scholarly journals SEASONAL CHANGES IN THE VALUE OF THE RESISTANCE COEFFICIENT OF THE LANDSLEND

2020 ◽  
Vol 11 (3) ◽  
pp. 77-88
Author(s):  
O. A Bogomolova ◽  
A. V Zhidelev
Keyword(s):  
Stable State ◽  
Maximum Level ◽  
Resistance Coefficient ◽  
Strength Properties ◽  
Safety Factors ◽  
River Bank ◽  
Sliding Surfaces ◽  
Additional Stability ◽  
The Stability ◽  
State Registration

The results of calculating the stability of a landslide-prone slope located on the river bank are presented. Additional stability studies were carried out due to the fact that, according to the results of slope calculations using various “compartments” methods, based on the construction of circular cylindrical sliding surfaces, the slope is in a stable state (tables are given containing the numerical values of the safety factors). However, in the spring-autumn period, local landslides occur on the slope. Therefore, new calculations of slope stability were carried out using a method based on the analysis of the stress state of the soil massif, which allows one to take into account the "weighing" effect of groundwater when it rises and the decrease in the strength properties of the constituent soils when they are soaked. This method is formalized in a computer program developed with the participation of one of the authors; the program has a certificate of state registration. Calculations have established that an increase in the level of groundwater to the maximum possible value reduces the values of the safety factors along the considered sliding lines by 5.9-21 %. It is shown that if the numerical values of the safety factors obtained by the methods of circular cylindrical sliding surfaces are reduced by 21 %, then some of their values will be very close to unity or even less, which resolves the above contradiction. When calculating the stability of landslide-prone soil masses, in which seasonal fluctuations of groundwater are possible, one should take into account the "weighing" effect of groundwater at the maximum level of their rise, a decrease in the physical and mechanical (strength) characteristics of soils due to their soaking and, preferably, the destabilizing effect of hydraulic heads.

New approaches to the assessment of stability of rock rock arrays

2020 ◽  
pp. 68-77
Author(s):  
A. V. Zubkov ◽  
S. V. Sentyabov
Keyword(s):  
Rock Mass ◽  
Stable State ◽  
Strength Properties ◽  
State Standards ◽  
Mining Operations ◽  
Compressive Stresses ◽  
Rock Formations ◽  
Third Stage ◽  
The Stability ◽  
Definition Of

When summarizing the results obtained on the stability of rock masses a discrepancy was found between the parameters of the strength properties of rock formations, determined according to existing methods and state standards, to their values under natural conditions. As a result of the studies, the degree of geomechanical knowledge of the rock mass of the Gaisky underground mine is significantly increased. Based on the numerical simulation of the stress-strain state of the ore and rock mass, the rationale for the optimal mining of reserves at a depth of -830 / -1390 m was substantiated. The main compressive stresses of the Gaisky deposit act in the sub-latitudinal direction along the axis of the chambers, creating stresses exceeding 100 MPa on their outcrops. If the compressive strength of the massif is up to 100 MPa, found by known methods, ore masses of the third stage (pillars) below the -910 m horizon should be destroyed. In assessing the stability of pillars (chamber walls) in the last 3 years, in some cases, disagreement arose. The calculated stresses exceed the maximum allowable ones, but the pillars (chamber walls) remain stable. It justifies the correction of the obtained values of the ultimate strength of rocks with correction factors and the introduction of the definition of reduced strength (227 MPa), in which the roof, walls of the chambers and pillars are in a stable state. As a result of the study, the obtained values of the stress state of the rock mass and its strength characteristics more realistically reflect the predicted destruction or stability of the rock mass at the mine. The performed studies contribute to a more justified adjustment of mining technology parameters while ensuring the safety of mining operations.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

scholarly journals THE INFLUENCE OF THE STORAGE CONDITIONS OF RAW MATERIALS ON THE PRESERVATION OF THE PROPERTIES OF THE FUR SEMI-FINISHED PRODUCT

2021 ◽  
Vol 53 (3) ◽  
pp. 52-58
Author(s):  
Natalya P. Bodryakova
Keyword(s):  
Elevated Temperature ◽  
Relative Humidity ◽  
Raw Materials ◽  
Storage Conditions ◽  
Strength Properties ◽  
Biological Factor ◽  
Point Scale ◽  
Complex Characteristic ◽  
Characteristic Features ◽  
The Stability

