scholarly journals ON THE POSSIBILITY OF ESTIMATING THE STABILITY OF SLOPES AND SLOPES ON THE BASIS OF THE SOLUTION OF THE MIXED PROBLEM OF THE ELASTICITY THEORY AND THEORY OF SOIL PLASTICITY

2020 ◽  
Vol 8 (1) ◽  
pp. 48-58
Author(s):  
Oksana Bogomolova ◽  
Andrej Zhidelev
Keyword(s):  
Mixed Problem ◽  
Pressure Coefficient ◽  
Experimental Studies ◽  
Stability Margin ◽  
Soil Mass ◽  
Breaking Load ◽  
Theory Of Elasticity ◽  
Stability Of Slopes ◽  
Analytical Construction ◽  
The Stability

the article briefly describes the physical model of the mixed problem of the theory of elasticity and the theory of plasticity of the soil, identifies the features of its formulation and solution; formulas are presented for calculating stresses inside plastic regions and expressions that allow one to determine their position, dimensions and shape in the case of an elastoplastic stress distribution in a soil mass. A comparison is made of the results of experimental studies of the fracture processes of slope models from equivalent materials under loading, obtained independently by other authors, with the results of the analytical construction of plastic strain regions for the conditions of the mixed problem. It was established that the constructed areas are in satisfactory agreement with the results obtained in laboratory studies and with the results of field observations. The areas of plastic deformations for slope models of equivalent materials under breaking load are determined. The results of calculations of the stability of real natural slopes are presented, which include the calculation of stability margin coefficients and the construction of plastic regions for various values ​​of the lateral pressure coefficient of soils. Stability calculations are performed and their results are presented for real soil massifs

scholarly journals ENSURING THE STABILITY OF INTERNAL DUMPS ACCORDING TO THE RESULTS OF PHYSICAL AND MECHANICAL PARAMETERS OF SOILS

2021 ◽  
pp. 38-45
Author(s):  
Stanislav Stovpnyk ◽  
Tetiana Kosenko
Keyword(s):  
Slope Angle ◽  
Physical And Mechanical Properties ◽  
Stability Margin ◽  
Geological Structure ◽  
Fine Grained ◽  
Lower Tier ◽  
Stability Of Slopes ◽  
The Stability ◽  
The Impact ◽  
Selective Formation

Purpose. The paper considers the issues of ensuring the stability of internal dumps consisting of soft rocks. This issue is relevant because the stability of quarry boards and dumps affects the safety of work in quarries. Methodology. When assessing the stability of slopes, the method of determining the minimum coefficient of stability, equal to the ratio of restraining forces to shear forces that arise in the slope array. Findings. The calculation and assessment of the stability of the slopes of the dumps are carried out on the example of Malyshevsky rutile-zircon-ilmenite deposit. The geological structure of the deposit overburden is represented by loess-like loams, red-brown clays, gray-green clays, fine-grained sands. To ensure the stability of internal dumps, the selective formation of dumps is proposed, which is presented in this paper in two ways. In the first variant, the dumping of Sarmatian gray-green clays into the lower part of the heap, which are weakly permeable and have low strength, is considered. In the second variant, a layer of Sarmatian sands is poured into the base of the dump. According to the normative value of the coefficient of stability margin, depending on the physical and mechanical properties of the rocks that make up the array, the optimal height and slope angle of the dump are determined. When assessing the stability of the slopes of the dump, the impact of groundwater and the possibility of location in the developed space of the tailings were also taken into account. Originality and Practical implications. Studies have shown that the most rational option is the formation of internal heaps with embedding in the base of the lower tier of the heap with a height of 40 m layer of Sarmatian sands; in the case of embedding in the lower part of the inner heaps of gray-green clays, it is advisable to form the lower tier of the heap with 2 sub-tiers up to 20 m high; the upper tier of the dump is recommended to be formed by one massif 26 m high. Besides, in the produced space of the quarry, the location of the tailings is possible in case of dumping Sarmatian sands into the base of the dump.

scholarly journals A limit equilibrium analysis of progressive failure in the stability of slopes

1978 ◽  
Vol 15 (1) ◽  
pp. 113-122 ◽  
Author(s):  
K. Tim Law ◽  
Peter Lumb
Keyword(s):  
Slip Surface ◽  
Progressive Failure ◽  
Limit Equilibrium ◽  
Friction Angle ◽  
Soil Mass ◽  
Local Failure ◽  
Equilibrium Analysis ◽  
Stability Of Slopes ◽  
The Stability ◽  
Definition Of

