight into the formation of nano-bubbles in a nanoscale thermal system, but the effect of heat transfer efficiency affected by the surface wettability on bubble nucleation over solid substrate is rarely available in the literature. Therefore, in this paper, the effect of surface wettability on the initial nucleation process and growth rate of bubbles are investigated and the mechanism of bubble nucleation on a nanoscale is analyzed, by the molecular dynamics simulation. The modified Lennard-Jones potential is used for investigating the solid-liquid interaction. Changing the potential parameters <i>α</i> and <i>β</i> can obtain different surface wettability. The atomic sites, liquid density profiles and bubble nucleus volumes are computed to compare the processes of bubble nucleation on different surfaces. The variation of liquid temperature, potential and absorbed heat flux with heating time are evaluated to explore the mechanism of bubble nucleation. The simulation results show that the surface wettability influences the bubble nucleation and heat transfer at liquid-solid interface significantly. On the one hand, the bubble nucleation is promoted by properly increasing the liquid-solid interaction, which is distinctly different from the existing classical theory related to nano-bubble preferably formed on a hydrophobic surface. This is because the thermal resistance of the solid-liquid interface on a nanoscale cannot be neglected. The interface thermal resistance will decrease with the increase of wettability. Therefore, the heat transfer efficiency is higher for a stronger liquid-solid interaction so that the liquid over the hot wall obtains more energy to make bubble nucleus generated earlier. On the other hand, the surface wettability also influences the bubble growth rate. The stronger the liquid-solid interaction, the faster the bubble grows. When the volume of bubble reaches a certain value, a vapor film is formed on the substrate, leading to film boiling. Furthermore, it also illustrates that initial heat flux increases with time. In this stage, the heat flux curve shows two kinds of slopes, corresponding to the occurrence of evaporation and bubble nucleation, respectively. Then, after a certain time, the heat flux profile presents a declining trend, indicating a change into film boiling.

Analysis on Dynamic Response Characteristics of Consequent Rock Slopes

The dynamic stability issue of consequent rock slopes has been paid wide attention by scholars both at home and abroad, because this kind of slope is more likely to form a buckling failure under seismic loading. In this paper, in-depth researches focused on the dynamic stability problem of consequent rock slope have been launched by using the FLAC3D software. The numerical analysis is performed based on the slope model test of key laboratory of engineering geomechanics (EGL). The simulation and experimental results are in good agreement, which verifies that it is feasible to analyze the slope dynamic stability problem by using FLAC3D. Finally, the dynamic response characteristics of consequent rock slope are obtained through compare analysis of the test results and the results of numerical analysis.

Play types, geologic characteristics and exploration domains of lithological reservoirs in China

Abstract By dissecting thirty-six representative oil-gas reservoirs and analyzing accumulation conditions of giant oil and gas provinces in four prototype basins, including the Songliao Rift and Depression Basin, the Mesozoic Ordos Depression Basin, the Bohai Bay Rift and Depression Basin, the Mesozoic Junggar Depression Basin, the West Sichuan Foreland Basin and the Tarim Craton Basin, the hydrocarbon plays classification scheme of lithologic reservoirs is established and improved from the perspective of oil-gas accumulation zone and exploration target. The results reveal the accumulation characteristics and controlling factors of lithologic reservoirs including three kinds of slopes, three kinds of sag centers, three kinds of hydrocarbon accumulation assemblages and multiple genetic types. Based on the understandings on reservoir formation mechanisms and enrichment regularities of different hydrocarbon provinces, six major assessment indexes, parameter system and grading standard of lithologic plays are established, including hydrocarbon source rock condition, transportation pathway, reservoir condition, reservoir-cap assemblage, fluid property, and time-space configuration etc. Through comprehensive analysis of burial history, hydrocarbon-generation history, digenesis history, tectonic history, trap-forming history and accumulation history, plays of lithologic reservoirs are evaluated and optimized. The results show that the middle-shallow layers in the slope zones of the Songliao and Bohai Bay Basins oil-rich sags, the Mesozoic in the Ordos Basin, the Permian-Jurassic in the Junggar Basin, etc. are the major oil exploration areas in the future, with oil resources of about 42×10 8 t–67×10 8 t; the deep volcanic rocks of the Songliao Basin, the Carboniferous of the Junggar Basin, the Cambrian of the Tarim and Sichuan Basins, the Permian-Triassic reefs and shoals within the platform and on the platform margin of the Sichuan Basin are the major gas exploration areas in the future, with gas resources of about 1.5×10 12 m 3 −2.0×10 12 m 3 .

Solutions for stability of anchored earth slopes subjected to seismic loading

The limit analysis approach is paid more attention to in the stability analysis of slopes subjected to seismic loading. However, the solutions obtained from the approaches are in general limited to a designated slope or the same kind of slopes. It seems that a wide applicability of the solutions in their present form is rather difficult. Based on the kinematic theorem and the assumption of combined log-spiral rotational failure mechanism, the integral formulation for expressing the rate of external work rate due to soil weight and seismic loading is derived under the framework of pseudo-static method considering the complex geometrical configurations and the multilayer soils in slopes with multi-row anchors. Further, the work-energy balance equation is established, and the analytical expressions for the global factors of safety (FS) and the yield acceleration coefficient of anchored slopes are obtained by using the strength reduction technique combined with the optimization method. Moreover, the permanent displacement with Newmark's method is also solved. Several representative examples are employed to validate the analytical solutions, and some comparisons of the FSs and the corresponding critical sliding surfaces obtained by various methods are also made. The results show that the analytical approach can yield the high-accuracy solutions and is widely applicable to the seismic stability analysis of complex slopes with multi-row anchors. Finally, a practical case is analyzed using the proposed approach. ©2016, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.