This article deals with the problem of preserving the properties of a semi-finished fur product under the influence of a biological factor during the storage of raw materials. The characteristic features of the biodegradation of untreated rabbit skins during storage at elevated temperature and relative humidity are identified and described. A complex characteristic of a semi-finished fur product developed from raw materials of various degrees of microbiological spoilage is given. The author offers a point scale of assessment dynamics of the processes of destruction of fur raw materials and a point assessment of the organoleptic indicators of the semi-finished product was developed. As a result of comprehensive studies, it was found that the degree of damage to the fur raw materials being processed affects the decrease in the stability of the structure and strength properties of the finished semi-finished product.

scholarly journals Soil-Root System Withholding Strength for River Bank Stability

2016 ◽  
Vol 77 (1) ◽  
Author(s):  
IR. PROF. DR RUSLAN HASSAN HASSAN ◽  
Ding Ibau
Keyword(s):  
Relative Strength ◽  
Shear Stresses ◽  
Strength Increase ◽  
Maximum Displacement ◽  
River Bank ◽  
Slope Stabilisation ◽  
Shearing Resistance ◽  
The Stability ◽  
Direct Shear Apparatus ◽  
Riverbank Restoration

The ability of vegetation to stabilise soils is frequently employed in slope stabilisation projects including riverbank restoration activity. Soil block samples permeated with roots of Bermuda Grass commonly used for remediation and riverbank restoration were tested in a direct shear apparatus. Shear stress results of rooted soils were compared with results of un-vegetated soil bloc—s with similar soil types. The increase of shear strength was determined by comparing shear stresses at speciic horizontal displacements. The relative strength increase at the same displacement was 27.3 kPa compared to 19.1 kPa for un-vegetated soil at a displacement of 13.3cm (Location 3). The relative strength increase at the same displacement of 13.3cm was 43.5% for Location 1 and 42.4% for Location 2. The shear stresses in most of the blocks with roots were still increasing at the end of the test (maximum displacement of about 15cm). These conservative root biomass values and the shearing resistance obtained can be used in the assessment of the stability of the existing vegetated slopes and in the design of vegetated riverbanks.

scholarly journals Review on Lateral Stability of Piled Riverine Structures in the Estuaries of Sarawak

2018 ◽  
Vol 7 (3.18) ◽  
pp. 21
Author(s):  
Lee Lin Jye ◽  
Shenbaga R. Kaniraj ◽  
Siti Noor Linda bt Taib ◽  
Fauzan Bin Sahdi
Keyword(s):  
Soft Soil ◽  
Natural State ◽  
Soil Conditions ◽  
Silty Clay ◽  
River Bank ◽  
Soil Movement ◽  
Geotechnical Problem ◽  
Construction Activity ◽  
Lateral Soil Movement ◽  
The Stability

Soft soil conditions with very soft and deep silty clay have constantly endangered the stability of the riverine and estuarine structures in Sarawak. There have been many failures of jetties, wharves and bridges in Sarawak. In many cases of failures, the piles were not designed to resist the lateral movement, unless they were included to stabilize unstable slopes or potential landslides. This practice may be due to reasons such as erroneously judging the river bank as stable in slope stability analysis or simply due to the inexperience of designers. Also, when the river bank approaches the limiting stability in its natural state any construction activity on the river bank could result in lateral soil movement. This paper highlights this important geotechnical problem in Sarawak. Then it presents the details of a few failures of estuarine structures. A review of situations causing lateral loading of piles is then presented. The results of the in-soil and in-pile displacement measurements are shown in this paper and it is found that the computation made to compare between field and 3D modeling is agreeable.  

scholarly journals Shrinkage and Strength Properties of Coal Gangue Ceramsite Lightweight Aggregate Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yunsen Wang ◽  
Jingping Qiu ◽  
Chao Zeng
Keyword(s):  
Waste Treatment ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Coal Gangue ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Concrete Shrinkage ◽  
Strength Tests ◽  
The Stability

It is a promising and effective method for waste treatment by using coal gangue to make lightweight aggregate concrete. However, lightweight aggregate concrete with low-density coal gangue ceramsite is prone to cracking during volume shrinkage, which limits its application in the construction industry. In an attempt to resolve the problem of cracking in shrinkage, this study investigated the effect of prewetting time and shrinkage reducing agents on shrinkage volume and concrete strength through a series of concrete shrinkage and strength tests. The experimental results show that shrinkage volume reduced at a prewetting time of 12 hrs or with a 2% addition of D-230 polyether amine reductant. With the optimal conditions of 12 hrs prewetting time and 2% addition of the reductant, the concrete shrinkage volume significantly decreased with a negligible impact on its strength. Appropriate amount of shrinkage reducing agent and adjustment of prewetting time of coal gangue ceramsite are necessary to reduce the shrinkage rate and improve the stability of the specimen. This is of great significance to wide application of lightweight aggregate concrete with coal gangue ceramsite.

