scholarly journals Empirical regularities investigation of rock mass discharge by explosion on the free surface of a pit bench

2021 ◽  
Vol 249 ◽  
pp. 334-341
Author(s):  
Igor Alenichev ◽  
Ruslan Rakhmanov
Keyword(s):  
Rock Mass ◽  
Slope Angle ◽  
Rock Breaking ◽  
Key Factors ◽  
Technological Parameters ◽  
Factors Affecting ◽  
Geological Conditions ◽  
Empirical Regularities ◽  
Main Discharge ◽  
Mass Discharge

Minimizing the discharge of blasted rock mass into the developed space of the pit is a very relevant area for study, as it allows to increase the processability of work and reduce the cost of mining. The article presents the results of experimental industrial explosions, during which the study of this issue was conducted. The main purpose of the work was to establish the key factors affecting the volume of rock mass discharge to the pit haulage berm. During the analysis of the world experience of research on this topic, the key factors affecting the formation of collapse and discharge – natural and technological – are identified. The method of conducting experiments and collecting data for analyzing the influence of technological parameters of location, charging and initiation of wells on the volume of rock mass discharge is described. It is established that the main discharge to the pit haulage berm is formed by the volume of rock mass limited by the prism of the slope angle. With a sufficient rock mass displacement from the edge of the bench crest towards the center of the block, only the wells of the 1st and 2nd rows participate in the discharge formation. Empirical dependences of the total volume of rock mass discharge on the length of the block along the bench crest, the specific consumption of explosives, the size of a rock piece P50 and the rate of rock breaking are obtained. The obtained results can be used to design the parameters of the drilling and blasting operations (DBO), as well as to predict and evaluate the possible consequences of a mass explosion in similar mining and geological conditions.

scholarly journals Key Factors Affecting the Deformation and Failure of Surrounding Rock Masses in Large-Scale Underground Powerhouses

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Affecting Factors ◽  
Key Factors ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Factors Affecting ◽  
Geological Conditions

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.

scholarly journals Study of the Conditions for Construction of the Haulage Berm in the Deposit Ledger-Wall

2019 ◽  
Vol 105 ◽  
pp. 01034
Author(s):  
Svetlana Bakhaeva ◽  
Elena Chernykh
Keyword(s):  
Slope Angle ◽  
Open Pit ◽  
Factors Affecting ◽  
The Road ◽  
Road Base ◽  
Single Side ◽  
Geological Conditions ◽  
Shipping Cost ◽  
Shear Characteristics ◽  
Spoil Bank

To reduce transportation distance and shipping cost for rock haulage with a single-side development system, it is relevant to build roads on the spoil bank of the open-pit. The article reviews factors affecting stability of the spoil bank and the most common types of deformation. The backward calculation method for obtaining resistance to shear characteristics of the base rocks in contact with a road embankment has been described. Schemes for road constructions on the spoil bank of the open-pit have been considered. Mining and geometric simulation of the road base has been built. Zoning of the road base as per slope angle of the underlying rock and parameters of the haulage berm allow tracing rapidly axis of the technological and engineering roads for actual engineering and geological conditions. Besides, measures to reduce risk factors of landslides during construction of the haulage berm at deposit ledger-wall have been considered.

Numerical Simulation of the Rock Fragmentation Process Induced by TBM Cutters

2012 ◽  
Vol 249-250 ◽  
pp. 1069-1072 ◽  
Author(s):  
Gang Li ◽  
Bo Wang ◽  
Ya Dong Chen ◽  
Wan Shan Wang
Keyword(s):  
Rock Mass ◽  
Rock Breaking ◽  
Rock Fragmentation ◽  
Fragmentation Process ◽  
Disc Cutter ◽  
Material Strength ◽  
Joint Spacing ◽  
Geological Conditions ◽  
Breaking Mechanism ◽  
Cutter Spacing

The rock fragmentation process is the interaction process between TBM and rock mass, which is affected by TBM specifications, such as thrust force, cutter tip width and profile, cutter spacing, RPM, and torque, and rock mass properties mainly including rock material strength, rock brittleness, joint spacing and orientation. In this study, based on the systematic study of the existed rock constitutive model achievements and introduction of rock breaking mechanism, main failure mode of rock in the breaking process of disc cutter is added and revised in order to meet the actual situation. The method of establishing numerical model of disc cutter breaking process is introduced. After the dynamic simulation, we can obtain that geotechnical interface disturbance insulted by disc cutter. Based on plenty of experiments, it confirms reliability of numerical methods and provides a method to study cutting performance for different geological conditions.