Effects of soil crust and crop on runoff and erosion in Loess Plateau

Soil crust formed after rainfall has a strong influence on soil erosion, water use, and crop growth on sloping farmland. To study the effect of soil crust on sloping farmland on runoff amount and erosion sediment yield, the soil crust on sloping farmland has been studied in this paper for plantings of corn, soybeans, millet, and winter wheat. Using an outdoor rainfall simulator, the influence of soil crust on runoff rate and sediment yield on sloping farmland covered by crops has been observed. The results revealed that soil crust thickness was increased after rainfall and soil crust coverage showed little change after rainfall. Soil crust had a significant impact on runoff and sediment yield on sloping farmland. Slopes with soil crust showed higher runoff rate and less soil loss than slopes without soil crust. On slopes planted with four crops (corn, soybeans, millet, and winter wheat), runoff rates on slopes with soil crust were respectively 20%, 25%, 25%, and 21% higher than on slopes without soil crust; sediment yield on slopes with soil crust was respectively 15%, 14%, 14%, and 8% lower than on slopes without soil crust. Crops enlarged the runoff difference between the two kinds of slope and decreased the sediment yield difference between them. Crop growth enhanced these differences in runoff and sediment yield between slopes with and without soil crust.

Time-History Analysis of Tibet Gravel Slope

In order to obtain the Tibet gravel slope’s response under earthquake, using ABAQUS analysis this kind of slope and get the peak acceleration on the key elements along the slope height. Found that the result can truly gave the max acceleration during earthquake and the acceleration distribution of the slop.

Design and Autonomous Control of the Active Adaptive Suspension System of Rudra – Mars Rover

Semi or completely autonomous unmanned vehicles, remotely driven or controlled through artificial intelligence, are instrumental to foster space exploration. One of the most essential tasks of a rover is terrain traversing which requires the need of efficient suspension systems. This communication presents a suspension system giving degrees of freedom to every wheel with the help of linear actuators connected through bell crank levers. The actuation of linear actuators directly varies the height of every wheel from the chassis hence offering articulation to the rover. A control system is developed offering an algorithm for its autonomous actuation. This system proves instrumental for leveling of the chassis where any kind of slope, roll or pitch, may impute abstaining of payloads from efficient working. This was tried and tested successfully as a part of the rover developed by Team RUDRA from SRM University, INDIA (first Team from Asia and finishing at the fifth position) at University Rover Challenge 2013, held at UTAH, USA in May-June.

Experimental Study on Effect of Longitudinal Ventilation Velocity and Slope on Smoke Movement in Tunnels

The slope effects on the movement of internal smoke cannot be ignored. Fire experiments in a small scale tunnel are conducted in order to observe the smoke movement in a tunnel with three kinds of slope (0%, 3% and 5%) under different longitudinal ventilation velocity, then find the correlation between smoke diffusion velocity and longitudinal ventilation velocity, and slope in tunnel by numerical fitting and dimensional analyses, finally conclude:(1) as longitudinal ventilation velocity increases, smoke diffusion velocity gradually decreases; (2) when longitudinal ventilation velocity is smaller, with the increase of slope, smoke diffusion velocity is gradually increasing; (3) when longitudinal ventilation velocity is large, slope to smoke diffusion velocity is not affected. These quantitative conclusions provide fire Prevention of the tunnel in city with a reference.

The Numerical Calculation of Highway Slope Stability under the Influence of Rainfall

The slope deformation and instability caused by rainfall is the most common geological hazard in the highway slope landslide hazards. This paper used the finite element method to analyze the stability of slop in a variety of water-saturated conditions based on the strength reduction method, and to get the mechanism of rainfall weakening the strength of landslide. The results shows that the slope landslide in the fully saturated state would be instability when the surface was muddy geotechnical (thickness about 5 m), but it could remain stable when the saturated rate was under 80%. Under the action of rainfall, the maximum shear stress of potential slip plane in this kind of slopes was in the landslide’s lower edge which has obvious stress concentraten. Therefore, slope control measures should be strengthened to prevent the occurrence of the landslide hazard in the lot of long rainy season.

The Stability and Management of “Sandwich” Type Slopes in Extrusive Rock Area

Northern area of Hainan Island is located in the south of Leiqiong faulted zone; new tectonic movement and volcanic activity have intense since late tertiary. Cenozoic volcano in the region is developed, various types of extrusive rocks widely distributed which often directly cumulate on the Cenozoic sedimentary soil layers, then covered by more loose soil, form a soft - hard - soft “sandwich” type slope with a poor stability. Based on the study of this slope and simulate its stability, this paper proposed this kind of slope's destruction mechanism as well as the management method