Mechanism of deformation in rock mass surrounding intersection of mine shaft and salt bed

2021 ◽  
pp. 21-26
Author(s):  
V. P. Marysyuk ◽  
G. V. Sabyanin ◽  
A. A. Andreev ◽  
M. A. Vilner
Keyword(s):  
Rock Mass ◽  
Rock Salt ◽  
Observation Station ◽  
Mine Shaft ◽  
Deformation Stages ◽  
Rock Interface ◽  
Mechanical Linkage ◽  
Shaft Lining ◽  
Materials Used ◽  
Enclosing Rocks

A bed of rock salt in Komsomolsky Mine occurs in sedimentary strata enclosing cage and skip shafts. When water enters rock salt via underground excavations, boreholes and fractures, rock salt can dissolve and wash out, and voids appear in rock mass. Voids at the lining and rock interface should be eliminated so that never re-appear or grow during shaft operation. Materials used to eliminate voids should ensure stable mechanical linkage both with enclosing rocks and lining. Assessment and analysis of geomechanical processes induced by leaching need monitoring of deformations in a shaft. To this effect, one of the simplest and most informative methods is arrangement of an observation station directly in the shaft lining to measure varying distances between check points. The article briefly describes activities aimed to eliminate voids using different composition grouts. From the analysis of monitoring data, the deformation mechanism is described, and the interaction between different deformation stages and grouting steps is determined. The authors appreciate participations of experts M. P. Sergunin, I. A. Shishkina, A. K. Ustinov, V. V. Tsatskin, V. S. Orlov.

Geomechanical aspects of formation of natural stresses in a concrete mount of a shaft shaft

2020 ◽  
pp. 199-207
Author(s):  
S. V. Sentyabov
Keyword(s):  
Rock Mass ◽  
Analytical Methods ◽  
Structural Parameters ◽  
Strength Properties ◽  
Mine Shaft ◽  
The Earth ◽  
Shaft Lining ◽  
Time Variables ◽  
Average Size ◽  
Structural Blocks

In the presented studies, the laws of the formation of natural stresses in the rock mass are confirmed, which are the sum of gravitational, static tectonic and variable components that have a variable value as a result of uniform periodic volume expansion and contraction of the Earth. The problem of trunk stability is due to the need to solve problems to determine the level of stress-strain state and strength properties in concrete supports. The stress parameters in the lining of the shafts and the monitoring of their changes are determined using a new method for measuring unloading strains. When comparing the stresses obtained experimentally by analytical methods in the concrete support of mine shafts from 2013 to 2019 at experimental test sites in the support having the lengths of bases of 1600 and 70 mm, provided that the number of geoblock ranks at this base is two, a connection with the results of measurements in an array of rocks based on 50 m with an average size of structural blocks of 0.5 m and an investment coefficient of l = 5, which corresponds to three ranks of geoblocks. In practice, it is proposed to use the main identified provisions, namely: the stress state of the mine shaft lining, which is formed as a function of their structural parameters, the full tensor of gravitational tectonic stresses acting in the rock mass at the time of the start of research and time variables, which are determined by natural and analytical methods.

scholarly journals A New Method of Regulation of Loads Acting on the Shaft Lining in Sections Located in the Salt Rock Mass

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 42
Author(s):  
Paweł Kamiński
Keyword(s):  
Porous Medium ◽  
Rock Mass ◽  
Rheological Properties ◽  
Rock Salt ◽  
Contact Layer ◽  
Special Device ◽  
Test Results ◽  
Salt Rock ◽  
Rock Creep ◽  
Shaft Lining

Rock salt is characterized by specific geomechanical and rheological properties. Layers of rock salt at depths of over 900 m cause problems with shaft lining deformation. Methods of shaft lining protection used to date (e.g., in the Sieroszowice mine) have not been effective enough. The research presents a patented and copyright protected concept of a shaft lining construction that can be used in rock masses with strong rheological properties and susceptibility to leaching. A high value of convergence in salt rock mass is a reason for serious problems with shaft lining stability. Numerous trials have been done to provide appropriate shaft lining for salt layers, especially to ensure proper geometry of shaft members and conveyance guidance. In the new shaft lining concept, the excessive rock creep into the outbreak inside the shaft diameter is removed by local and controlled leaching of the shaft cheeks by means of fresh water through a porous medium at the contact layer behind the watertight tubing lining. The article presents the methodology of performing tests on a special device and the test results.

scholarly journals Microgravity Survey to Detect Voids and Loosening Zones in the Vicinity of the Mine Shaft