scholarly journals Analyzing mechanics of rock breaking under conditions of hydromechanical drilling

2021 ◽  
Vol 15 (3) ◽  
pp. 122-129
Author(s):  
Andrii Ihnatov
Keyword(s):  
Rock Mass ◽  
Physical Simulation ◽  
Breaking Load ◽  
Rock Breaking ◽  
Next Generation ◽  
Technological Parameters ◽  
Well Drilling ◽  
Dynamic Component ◽  
Stable Mode ◽  
Load Rate

Purpose is to substantiate design factors and technological parameters of next-generation facilities of hydromechanical drilling basing upon the determined features of interaction between breaking pellets and rock mass. Methods. The studies of directionality features and bottomhole processes for rock mass breaking have been carried out using the current analytical methods and laboratory experiments. Among other things, certain mathematical and physical simulation techniques, methods of theoretical processing and interpretation of the research results under SolidWorks, Statgraphics, and Маthсаd environments, and a number of relevant instruments and materials have been applied. Following their technological sequence, the well bottomhole rock-breaking processes were simulated using a special laboratory stand equipped with a control-and-measuring unit (inclusive of a flowmeter, manometer, tachometer, and coordinate spacer among other things). Findings. Application perspectiveness of the combined techniques for rock breaking has been proved. Structural designs of the next-generation facilities for well drilling have been proposed. The pellet-impact drilling features have been analyzed from the viewpoint of its significant dynamic component during the rock mass breaking. Nature of the effect of breaking load rate on the results of bottomhole deformation processes has been identified. Efficiency of the proposed scheme to improve pellet-impact drilling based upon maximum use of a well bottomhole deformed by pellets has been proved. Measures to increase technical and technological indicators of pellet drilling have been considered. Requirements for the conditions stabilizing operation of a collar of the pellet-impact device have been outlined. Further research tendencies have been specified. Originality. It has been determined that compliance with specific geometrical and hydromechanical ratios, corresponding to the stable mode of a well sinking, is the factor required for reliable operation of hydromechanical drilling facilities. Practical implications. The results of stand-based tests as well as analytical studies may become the foundations to develop efficient engineering decision for hydromechanical well drilling with high technical and economic indicators. The data, concerning bottomhole rock breaking processes, are the basic ones to work out rational standard parameters of well sinking processes.

Numerical Simulation of Rock Fragmentation Process for TBM Cutters Based on Three-Dimensional Dynamic Fracturing Method

2012 ◽  
Vol 472-475 ◽  
pp. 2033-2036
Author(s):  
Gang Li ◽  
Li Da Zhu ◽  
Jian Yu Yang ◽  
Wan Shan Wang
Keyword(s):  
Rock Mass ◽  
Three Dimensional ◽  
Element Model ◽  
Rock Breaking ◽  
Disc Cutter ◽  
Material Strength ◽  
Rock Breakage ◽  
Joint Spacing ◽  
Geological Conditions ◽  
Cutter Spacing

The rock breakage process is the interaction process between TBM and rock mass, which is affected by TBM specifications, such as thrust force, cutter tip width and profile, cutter spacing, RPM, and torque, and rock mass properties mainly including rock material strength, rock brittleness, joint spacing and orientation. In this study, based on the systematic study of the existed rock constitutive model achievements and introduction of rock breaking mechanism, main failure mode of rock in the breaking process of disc cutter is added and revised in order to meet the actual situation. The method of establishing finite element model of disc cutter breaking process using ANSYS AUTODYN-3D software is introduced. After the dynamic simulation, we can obtain that geotechnical interface disturbance insulted by disc cutter. Based on plenty of experiments, it confirms reliability of numerical methods and provides a method to study cutting performance for different geological conditions.

Study on Parameters of Support for Control of Roof Fall and Rib Spalling in Large Fully Mechanized Top Coal Caving End Face

2012 ◽  
Vol 616-618 ◽  
pp. 421-425 ◽  
Author(s):  
Fu Lian He ◽  
Xiao Ming Wang ◽  
De Quan Zhang ◽  
Shang Sen He
Keyword(s):  
Numerical Simulation ◽  
Regression Analysis ◽  
Rock Mass ◽  
Mechanical Model ◽  
Key Factors ◽  
Factors Affecting ◽  
Roof Fall ◽  
Effect Of Support

Key factors affecting the control of roof fall and rib spalling are identified relying on the statistics for characteristics of roof fall and rib spalling distribution, and the regression analysis of the relationships of roof fall and rib spalling to support parameters by measuring actual ground pressures. The effect of support in controlling roof fall and rib spalling is analyzed by setting up a caving arch mechanical model of cataclastic coal and rock mass on fully mechanized caving face, and the key parameters of support are also determined using numerical simulation.

