scholarly journals Optimization Directions for Monitoring of Ground Freezing Process for Grzegorz Shaft Sinking

2021 ◽  
Author(s):  
Paweł Kamiński
Keyword(s):  
Rock Mass ◽  
Freezing Process ◽  
Mine Shaft ◽  
Freezing Method ◽  
Ground Freezing ◽  
Starting Point ◽  
Shaft Sinking ◽  
High Level ◽  
Geophysical Measurements

Grzegorz shaft is the first mine shaft sunk in 21st century in Silesian Coal Basin in USA of ground freezing method. Work carried out by Shaft Sinking Company (PBSz S.A.) is characterized by high level of innovativeness. Geophysical measurements were conducted to find directions of optimization of ground freezing process and its monitoring. Data gathered during research is a starting point for finding directions of optimization of particular fields during Grzegorz shaft sinking, as well as to be used in future similar ventures. Proposed solutions might have bring real improvements for safety and effectiveness of work and also for economic factors. Conducted tests and analysis aim at improvement of monitoring of shape, size and quality of frozen rock mass column in a safe and reliable manner.

scholarly journals In situ monitoring of frost heave pressure during cross passage construction using ground-freezing method

2016 ◽  
Vol 53 (3) ◽  
pp. 530-539 ◽  
Author(s):  
Lei Han ◽  
Guan-lin Ye ◽  
Yuan-hai Li ◽  
Xiao-he Xia ◽  
Jian-hua Wang
Keyword(s):  
Pressure Gauge ◽  
Earth Pressure ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Freezing Process ◽  
Groundwater Levels ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

The artificial ground-freezing method has the dual effect of ground reinforcement and waterproof sealing, and the frozen curtain can be designed flexibly. It is widely used in the construction of cross passages for shield tunnels in soft ground with high groundwater levels. However, due to the lack of in situ monitoring data, it remains difficult to determine the frost heave pressure acting upon a tunnel. In this study, based on the use of an anti-freezing pad-type earth pressure gauge, in situ monitoring was carried out to measure the frost heave pressure acting upon tunnel segments during the construction of cross passages for the Shanghai Yangtze River Tunnel. The monitoring results show that the earth pressure acting upon the tunnel could decrease dramatically during freezing, and this kind of decrease can take place suddenly and unpredictably, which can be illustrated using the finite element method. The maximum measured frost heave pressure during freezing and cross passage excavation was approximately 0.2 MPa, which was much smaller than the predicted value. Combining the distribution of temperature in the ground and construction countermeasures, the observed phenomena are mainly related to three factors: water migration during the freezing process, the tunnel–ground interaction, and the countermeasure of pressure release holes. The tunnel showed a horizontal extension–deformation, which was consistent with the releasing frost heave pressure acting upon it.

Improving the Efficiency of Artificial Ground Freezing in Urban Underground Construction by Using Solid Carbon Dioxide

2016 ◽  
Vol 843 ◽  
pp. 65-71
Author(s):  
Mikhail Shuplik ◽  
Petr Nikolaev
Keyword(s):  
Carbon Dioxide ◽  
Heat Dissipation ◽  
Experimental Investigations ◽  
Freezing Process ◽  
Construction Technology ◽  
Solid Carbon ◽  
Underground Structures ◽  
Solid Carbon Dioxide ◽  
Freezing Method ◽  
Ground Freezing

At the present time there are several basic methods of soils characteristics increase during the underground structures construction. Though, frequently the ground freezing method is the most efficient way. Modern Russian investigations show, that in case of small values of frozen grounds (less than 1000 m3) the cost of construction works significantly increase. In such conditions the relevant construction technology is a ground freezing method with the use of solid carbon dioxide, which nowadays is under development in the Mining College in National University of Science and Technology MIS&S.The present article shows the brief review of the main manufacturing schemes of the ground freezing, results of the new theories and experimental investigations, also the analysis of a commercial introduction experience of the ground freezing technology with the using of carbon dioxide.So far, the main difficulties during freezing process design were with the determination of a heat flow to the freezing pipe`s direction. It was not possible to predict the dynamic of ice wall formation and the discharge of carbon dioxide. According to the last investigations, we were succeed in determinating the change dependence of the heat dissipation, depending on the rock massive characteristics, granulometric composition of solid carbon dioxide and also its changing along the freezing pipe. That is why, now we may say that, the developing technology became not just a laboratory workout, but can already has a widespread adoption in praxis

