Assessment of influence of short-period geodynamic movements on stress-strain behavior of rock mass

2020 ◽  
pp. 90-104
Author(s):  
Yu. P. Konovalova ◽  
V. I. Ruchkin
Keyword(s):  
Rock Mass ◽  
Strain Tensor ◽  
Space Distribution ◽  
Cycle Duration ◽  
Stress Strain ◽  
Strain Behavior ◽  
Principal Axes ◽  
Short Period ◽  
Check Points ◽  
Cyclic Movement

Geodynamic diagnostics of rock mass is critical in terms of safe arrangement and operation of subsoil use objects. The modern geodynamic movements are one of the factors that govern the stress-strain behavior of rocks. The experimental research accomplished in the recent decades show that geodynamic movements are the wide-spread phenomena of complex time-and-space distribution. It is conditionally assumed to distinguish between the trend movements of the same direction and velocity over the period of observations and the cyclic short-period movements with cycle duration from a few minutes to a few hours. The cyclic short-period geodynamic movements can exert direct or indirect impact on subsoil use objects. The cyclic nature is governed by many natural factors. The influence of one or another factor on the stress-strain behavior of rock mass is yet unstudied unambiguously to date. However, it is evident that strains governed by the cyclicity of movements should be taken into account in geodynamic diagnostics. The implemented studies of short-period movements on testing grounds by continuous monitoring using GNSS methods for many hours at spacing from two hundred meters to two kilometers revealed that directions of displacement of check points frequently exceeded accuracy of their determination. During the experiments, a procedure was developed to determine parameters of strain tensor in rock mass based on the prevailing direction and amplitude of short-period movements. The amplitude of short-period movement is a difference between the minimal and maximal values of displacements in a set of discrete measurements within continuous observation session. The obtained field of strains was compared with the values calculated by the data on the trend geodynamic movements for 6 years with the same check points in the same pattern. The correlation is found between the orientations of principal axes of strain tensors calculated by the data on the trend and shortperiod movements. The developed procedure makes it possible to take into account the shortperiod cyclicity of the modern geodynamic movements, and the found correlation between the orientation of strain tensor of the trend and cyclic movement enable express estimation of changes in the stress-strain behavior of rocks.

Joint analysis of rock mass stress state and elasticity modulus during shaft sinking

2020 ◽  
pp. 21-36
Author(s):  
A. E. Balek ◽  
I. L. Ozornin ◽  
A. N. Kayumova
Keyword(s):  
Rock Mass ◽  
Elasticity Modulus ◽  
High Strength ◽  
Joint Analysis ◽  
Processing Plant ◽  
Stress Strain ◽  
Strain Behavior ◽  
Geological Conditions ◽  
Check Points ◽  
Strength Rock

The article presents an innovative procedure for the joint stress-strain and elasticity modulus analysis in high-strength rock masses with spacing from a few to tens meters. The procedure includes measurement of elastic convergence of rock walls due to deeper penetration of the foot of a vertical shaft and the analysis of measured displacements of check points along the shaft cross-section perimeter with subsequent two-stage solution of an inverse geomechanical problem. In the first stage, in the lobed diagram of measured displacements of check points, the azimuths of axes of the principal horizontal stresses in surrounding rock mass are determined. In the second stage, the process of deeper penetration of the shaft foot is modeled with different scenarios of the rock mass stress-strain behavior set as varied principal horizontal stresses at the known azimuths of their main axes. Then, the model and in-situ measurement results are compared using the analysis of variance ANOVA. The wanted variant of the stress-strain behavior and the associated modulus of elasticity, such that deviation of the actually measured displacements of check points from the model values is minimal, is identified by the extremum analysis of the experimental diagrams. The procedure was successfully tested in Vspomogatelny and Skipovoi vertical shafts of the Tenth Anniversary of Independence of Kazakhstan mine within Donskoy Mining and Processing Plant, in qualitatively different geological conditions: high-strength rock mass areas categorized as unstable and stable. In unstable rocks, the measured elasticity modulus Е = 3,5 ± 0,7 GPa made 6 %-16 % of the elasticity modulus in samples. In the stable rock mass, the measured modulus Е = 36,6 ± 7,7 GPa almost coincided with the elastic modulus of samples.

Change in stress-strain behavior of coal-rock mass during coal mining

2020 ◽  
pp. 5-24
Author(s):  
V.N. Zakharov ◽  
A.V. Shlyapin ◽  
V.A. Trofimov ◽  
Yu.A. Filippov
Keyword(s):  
Rock Mass ◽  
Coal Mining ◽  
Stress Strain ◽  
Strain Behavior ◽  
Coal Rock

3D finite element-based modeling of discontinuities

2020 ◽  
pp. 35-39
Author(s):  
I. E. Semenova ◽  
◽  
S. V. Dmitriev ◽  
A. A. Shestov ◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Strain Analysis ◽  
Interface Element ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Interface Elements ◽  
Strain Behavior ◽  
Improve Reliability ◽  
Optimal Type