Comparison of Piezoelectric Structural Damping Based on Velocity Controlled Switching and Pulse Width Modulation Switching Circuits

2012 ◽  
Author(s):  
Dejan Vasic ◽  
Yuan-Ping Liu ◽  
François Costa
Keyword(s):  
Pulse Width Modulation ◽  
Stable State ◽  
Piezoelectric Element ◽  
Voltage Source ◽  
Vibration Velocity ◽  
Constant Voltage ◽  
Vibration Displacement ◽  
Controlled Switching ◽  
The Stability ◽  
Piezoelectric Voltage

Two novel piezoelectric damping techniques (VSD and PWMD) are compared in this paper to the traditional resonant shunt damping technique and SSDV technique. In VSD, the switching shunt circuit turns ON or OFF according to the polarity of the vibration velocity of the host structure to shift the piezoelectric voltage phase. An external voltage source is connected to enlarge the voltage amplitude across the piezoelectric element and to optimize the dissipated power. The PWM shunt technique not only can decrease the audible noises more efficiently but also ensure the stability of the control system with a constant voltage source. The theoretical and the experimental results show that the piezoelectric voltage can be adaptive to the vibration displacement by the pulse widths variation, so the PWMD can stay in stable state with a constant voltage source and can still provide a very good performance.

Chemical repair of protein carbon-centred radicals: long-distance dynamic factors

2016 ◽  
Vol 94 (12) ◽  
pp. 1119-1126 ◽  
Author(s):  
Romina Castañeda-Arriaga ◽  
Adrián Domínguez-Castro ◽  
JinGyu Lee ◽  
J. Raul Alvarez-Idaboy ◽  
Nelaine Mora-Diez
Keyword(s):  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Alpha Helix ◽  
Diffusion Control ◽  
Long Distance ◽  
Dihydrolipoic Acid ◽  
Dynamic Factors ◽  
Additional Stability ◽  
The Stability ◽  
Protein Models

The thermodynamic and kinetic study of the repair reactions of three damaged aliphatic amino acids (alanine, valine, and leucine) with dihydrolipoic acid (DHLA) in a polar and a nonpolar solvent is presented in this work. Two simplified protein models were explored in the most common conformations (alpha helix and beta sheet). Calculations are performed at the M06-2X-SMD/6-31++G(d,p) level of theory. DHLA has shown to be an excellent antioxidant repair agent through hydrogen-transfer reaction involving the thiol groups, with rate constants close to diffusion control in most cases. The stability of the initial protein radical is not the most important factor determining the rate of the repair reaction because stabilizing intermolecular interactions involving the protein and the antioxidant can provide additional stability to some transition states accelerating the repair of sites that would otherwise not be so quickly repaired.

scholarly journals Relationship between river bank stability and hydrological processes using in situ measurement data

2019 ◽  
Vol 62 (1) ◽  
pp. 83-99 ◽  
Author(s):  
Gyula Mentes
Keyword(s):  
Measurement Data ◽  
Early Warning Systems ◽  
Bank Stability ◽  
River Bank ◽  
River Danube ◽  
Water Level Variations ◽  
Stable Part ◽  
The Stability ◽  
High Bank ◽  
River Banks

Many river banks throughout the world are prone to landslides; therefore, serious efforts are made to develop landslide early warning systems. This study presents a method by which the stability changes of the river banks can be continuously monitored; necessary measures can be taken in time to reduce the damage. The method was tested in Dunaszekcső (Hungary), where the high loess bank of the River Danube has been intensively moving since 2007. The tilts of the high bank were measured by two borehole tiltmeters. The connection between tilt values and the river- and groundwater-level variations was investigated by multivariable and moving window regression analyses on the basis of a 6-year-long observation from 2011 to 2016. The results show that increasing regression coefficients mean decreasing stability of the high river bank, so the developed method can be used for continuous supervision of the high bank stability. The method is also suitable for studying the causes of motion processes. Investigations showed clearly that the effect of groundwater table variations is two orders of magnitude higher than the water-level variations of the River Danube. In addition to the erosion of the river, various small tilts of the stable and unstable parts also contribute to the arising of new cracks in the stable part, decreasing its width.

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