The Assessment of Susceptibility on Drainage in an Aquifer on the Basis of Pumping Tests in a Lignite Mine / Ocena Podatności Ośrodka Wodonośnego Na Odwodnienie Na Podstawie Próbnych Pompowań W Kopalni Węgla Brunatnego

2015 ◽  
Vol 60 (1) ◽  
pp. 107-121
Author(s):  
Krzysztof Polak ◽  
Karolina Kaznowska-Opala ◽  
Katarzyna Pawlecka ◽  
Kazimierz Różkowski ◽  
Jerzy Klich
Keyword(s):  
Rock Mass ◽  
Drainage System ◽  
Resistance Coefficient ◽  
Mining Operations ◽  
Pumping Tests ◽  
Hydrogeological Parameters ◽  
Current State ◽  
Lignite Mine ◽  
Starting Point

Abstract Drainage of the rock mass is a key component affecting the safety of mining operations and is associated with the removal of the overburden, dumping and excavation of useful minerals. The primary method of drainage in lignite coal mines are bored wells. The efficiency of drainage of rock mass depends on their accurate positioning and quality of workmanship. The paper presents the current state of knowledge concerning the distribution of the components of drawdown (1) in pumping well (Walton, 1955; Bruin & Hudson, 1961; Kruseman & de Ridder, 1991; Avci, 1992; Atkinson, 1994; Helweg, 1994; Kawecki, 1995; Singh, 2002; Dufresne, 2011) and their dependence on the hydrogeological parameters of the drained aquifer (Fig. 2). The results of pumping tests conducted in drainage wells operating in lignite mines are also presented. The subject of analysis was the geohydraulic resistance coefficient B, describing the resistance of the aquifer under laminar flow. This coefficient also takes the hydrogeological parameters into account which determines the dynamics and range of influence of drainage (12, 13). The value of the parameter and its spatial variability can be used for planning, designing and evaluating the effectiveness of wells drainage In view of the results of the pumping tests, classification of aquifer susceptibility to drainage was proposed, which can be used to support decision-making in the scope of expansion of the drainage system, the necessary timing and dynamics of pumping water. The classification is preliminary and is the starting point for the development of methods to rationalize functioning costs of the drainage systems.

scholarly journals Application of Artificial Ground Freezing Technology in Modern Urban Underground Engineering

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yi Qi ◽  
Jinxun Zhang ◽  
Hao Yang ◽  
Yongwei Song
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Freezing Process ◽  
Physical Model Test ◽  
Group Effect ◽  
Underground Engineering ◽  
Sandy Gravel ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Based on typical water-rich sandy gravel strata in Beijing, in order to explore the application of the artificial ground freezing method (AGF) in urban large-scale underground engineering, the formation and development of freezing body were analyzed when multirow freezing pipes were working together, and the group effect exhibited during the freezing process was also revealed in this paper. On this basis, the basin-shaped freezing method (BFM) is put forward as an application of AGF used in underground engineering. BFM structure consists of two parts: the frozen curtain (basin wall) around the excavation scope and the horizontal frozen body (basin bottom) at the bottom of the station. Physical model test and numerical simulation were conducted to study temperature field expansion of BFM under two different conditions. The results show the following: (1) The group effect refers to the cooling effect of different freezing pipes influencing each other during freezing process. Under the condition of still water, the group effect expands the freezing area, and it shows the gradual development of freezing from back water surface to front water surface under seepage condition. (2) BFM can effectively play the role of water proofing, and although different parts of basin structure show different frozen order under different conditions, both basin wall and basin bottom can form an effective thickness during the freezing process.