A rock mass is composed of blocks, and the interfaces of various scale blocks represent different kind discontinuities. Such structure is also associated with nonuniformity of stresses. The stress–strain behavior of rock mass in the Khibiny apatite–nepheline massif in the course of mining is governed by natural geological and induced faulting. This study considers modification of the finite element method in the stress–strain analysis of rocks with regard to deformation at interfaces of different-modulus media. After 2D tests of interface elements, an optimal type of the interface element was selected for the 3D modification implementation. The latter can improve reliability of geomechanical forecasts in mineral mining in complicated geological and geodynamic conditions. From the test data on modification of interface elements, the optimal interface element is assumed to be the six-node interface element proposed by V. Kalyakin and Jianchao Li. The six-node interface element is introduced in the model of a tunnel with simulation of an unloading line at the boundary. The adequate results on adjacent rock deformation are obtained. The 3D interface element modification reveals its peculiarities and limitations as regards introduction in finite element models of mineral deposits and enclosing rock mass. The ways of solving these problems are proposed.

scholarly journals STRESS-STRAIN BEHAVIOR OF ROCK MASS AROUND CYLINDRICAL EXCAVATIONS WITH THE PRESET CAUCHY STRESS STRESSES AND DISPLACEMENTS AT THE BOUNDARIES

2021 ◽  
Vol 2 (4) ◽  
pp. 158-163
Author(s):  
Anvar I. Chanyshev ◽  
Igizar M. Abdulin
Keyword(s):  
Rock Mass ◽  
Symmetry Axis ◽  
Strain Analysis ◽  
Polar Angle ◽  
Surrounding Rock ◽  
Rotation Vector ◽  
Cauchy Stress ◽  
Stress Strain ◽  
Strain Behavior

The authors solve the problem on the stresses and strains of rock mass around a cylindrical excavation with the preset vectors of the Cauchy stresses and displacements at the boundary. It is assumed that the surrounding rock mass is elastic. Along the cylindrical excavation (free of stresses), displacements are measured as functions of two surface coordinates (polar angle and length along the symmetry axis of the excavation). These measurements are used to determine all components of tensors of stresses and strains at the boundary, and all coordinates of rotation vector. It is shown how this information can be used in the stress-strain analysis of rock mass farther from the excavation.

Stress-strain behavior control in rock mass using different-strength backfill

2020 ◽  
pp. 42-55
Author(s):  
A.M. Khayrutdinov ◽  
Ch.B. Kongar-Syuryun ◽  
T. Kowalik ◽  
Yu.S. Tyulyaeva
Keyword(s):  
Rock Mass ◽  
Behavior Control ◽  
Stress Strain ◽  
Strain Behavior

Observations of the Constitutive Response and Characterization of Filled Natural Rubber Under Monotonic and Cyclic Multiaxial Stress States

2004 ◽  
Vol 126 (1) ◽  
pp. 19-28 ◽  
Author(s):  
W. V. Mars ◽  
A. Fatemi
Keyword(s):  
Natural Rubber ◽  
Combined Loading ◽  
Stress Strain ◽  
Strain Behavior ◽  
Filled Rubber ◽  
Short Period ◽  
Wide Range ◽  
Recent Developments ◽  
Constitutive Response ◽  
Stress States

This work explores the monotonic and cyclic behaviors of filled, natural rubber. Results of stress-strain experiments conducted under stress states of simple, planar, and equibiaxial tension are presented. The ability of hyperelastic models to capture the observed response, as well as recent developments in constitutive modeling of filled rubber such as the consequences of the Mullins effect, are discussed. Monotonic and cyclic multiaxial experiments were also conducted using a short, thin-walled, cylindrical specimen subjected to a wide range of combined axial and twist displacements. Experiments included pure axial tension, pure torsion, combined loading in which the axial and torsion displacements varied proportionally, and combined loading in which the axial and torsion displacements varied non-proportionally (phase between axial and torsion channels of ϕ=0 deg, 90 deg, 180 deg). Results from these tests are presented and discussed, including evolution of stress-strain behavior with load cycles, and the effects of a short period of initial overloading on the subsequent evolution of the stress-strain response.

Alteration of initial stress state in the north area of the Sokolov deposit in the course of mining

2020 ◽  
pp. 138-148
Author(s):  
D. A. Mengel
Keyword(s):  
Acoustic Emission ◽  
Rock Mass ◽  
Stress Strain ◽  
Influence Zone ◽  
Initial Stress State ◽  
Strain Behavior ◽  
The North ◽  
The Subject ◽  
Major Factors ◽  
Underground Method

The stress-strain behavior of rocks is one of the major factors which govern the value and nature of strata pressure, while the latter in many ways determines the safety and efficiency of underground mineral mining. The subject of the research is the stress-strain behavior of rock mass in the north of the Sokolov deposit developed by the underground method. The aim of the research is to study the change in the stress-strain behavior in the north area of the Sokolov deposit in the course of mining. The methods of the research involve the analysis of the stress-strain behavior measured instrumentally using the borehole slotter technique and the comparison of the data with the instrumental measurements of acoustic emission by GS-01 device. The analysis yields that mined-out space has influence on the stress-strain behavior of rocks, while the effective loads across the orebody strike beyond the influence zone of the mined-out area remain yet high and approach the initial values.

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