scholarly journals Mechanical Characteristics of Rock Mass under Loading for Retrofit of Underground Fallout Shelters for Protection of Civil Population

2020 ◽  
Vol 2020 (1) ◽  
pp. 215-223
Author(s):  
Pavel NEUMANN ◽  
Alexander KRAVCOV ◽  
Pawel MACIEJEWSKI ◽  
Jan PRUŠKA ◽  
Michał TOMASZEWSKI
Keyword(s):  
Rock Mass ◽  
Mechanical Characteristics ◽  
Fallout Shelters

Study of Evaluation Method in Terms of Structural Planes Mechanical Characteristics in Engineering Rock Mass

2013 ◽  
Vol 353-356 ◽  
pp. 384-387 ◽  
Author(s):  
Mu Dan Guo ◽  
Fu Sheng Zhu ◽  
Shu Hong Wang ◽  
Xi Jiang Mu
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Efficient Method ◽  
Weight Distribution ◽  
Evaluation Method ◽  
Mechanical Characteristics ◽  
Significant Issue ◽  
Analytic Hierarchy ◽  
Intensity Parameters ◽  
Hierarchy Process

Study of mechanical characteristics of structural planes has been significant issue in engineering rock mass stability analysis. The factors that affect the mechanical behavior of structural planes are so complicated that it is quite essential to take an efficient method to quantificationally analyze these factors. Based on the basic principals of analytic hierarchy process (AHP), a structural plane classification method-CSPC method is proposed. It can conduct weight distribution in terms of the complicated factors, assess the structural planes comprehensively and also forecast the planes intensity parameters semiquantitatively. The classification and forecast parameters of structural planes appropriately fit the cases in engineering. Furthermore, the method is easy to master for the engineers and the application can be of great prospect.

scholarly journals Research on the Layered Rock Mass Excavation Relaxation Stability of Underground Caverns

2020 ◽  
Vol 165 ◽  
pp. 03024
Author(s):  
Ying Zhang ◽  
Heng Zhou ◽  
Shengjie Di ◽  
Xi Lu
Keyword(s):  
Rock Mass ◽  
Mechanical Characteristics ◽  
Generation System ◽  
Yield Zone ◽  
Layered Rock ◽  
Underground Caverns ◽  
Structure Surface ◽  
Layered Rock Mass ◽  
Power Generation System ◽  
The Stability

In order to compare the influence of rock mass parameters weakening on the deformation and stability of excavation caverns in layered rock mass, based on power generation system caverns of a hydropower station, the stability and deformation of the caverns is analyzed. The results show that the mechanical characteristics of the structure surface play a major role in controlling the stability of caverns. And the displacement and yield zone value of plan 3, which adopt elastic-plastic softening model, are significantly larger than other two. The method which consider the residual strength of structure surface is more suitable for the excavation calculation of layered rock mass cavern.

scholarly journals Mechanical Characteristics and Failure Modes of Low-Strength Rock Samples with Dissimilar Fissure Dip Angles

2021 ◽  
Author(s):  
Y L Wang ◽  
D S Liu ◽  
K Li ◽  
X M Hu ◽  
D Chen
Keyword(s):  
Rock Mass ◽  
Mechanical Characteristics ◽  
Failure Modes ◽  
High Strength ◽  
Rock Masses ◽  
Deformation And Failure ◽  
Deformation Features ◽  
Low Strength ◽  
Dip Angle ◽  
Strength Rock

The mechanical characteristics and failure modes of low-strength rock sample with various fissure dip angles were investigated by conventional uniaxial compression test and three-dimensional (3D) crack reconstruction. The results indicated that compared with high-strength rock masses, cracks had different influences on the low-strength rock mass mechanical deformation features. Thereinto, the dip angle of fissures can cause post-peak failure stage of stress-strain curve change from swift decline to multi-step down, showing obvious ductility deformation and failure characteristics. Peak strength and elastic modulus owned an anti-S-shaped growth tendency with the growth of fissure dip angle, which was positively correlated and greatest subtle to the fissure dip angle α < 21° and α > 66.5°. The axial peak strain reduced first and enlarged rapidly with growing fissure dip angle, suggesting a V-shaped change trend. Increasing the fissure dip angle will change the sample failure mode, experienced complete tensile failure to tensile-shear composite failure, and ultimately to typical shear failure. Also, the crack start angle decreased with enlarging fissure dip angle, larger than that the high-strength rock mass fissure dip angle. The above research findings can complement and improve the study of fissured rock masses.

Non-Linear FEM Analysis for the Layered Rock-Mass Tunnel Based on the Twin Shear Strength Criterion

2010 ◽  
Vol 168-170 ◽  
pp. 152-155
Author(s):  
Xiang Qiu Wang ◽  
Zhi Guo Zhou ◽  
Yu Hong Zhang
Keyword(s):  
Shear Strength ◽  
Rock Mass ◽  
Mechanical Characteristics ◽  
Fem Analysis ◽  
Strength Criterion ◽  
Interface Element ◽  
Layered Rock ◽  
Shear Strength Criterion ◽  
Straight Beam ◽  
Layered Rock Mass

According to the geotechnical conditions, A FEM model has been established to analyse the mechanical characteristics of the highway tunnel in the layered rock mass. In this model the layered rock mass and the soften joint are simulated by the transversal isotropic material, the interfaces between layers are simulated by the element of rotational Goodman interface, but the interface between the lining structure and surrounding mass is proposed to simulate by an interface element with thickness, and the supporting of tunnel is simulated by the straight beam element. In the meantime, based on the twin shear strength criterion, the mechanical characteristics of rock, the stiff matrix of element for the layered rock mass, soften joint and interface have been discussed. The analytical model has been demonstrated by comparing the results of layered surrounding rock-mass FEM with the test data in situ.