Rapid Mechanized Shaft Sinking

2020 ◽  
pp. 22-29
Author(s):  
D.A. Igolka ◽  
F Otten
Keyword(s):  
Economic Performance ◽  
Critical Path ◽  
Underground Mines ◽  
Processing Plant ◽  
Mine Shaft ◽  
Freezing Method ◽  
Innovative Method ◽  
Geological Conditions ◽  
Shaft Sinking ◽  
The Republic

REDPATH DEILMANN GmbH from Germany has been sinking and lining two shafts and initial underground development since 2017 on the territory of the Republic of Belarus (Starobinskoe potassium salt deposit, Luban) by request of Slavkaliy LLC. Shaft sinking is one of the most complicated and time-consuming stages in renovation and construction of new underground mines. In the absolute majority of cases, shaft sinking and lining are at the critical path for implementation of such projects. Rapid rates of shaft construction ensure high technical and economic performance during the commissioning phase and earlier supply of end products to the market. The article introduces an innovative method of mechanized mine shaft sinking that provides rapid parallel sinking and lining of the mine shafts. Unique mechanized shaft boring roadheaders (SBR) manufactured by Herrenknecht are employed. Shaft sinking is done in complicate geotechnical and geological conditions intensified by a very low stability of the rocks using a dedicated rock freezing method. Modern materials are used for additional hydrosealing of the tubing liner. Workings in the near shaft insets are driven with roadheaders. A combination of all these solutions makes it possible to accelerate shaft sinking in a safe way without blasting operations and with high technical and economic performance both for the shaft sinking project and the overall construction of the mining and processing plant.

Citizen Experience Design for Digital Transformation

2021 ◽  
Author(s):  
Vanessa Colina Unda
Keyword(s):  
Case Studies ◽  
Digital Transformation ◽  
Experience Design ◽  
Human Centered Design ◽  
Starting Point ◽  
User Centric ◽  
High Level

How many times have you heard the term "human-centered design"? How about "human-centered technology"? These terms are often used interchangeably in conversations involving digital transformation. The purpose of this paper is to provide a path for policymakers to start considering user-centric design to better understand citizens characteristics, challenges, and needs. The guidelines and case studies presented here are meant to be timeless, high-level, and strategic. There is a focus on principles throughout the publication that can be used and adapted for any particular starting point. The paper also describes suggested metrics to measure and improve the quality of the citizen experience.

scholarly journals Numerical simulation of vertical shaft sinking using artificial ground freezing

2021 ◽  
Vol 266 ◽  
pp. 03008
Author(s):  
M.S. Zhelnin ◽  
A.A. Kostina ◽  
O.A. Plekhov ◽  
L.Y. Levin
Keyword(s):  
Numerical Simulation ◽  
Soil Freezing ◽  
Design Parameters ◽  
Freezing Process ◽  
Vertical Shaft ◽  
Ground Freezing ◽  
Shaft Sinking ◽  
Artificial Ground Freezing ◽  
Ice Content ◽  
Fully Coupled

Artificial ground freezing (AGF) is used worldwide for vertical shaft sinking in difficult hydrogeological conditions. The modern tendency is to determine the design parameters of the freezing technique based on numerical simulation. This work is devoted to the numerical simulation of the formation of an ice-soil wall in the soil stratum due to the AGF and shaft sinking under the protection of the wall. For this purpose, a fully coupled thermo-hydro-mechanical model of soil freezing has been developed on the basis of the theory of poromechanics. The developed model considers important features of the freezing process, such as the phase change, pore water migration due to cryogenic suction, frost heave, and consolidation of the soil. The results have shown that the model allows to predict the distribution of ice content, assess stress and strain in the ice-soil wall, and estimate displacement of the excavation wall.

