Plastic zones within the rock mass as a function of the shaft lining resistance

2018 ◽  
pp. 325-326
Author(s):  
S. Krstovic
Keyword(s):  
Rock Mass ◽  
Shaft Lining ◽  
Plastic Zones ◽  
Lining Resistance

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.

scholarly journals Three-Dimensional Numerical Analysis of Compound Lining in Complex Underground Surge-Shaft Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Juntao Chen ◽  
Yang Yang ◽  
Chao Ye ◽  
Ying Yang ◽  
Ming Xiao
Keyword(s):  
Rock Mass ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Concrete Lining ◽  
Interface Element ◽  
Nonlinear Fem ◽  
Lining Structure ◽  
Shaft Lining ◽  
Nonlinear Interface ◽  
Computing Method

The mechanical behavior of lining structure of deep-embedded cylinder surge shaft with multifork tunnel is analyzed using three-dimensional nonlinear FEM. With the elastic-plastic constitutive relations of rock mass imported and the implicit bolt element and distributed concrete cracking model adopted, a computing method of complex surge shaft is presented for the simulation of underground excavations and concrete lining cracks. In order to reflect the interaction and initial gap between rock mass and concrete lining, a three-dimensional nonlinear interface element is adopted, which can take into account both the normal and tangential characteristics. By an actual engineering computation, the distortion characteristics and stress distribution rules of the dimensional multifork surge-shaft lining structure under different behavior are revealed. The results verify the rationality and feasibility of this computation model and method and provide a new idea and reference for the complex surge-shaft design and construction.

scholarly journals Investigation of stress field parameters at deep horizons of the Gayskoye field**

2020 ◽  
Vol 192 ◽  
pp. 01028
Author(s):  
Sergey Sentyabov ◽  
Albert Zubkov
Keyword(s):  
Rock Mass ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Concrete Lining ◽  
Complex Structures ◽  
Mining Operations ◽  
Volumetric Expansion ◽  
Shaft Lining ◽  
The Stability

The extraction of solid minerals is associated with the penetration of man into the subsoil by creating either relatively simple or extremely complex structures. All mining operations can be safely and efficiently carried out only on the basis of calculating the stability of these structures, which is based on knowledge of the physical and mechanical properties, the stress state of the rock mass and the patterns of their redistribution and formation in mountain structures. The presented studies confirmed the regularities of the formation of natural stresses in the rock mass, which is the sum of gravitational, static tectonic and variable components, which are formed as a result of uniform periodic volumetric expansion and contraction of the Earth. The problem of shaft stability is due to the need to solve problems to determine the level of stress-strain state and strength properties in concrete lining. The parameters of stresses in the shaft lining and monitoring of their changes were determined using the method of measuring unloading deformations. When analyzing the stresses obtained experimentally by analytical means in the concrete lining of mine shafts, a connection was established with the results of measurements in the rock mass on the basis of 50 meters. Based on the experiment, it was confirmed that theoretical and experimental studies prove that a hierarchically blocky massif of magmatic and metamorphic rocks behaves as an elastic and isotropic medium and changes in natural stresses in the massif Δ on the basis of 5-7 ranks of geoblocks, on the contour of the trunk based on 2 –3 ranks of geoblocks and in the concrete lining of mine shafts Δσb obey this law.

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.

Variations in Mechanical Parameters of Rock Mass Affecting Shaft Lining / Zmiany Parametrów Mechanicznych Górotworu I Ich Wpływ Na Obudowę Szybową

2013 ◽  
Vol 58 (3) ◽  
pp. 629-642 ◽  
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Daniel Wałach
Keyword(s):  
Rock Mass ◽  
Internal Friction ◽  
Soil Properties ◽  
Water Content ◽  
High Water Content ◽  
Mechanical Parameters ◽  
Mass System ◽  
Geomechanical Properties ◽  
Angle Of Internal Friction ◽  
Shaft Lining