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3021
Author(s):  
Slawomir Porzucek ◽  
Monika Loj
Keyword(s):  
Rock Mass ◽  
Density Distribution ◽  
Geophysical Methods ◽  
Gravity Anomalies ◽  
Vertical Profiles ◽  
Mine Shaft ◽  
Mining Areas ◽  
Shaft Lining ◽  
Under Construction ◽  
Density Zone

In mining and post-mining areas, the assessment of the risks to the surface and its infrastructure from the opening or closed mine is of the utmost importance; particular attention should be paid to mine shafts. The risks include the occurrence of undetected voids or loosening zones in the rock mass. Their detection makes it possible to prevent their impact on a mine shaft and surface infrastructure. Geophysical methods, and in particular, a microgravity method lend themselves for the detection of changes in the distribution of masses (i.e., the density) due to voids and loosening zones. The paper presents the results of surface microgravity surveys in the vicinity of three mine shafts: under construction, working, and a liquidated one. Based on the gravity anomalies, the density distribution of the rock mass for all three cases was recognized. The properties of the anomalies allowed to determine which of the identified decreased density zones may pose a threat to the surface infrastructure or a mine shaft. The microgravity survey made inside the working mining shaft provided information on the density of rocks outside the shaft lining, regardless of the type of lining. No significant decrease of density was found, which means that there are no larger voids outside the shaft lining. Nevertheless, at a depth of 42 m in running sands layer, the decreasing density zone was located, which should be controlled. Additionally, measurements in two vertical profiles gave the possibility of directional tracking of density changes outside shaft lining. Such changes were observed on three boundaries of geological layers, with two of them being on the boundary of gypsum and other rocks.

scholarly journals Mechanism of Fracturing in Shaft Lining Caused by High-Pressure Pore Water in Stable Rock Strata

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jihuan Han ◽  
Jiuqun Zou ◽  
Weihao Yang ◽  
Chenchen Hu
Keyword(s):  
High Pressure ◽  
Rock Mass ◽  
Pore Water ◽  
Expansion Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Shaft Lining ◽  
Rock Strata ◽  
Expansion Effect

With the increase in shaft depth, the problem of cracks and leakage in single-layer concrete lining in porous water-rich stable rock strata has become increasingly clear, in which case the mechanism of fracturing in shaft lining remains unclear. Considering that the increase in pore water pressure can cause rock mass expansion, this paper presents the concept of hydraulic expansion coefficient. First, a cubic model containing spherical pores is established for studying hydraulic expansion, and the ANSYS numerical simulation, a finite element numerical method, was used for calculating the volume change of the model under the pore water pressure. By means of the multivariate nonlinear regression method, the regression equation of the hydraulic expansion coefficient is obtained. Second, based on the hydraulic expansion effect on the rock mass, an interaction model of pore water pressure–porous rock–shaft lining is established and further solved. Consequently, the mechanism of fracturing in shaft lining caused by high-pressure pore water is revealed. The results show that the hydraulic expansion effect on the surrounding rock increases with its porosity and decreases with its elastic modulus and Poisson’s ratio; the surrounding rock expansion caused by the change in pore water pressure can result in the outer edge of the lining peeling off from the surrounding rock and tensile fracturing at the inner edge. Therefore, the results have a considerable guiding significance for designing shaft lining through porous water-rich rock strata.

Research on the Application of Compound Admixture in the Freezing Mine Shaft Lining Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 1252-1255
Author(s):  
Xiang Zong
Keyword(s):  
Experimental Design ◽  
Orthogonal Experimental Design ◽  
Mine Shaft ◽  
Mix Proportion ◽  
Shaft Lining ◽  
Early Strength

In order to achieve the setting and hardening of mine shaft lining concrete under the minus temperature in freezing construction and to meet the demands of every performance of concrete, the technique of compounding air entraining admixture and antifreezing admixture and early strength water reducing admixture was applied in this research. Based on the orthogonal experimental design, several mix proportions of compound admixture for early strength liquid mine shaft lining concrete were developed in the laboratory. The data collected in this research provide reference for the optimum mix proportion of the adulteration quantity of the concrete admixture. The results show that the 2.1％ amount of compound antifreezing admixture achieves favorable effects of liquid, early strength, freezing prevention and antifreezing.

Boulby mine shaft lining design—second restoration

2002 ◽  
Vol 111 (1) ◽  
pp. 13-27
Author(s):  
A. Williams ◽  
F. A. Auld
Keyword(s):  
Mine Shaft ◽  
Shaft Lining
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