scholarly journals Numerical simulation of cement grouting of saturated soil during a mine shaft sinking using the artificial ground freezing

2020 ◽  
Vol 28 ◽  
pp. 693-701
Author(s):  
M. Zhelnin ◽  
A. Kostina ◽  
O. Plekhov ◽  
L. Levin
Keyword(s):  
Numerical Simulation ◽  
Saturated Soil ◽  
Mine Shaft ◽  
Cement Grouting ◽  
Ground Freezing ◽  
Shaft Sinking ◽  
Artificial Ground Freezing

Heart Rate Recovery Changes during Competition Period in High-Level Basketball Players

2018 ◽  
Vol 1 (80) ◽  
Author(s):  
Audrius Gocentas ◽  
Anatoli Landõr ◽  
Aleksandras Kriščiūnas
Keyword(s):  
Heart Rate ◽  
Heart Rate Recovery ◽  
Team Sports ◽  
Basketball Players ◽  
Coeffi Cients ◽  
Competition Period ◽  
Monitoring Training ◽  
Intense Training ◽  
High Level

Research background and hypothesis. Replete schedule of competitions and intense training are features of contemporary team sports. Athletes, especially the most involved ones, may not have enough time to recover. As a consequence, aggregated fatigue can manifest in some undesirable form and affect athlete’s performance and health.Research aim. The aim of this study was to evaluate the changes in heart rate recovery (HRR) and investigate possible relations with sport-specifi c measures of effi cacy in professional basketball players during competition season.Research methods. Eight male high-level basketball players (mean ± SD, body mass, 97.3 ± 11.33 kg; height 2.02 ± 0.067 m, and age 23 ± 3.12 years) were investigated. The same basketball specifi c exercise was replicated several times from September till April during the practice sessions in order to assess the personal trends of HRR. Heart rate monitoring was performed using POLAR TEAM SYSTEM. Investigated athletes were ranked retrospectively according to the total amount of minutes played and the coeffi cients of effi cacy. Research results. There were signifi cant differences in the trends of HRR between the investigated players. The most effective players showed decreasing trends of HRR in all cases of ranking.Discussion and conclusions. Research fi ndings have shown that the quality of heart rate recovery differs between basketball players of the same team and could be associated with sport-specifi c effi cacy and competition playing time.Keywords: adaptation, autonomic control, monitoring training.

About Innovative Content of Subject-Oriented Pedagogical Education

2019 ◽  
Vol 28 (10) ◽  
pp. 106-117
Author(s):  
R. M. Asadullin
Keyword(s):  
Teacher Education ◽  
Teacher Training ◽  
Educational Process ◽  
Professional Activity ◽  
Subject Knowledge ◽  
Technological Structure ◽  
State Pedagogical ◽  
High Level ◽  
Competencies Development

The continuous modernization of the education system makes the problems of the quality of teacher training increasingly relevant. Moreover, the measures taken to improve the system of teacher education are largely confined to the introduction of new organizational and managerial mechanisms and practically do not affect the internal content and technological structure of the teacher training process.Modern pedagogical universities are constantly looking for innovative models of training teachers that will be able to solve non-standard social and professional tasks. However, recent studies in this area do not fully take into account the nature of pedagogical activity and conditions of its formation. Thus, the need arises for a special study of the processes and means of updating the content and technologies of teacher training in order to control the level of students’ professional competencies development, as required by educational and professional standards. This means the creation of a special educational system in a pedagogical university, which can provide a harmonious and synchronous mastering by future specialists of both subject knowledge and methods of pedagogical activity.The article provides a theoretical study aimed at identifying key patterns of designing a new content for teacher education, the basis of which is the formation of a future teacher as a subject of his own professional activity. The author describes the experience of using a subject-oriented model of education, implemented at Bashkir State Pedagogical University n.a. M. Akmulla. The effectiveness of this model is confirmed by the high level of students’ mastery of designing methods and constructing the educational process, as well as their positive experience in the implementation of educational activities.

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