A limit equilibrium method of analysis is proposed for the study of progressive failure in slope stability under a long-term condition. Based on effective stresses, the formulation of the method is derived from consideration of force and moment equilibrium within the soil mass above a prospective slip surface. By dividing the soil mass into a number of vertical slices, recognition of local failure can be made. Once local failure takes place, post-peak strength is assumed to be operative. This then initiates a redistribution of interslice forces and leads to some further local failure. Thus realistic available strengths along the slip surface can be evaluated. This permits the definition of a final safety factor, which is expressed in terms of the actual available reserve of strength. The proposed method has been applied to three well documented case records and encouraging results have been obtained. Based on the assumption that post-peak strengths are given by a friction angle equal to the peak value and a zero cohesion, stability charts have been prepared for design purposes.

scholarly journals ACTIVITY TO PREVENT EMERGENCY SITUATIONS OF CASCADE TYPE OF SPREADING RELATED TO SOIL LANDSLIDE

2021 ◽  
pp. 52-57
Author(s):  
Nina Rashkevich ◽  
Volodymyr Koloskov ◽  
Igor Fedyuk
Keyword(s):  
Solid Waste ◽  
Experimental Research ◽  
Experimental Studies ◽  
Shear Load ◽  
Technological Equipment ◽  
Emergency Situations ◽  
Stability Of Slopes ◽  
Before And After ◽  
The Stability ◽  
Cascade Type

Landfills for solid waste with liquidation energy-intensive technological equipment, due to emergencies of the cascade type of distribution associated with the landslide of landfills, pose a man-made environmental hazard. Experimental studies to determine the effect of humidity, density, temperature of landfill soils on the stability of slopes on landslides have shown that with increasing humidity and temperature, the resistance of the array to displacement decreases. The lower the density, the greater the ability to penetrate and saturate with moisture, which creates additional shear load. According to the results of experimental research, a method of prevention of cascade-type emergencies related to landfill landslides at the landfill with liquid energy-intensive technological equipment has been developed to prevent the consequences of danger from escalating from site to higher levels of distribution. The method consists of measures "before" and "after" the fact of moving the landslide.

scholarly journals Performance Evaluation of Heading-and-Winning Machines in the Conditions of Potash Mines

2021 ◽  
Vol 11 (8) ◽  
pp. 3444
Author(s):  
Sergey A. Lavrenko ◽  
Dmitriy I. Shishlyannikov
Keyword(s):  
Energy Efficiency ◽  
Experimental Studies ◽  
Efficiency Coefficient ◽  
Mechanized Method ◽  
Methodological Approaches ◽  
The Stability ◽  
Technical Solutions ◽  
Potash Mine ◽  
Complex Indicators ◽  
Potassium Magnesium

The authors focus on the process of potash ore production by a mechanized method. They show that currently there are no approved procedures for assessing the performance of heading-and-winning machines operating in the conditions of potash mines. This causes difficulties in determining the field of application of heading-and-winning machines, complicates the search for implicit technical solutions for the modernisation of existing models of mining units, prohibits real-time monitoring of the stability of stope-based technological processes and makes it difficult to assess the performance of the services concerning mining enterprises. The work represents an aggregate assessment of the performance of heading-and-winning machines for potash mines by determining complex indicators describing the technological and technical levels of organising the work in stopes. Such indicators are the coefficients of productivity and energy efficiency, respectively. Experimental studies have been carried out in the conditions of the potash mine of the Verkhnekamskoye potassium-magnesium salt deposit to assess the performance of the latest and most productive Ural-20R heading-and-winning machines manufactured in Russia. Using the above methodological approaches, this paper shows that the unsatisfactory technological performance of the studied machine is due to the low productivity of the mine district transport. The average productivity coefficient was 0.29. At the same time, high values of the energy efficiency coefficient show that the productivity of the machine is on par with design conditions.

scholarly journals Stability-Guaranteed and High Terrain Adaptability Static Gait for Quadruped Robots

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4911
Author(s):  
Qian Hao ◽  
Zhaoba Wang ◽  
Junzheng Wang ◽  
Guangrong Chen
Keyword(s):  
Impedance Control ◽  
Stability Margin ◽  
Planning Method ◽  
Legged Robots ◽  
Gait Planning ◽  
Quadruped Locomotion ◽  
Quadruped Robots ◽  
Adjustment Strategy ◽  
Compliant Behavior ◽  
The Stability