Abstract The paper presents geomechanical properties of rock mass occurring in the initial section of shaft lining during its execution. The shaft being sunk is surrounded with cohesive soils, mainly clays with sand layers and silts. Such lithology causes that in various levels some parts of strata are saturated with water. This results in a considerable changeability of soil properties in time. With high water content, the soil is washed away leading to local loss of contact between shaft lining and surrounding soils. This, in turn, results in lack of proper support for curbs and shaft lining fracture in some sections. Engineering activity in such a case should embrace sealing injections in selected parts of the shaft in order to resume proper reinforcement in the lining-rock mass system. The studies of the soils surrounding shaft lining were supposed to help design curbs with increased bearing capacity. The tests of soils indicated that the angle of internal friction and cohesion do change not only at different depths but also at the same depth in different points of perimeter. It was also observed during the study that the mechanical parameters of the analyzed soils improve as the distance from the shaft lining increases, which clearly indicates change of soil properties in the direct neighborhood of the shaft. Considerable number of tests carried out in the study allowed to determine the relationship between water content and angle of internal friction or soil cohesion. The determined relationships can help to estimate change of soil properties under the influence of water with considerable precision. The reinforcement of curbs executed with the use of ground anchors allowed for further shaft sinking. The tests of concrete used in the shaft carried out in the analyzed section produced results similar to the values assumed in the project.

ON PARTIAL CLOSURE OF VARIABLE WIDTH SLIT WITH END ZONES OF PLASTIC DEFORMATIONS IN A ROCK

2020 ◽  
pp. 152-161
Author(s):  
Вагиф Мирахмедович Мирсалимов
Keyword(s):  
Rock Mass ◽  
Singular Integral ◽  
Singular Integral Equations ◽  
Unknown Parameters ◽  
Plastic Deformations ◽  
Partial Closure ◽  
Contact Areas ◽  
Gravitational Forces ◽  
Isotropic Rock ◽  
Plastic Zones

Рассматривается задача о сжатии изотропной горной среды с щелью переменной ширины с концевыми пластическими зонами. Считается, что взаимодействие поверхностей щели под действием тектонических и гравитационных усилий в массиве горной породы может приводить к возникновению зон контакта. Исследуется случай возникновения нескольких участков контакта берегов щели. При этом считается, что на некоторой части площадки контакта возникает сцепление берегов, на остальной части возможно проскальзывание. Нахождение неизвестных параметров, характеризующих частичное закрытие щели, сводится к решению системы сингулярных интегральных уравнений. Определены контактные напряжения, значения размеров участков контакта и концевых зон пластических деформаций. The problem of compression of an isotropic rock medium with a slit of variable width is considered. The slit has end plastic zones. It is assumed that the interaction of slit surfaces under tectonic and gravitational forces in a rock mass can lead to the formation of contact zones. The case of the occurrence of several contact areas of the slit faces is considered. It is assumed that the cohesion of the faces occurs on some part of the contact area, and slippage is possible on the rest. Finding unknown parameters characterizing the partial closure of the slit is reduced to solving a system of singular integral equations. The contact stresses, sizes of contact areas and end zones of plastic deformations are determined.

Full Waveform Acoustic Logging for Slope Weak Layer Evaluation

2012 ◽  
Vol 170-173 ◽  
pp. 159-163
Author(s):  
Zhong Qiu Xie ◽  
Jin Zhao Fan ◽  
Hong Bin Xiao Xiao ◽  
Yu Chi Zhang
Keyword(s):  
Rock Mass ◽  
Acoustic Wave ◽  
Rock Deformation ◽  
Stoneley Wave ◽  
Propagation Characteristics ◽  
Full Waveform ◽  
Filling Ability ◽  
Unstable Failure ◽  
Shaft Lining ◽  
The Relationship

Rock deformation and unstable failure of slope is controlled by weak structural plane whose identification and evaluation is greatly influenced by deformation failure prediction of slope and design treatment. Based on the propagation characteristics of acoustic wave in shaft lining strata, attenuation of stoneley wave and inherent attenuation of strata are analyzed and permeability relationship among shaft lining strata is researched. The relationship between reflected stoneley-wave intensity and the width and filling ability of strata crack is studied. By application example of landslide investigation, attribute parameters and characteristics of acoustic wave are discussed. Strata division, the practicability and accuracy of recognition for fracture and holes evaluation and mechanic characteristics of rock mass also are studied.

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