EVALUATION OF FINANCIAL SECURITY OF THE REPUBLIC OF CRIMEA

2020 ◽  
pp. 56-67
Author(s):  
Elena Evgenevna Mashyanova ◽  
Elena Aleksandrovna Smirnova
Keyword(s):  
Financial Markets ◽  
Negative Impact ◽  
Gradual Increase ◽  
Financial System ◽  
Financial Security ◽  
Key Factors ◽  
Factors Affecting ◽  
External Threats ◽  
The Republic ◽  
Global Financial System

In modern conditions of development, financial security is an integral part of the overall security of the region and is formed on the basis of the functioning of the financial system. The complication of relationships between key segments of international financial markets, as well as the limited ability to accurately predict future trends in the development of the global financial system, lead to a gradual increase in the risks that accompany the activities of economic entities, and an increase in the number and scale of internal and external threats that have a negative impact on the financial security of the state. This formulation of the issue requires generalization of approaches to determining the financial security of the region in order to further formalize this issue and determine the key factors affecting it. The article considers the types of financial security, as well as certain areas of ensuring the financial security of the region and their priority. In work the assessment of the level of socio-economic development of the region with a view to ensuring financial security on the basis of which offers the main activities and priority areas of implementation of the investment policy that will ensure financial security of the Republic of Crimea.

scholarly journals Comparison of the sensitivity of Western blotting between PVDF and NC membranes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufang Xiang ◽  
Yuanyuan Zheng ◽  
Shaobo Liu ◽  
Gang Liu ◽  
Zhi Li ◽  
...  
Keyword(s):  
Western Blotting ◽  
Polyvinylidene Fluoride ◽  
Staining Intensity ◽  
Detection Sensitivity ◽  
Key Factors ◽  
Post Translational Modifications ◽  
Factors Affecting ◽  
Molecular Weights ◽  
Direct Blue ◽  
The Relationship

AbstractWestern blotting (WB) is one of the most widely used techniques to identify proteins as well as post translational modifications of proteins. The selection of electroblotted membrane is one of the key factors affecting the detection sensitivity of the protein which is transferred from gel to membrane in WB. The most common used membranes are polyvinylidene fluoride (PVDF) and nitrocellulose (NC) membranes. Which membrane of these two is more suitable for WB has not been reported so far. Here, by incubating proteins which were transferred to PVDF or NC membranes with a series of antibodies and different types of lectins, we investigated the relationship between the binding ability of these two membranes to proteins or glycoproteins and the molecular weight of the target protein. The antibody re-probed ability of the two membranes was also explored. Moreover, we verified the above results by directly incubating proteins having different molecular weights onto PVDF or NC membranes. Bound proteins were stained with direct blue-71, and the staining intensity was quantitated by scanning and densitometry.

scholarly journals The Effects of Mobility as a Service and Autonomous Vehicles on People’s Willingness to Own a Car in the Future

2021 ◽  
Vol 13 (4) ◽  
pp. 1962
Author(s):  
Timo Liljamo ◽  
Heikki Liimatainen ◽  
Markus Pöllänen ◽  
Riku Viri
Keyword(s):  
Public Transport ◽  
Autonomous Vehicles ◽  
Travel Behaviour ◽  
Car Ownership ◽  
Key Factors ◽  
Sustainable Mobility ◽  
Factors Affecting ◽  
Mobility Service ◽  
The Future ◽  
Mobility Behaviour

Car ownership is one of the key factors affecting travel behaviour and thus also essential in terms of sustainable mobility. This study examines car ownership and how people’s willingness to own a car may change in the future, when considering the effects of public transport, Mobility as a Service (MaaS) and automated vehicles (AVs). Results of two citizen surveys conducted with representative samples (NAV-survey = 2036; NMaaS-survey = 1176) of Finns aged 18–64 are presented. The results show that 39% of respondents would not want or need to own a car if public transport connections were good enough, 58% if the described mobility service was available and 65% if all vehicles in traffic were automated. Hence, car ownership can decrease as a result of the implementation of AVs and MaaS, and higher public transport quality of service. Current mobility behaviour has a strong correlation to car ownership, as respondents who use public transport frequently feel less of a will or need to own a car than others. Generally, women and younger people feel less of a will or need to own a car, but factors such as educational level and residential location seem to have a relatively low effect.

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