scholarly journals 2D and 3D seismic measurements to evaluate the collapse risk of an important prehistoric cave in soft carbonate rock

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Giovanni Leucci ◽  
Lara De Giorgi
Keyword(s):  
Rock Mass ◽  
Empirical Analysis ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Mechanical Characteristics ◽  
3D Seismic ◽  
Apulia Region ◽  
2D And 3D ◽  
Seismic Measurements ◽  
Sinkhole Hazard

AbstractThe southern part of the Apulia region (the Salento peninsula) has been the site of at least fifteen collapse events due to sinkholes in the last twenty years. The majority of these occurred in "soft" carbonate rocks (calcarenites). Man–made and/or natural cavities are sometimes assets of historical and archaeological significance. This paper provides a methodology for the evaluation of sinkhole hazard in "soft" carbonate rocks, combining seismic and mine engineering methods.Acase study of a natural cavity which is called Grotta delle Veneri is illustrated. For this example the approach was: i) 2D and 3D seismic methods to study the physical-mechanical characteristics of the rock mass that constitutes the roof of the cave; and ii) scaled span empirical analysis in order to evaluate the instability of the crown pillar’s caves.

scholarly journals ENGINEERING GEOLOGICAL BEHAVIOUR OF HETEROGENEOUS AND CHAOTIC ROCK MASSES

2017 ◽  
Vol 43 (1) ◽  
pp. 183 ◽  
Author(s):  
G. Tsiambaos
Keyword(s):  
Rock Mass ◽  
Mechanical Behaviour ◽  
Mechanical Characteristics ◽  
Rock Masses ◽  
Rock Mass Strength ◽  
Matrix Strength ◽  
The Matrix ◽  
Scientists And Engineers ◽  
Geological Formations

The engineering characterization of heterogeneous and complex geological formations for estimating their rock mass strength and deformability characteristics constitutes a challenge to geo-scientists and engineers dealing with the design and construction of slopes and tunnels. Mélanges and similar heterogeneous mixtures of hard blocks in weaker matrix, known as “bimrocks”, present an overall strength significantly greater than the matrix strength, because the presence of rock blocks, above a threshold volumetric proportion, influences the mechanical characteristics and the behaviour of these rock masses. Moreover, recent studies have shown that the strength and mechanical behaviour of heterogeneous and composite rock masses such as flysch and molasses consisting of alternating layers of competent and incompetent rocks are governed by the presence and volumetric percentage of the interlayers of the weaker rocks.

scholarly journals Experimental study on crack characteristics and acoustic emission characteristics in rock-like material with pre-existing cracks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-Shun Pan ◽  
Shuang-Xi Yuan ◽  
Tong Jiang ◽  
Cheng-Hao Cui
Keyword(s):  
Grain Size ◽  
Acoustic Emission ◽  
Rock Mass ◽  
Axial Load ◽  
Mechanical Characteristics ◽  
Size Range ◽  
Bottom Surface ◽  
Emission Characteristics ◽  
Rock Masses ◽  
Acoustic Emission Energy

AbstractGrain size composition, crack pattern, and crack length have a significant influence on the crack characteristics, mechanical characteristics, and acoustic emission characteristics of rock masses. In this paper, the crack characteristics, mechanical characteristics, and acoustic emission characteristics of rock masses with different grain size compositions, different crack patterns, and different crack lengths were investigated under uniaxial compression. The rock masses were made of rock-like materials. The crack initiation locations and crack propagation directions were different for a specimen comprised of one grain size range compared with specimens comprised of two or three grain size ranges. The specimens comprised of one and three grain size ranges crack progressively. The specimen comprised of two-grain size ranges brittle fracture. The highest peak axial load was found in the specimens comprised of one grain size range. The results showed that tensile wing crack, anti-tensile wing crack, transverse shear crack, compression induced tensile crack, and surface spalling were produced in specimens with different crack orientations. The rock mass with 2 cm long crack started to produce cracks from the tip of the crack extending to the top and bottom surface, soon forming through cracks. The rock was brittle fracture. The axial load reached the maximum and then fell rapidly. The acoustic emission energy reached a rapid maximum and then decreased rapidly. The rock mass with 3 cm long fissures started to produce cracks that only extended from the tip of the fissures to the top surface but not to the bottom surface. The rock mass was progressively fractured. The axial load was progressively decreasing. The acoustic emission energy also rose and fell rapidly several times as the rock mass was progressively fractured. Different rock crack lengths led to different crack processes and crack patterns, resulting in very different acoustic emission characteristics.

Experimental Study on Mechanical Characteristics of Deformation of Red Sandstone

2011 ◽  
Vol 261-263 ◽  
pp. 1234-1238
Author(s):  
Rui Hong Wang ◽  
Yu Zhou Jiang ◽  
Jing Guo ◽  
Shi Yi Wen
Keyword(s):  
Rock Mass ◽  
Elastic Modulus ◽  
Mechanical Characteristics ◽  
Deformation Modulus ◽  
Strain Curve ◽  
Confining Pressure ◽  
Peak Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Red Sandstone

For geotechnical engineering, it has great significance to research the mechanical characteristics of rock mass under three dimensional stresses. Through triaxial compression failure test, the characteristics of stress-strain curve and deformation of red sandstone from Sichuan under different confining pressures has been analyzed. The results show that: with the increment of confining pressure, the failure mode of rock mass changes from brittle failure to ductile failure gradually, and an obvious yield platform appears near the peak strength of stress-strain curve; the elastic modulus, deformation modulus, peak strain and residual strain of rock sample increase with the increment of confining pressure, the elastic modulus and deformation modulus are not a fixed value, and the relation between deformation parameter and confining pressure can be fit through quadratic curve.

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