Stability is a prerequisite for legged robots to execute tasks and traverse rough terrains. To guarantee the stability of quadruped locomotion and improve the terrain adaptability of quadruped robots, a stability-guaranteed and high terrain adaptability static gait for quadruped robots is addressed. Firstly, three chosen stability-guaranteed static gaits: intermittent gait 1&2 and coordinated gait are investigated. In addition, then the static gait: intermittent gait 1, which is with the biggest stability margin, is chosen to do a further research about quadruped robots walking on rough terrains. Secondly, a position/force based impedance control is employed to achieve a compliant behavior of quadruped robots on rough terrains. Thirdly, an exploratory gait planning method on uneven terrains with touch sensing and an attitude-position adjustment strategy with terrain estimation are proposed to improve the terrain adaptability of quadruped robots. Finally, the proposed methods are validated by simulations.

Study on the characteristics of secondary arc current of UHV high compensation degree TCSC line under the fine-tuning mode

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Baina He ◽  
Yadi Xie ◽  
Jingru Zhang ◽  
Nirmal-Kumar C. Nair ◽  
Xingmin He ◽  
...  
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Stability Margin ◽  
Transmission Capacity ◽  
Fine Tuning ◽  
Series Compensation ◽  
Arc Current ◽  
Compensation Device ◽  
The Stability ◽  
Recovery Voltage

Abstract In the transmission line, the series compensation device is often used to improve the transmission capacity. However, when the fixed series capacitor (FSC) is used in high compensation series compensation device, the stability margin cannot meet the requirements. Therefore, thyristor controlled series compensator (TCSC) is often installed in transmission lines to improve the transmission capacity of the line and the stability of the system. For cost considerations, the hybrid compensation mode of FSC and TCSC is often adopted. However, when a single-phase grounding fault occurs in a transmission line with increased series compensation degree, the unreasonable distribution of FSC and TCSC will lead to the excessive amplitude of secondary arc current, which is not conducive to rapid arc extinguishing. To solve this problem, this paper is based on 1000 kV Changzhi-Nanyang-Jingmen UHV series compensation transmission system, using PSCAD simulation program to established UHV series compensation simulation model, The variation law of secondary arc current and recovery voltage during operation in fine tuning mode after adding TCSC to UHV transmission line is analyzed, and the effect of increasing series compensation degree on secondary arc current and recovery voltage characteristics is studied. And analyze the secondary arc current and recovery voltage when using different FSC and TCSC series compensation degree schemes, and get the most reasonable series compensation configuration scheme. The results show that TCSC compensation is more beneficial to arc extinguishing under the same series compensation. Compared with several series compensation schemes, it is found that with the increase of the proportion of TCSC, the amplitude of secondary arc current and recovery voltage vary greatly. Considering various factors, the scheme that is more conducive to accelerating arc extinguishing is chosen.

scholarly journals Optimal profile for concave slopes under static and seismic conditions

2016 ◽  
Vol 53 (9) ◽  
pp. 1522-1532 ◽  
Author(s):  
Farshid Vahedifard ◽  
Shahriar Shahrokhabadi ◽  
Dov Leshchinsky
Keyword(s):  
Limit Equilibrium ◽  
Stable Configuration ◽  
Preliminary Evaluation ◽  
Construction Technology ◽  
Stability Of Slopes ◽  
Optimal Profile ◽  
Stabilized Soil ◽  
The Stability ◽  
Comparison Of The Results ◽  
The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

scholarly journals Extended-State-Observer-Based Super Twisting Control for Pneumatic Muscle Actuators

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 35
Author(s):  
Yu Cao ◽  
Zhongzheng Fu ◽  
Mengshi Zhang ◽  
Jian Huang
Keyword(s):  
Control Method ◽  
Experimental Studies ◽  
State Observer ◽  
Extended State Observer ◽  
Extended State ◽  
Pneumatic Muscle ◽  
System States ◽  
The Stability ◽  
Twisting Control ◽  
Muscle Actuators

This paper presents a tracking control method for pneumatic muscle actuators (PMAs). Considering that the PMA platform only feedbacks position, and the velocity and disturbances cannot be observed directly, we use the extended-state-observer (ESO) for simultaneously estimating the system states and disturbances by using measurable variables. Integrated with the ESO, a super twisting controller (STC) is design based on estimated states to realize the high-precision tracking. According to the Lyapunov theorem, the stability of the closed-loop system is ensured. Simulation and experimental studies are conducted, and the results show the convergence of the ESO and the effectiveness of the proposed method.

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