Tunnel reinforcement in columnar jointed basalts: The role of rock mass anisotropy

2015 ◽  
Vol 46 ◽  
pp. 1-11 ◽  
Author(s):  
Yossef H. Hatzor ◽  
Xia-Ting Feng ◽  
Shaojun Li ◽  
Gony Yagoda-Biran ◽  
Quan Jiang ◽  
...  
Keyword(s):  
Rock Mass

scholarly journals The role of modern geodynamic movements in the formation of geomechanical problems in subsoil use

2018 ◽  
Vol 56 ◽  
pp. 02010
Author(s):  
Anatoly Sashourin ◽  
Andrey Panzhin ◽  
July Konovalova ◽  
Vladimir Ruchkin
Keyword(s):  
Rock Mass ◽  
Secondary Structures ◽  
Mineral Deposits ◽  
Scientific School ◽  
Short Term ◽  
Fundamental Properties ◽  
Deformation Processes ◽  
Hazard Level ◽  
Proactive Measures

The paper describes the role of geomechanical processes and phenomena in the development and manifestation of hazardous situations in the development of mineral deposits, threatening the working personnel and the surrounding population. The studies of the Ural Scientific School of geomechanics functioning in the Institute of Mining of Ural Branch of RAS have established that the basis for the formation of hazardous geomechanical processes and phenomena are the fundamental properties of the rock mass - hierarchical blocking and constant mobility caused by the recent geodynamical movements. The constant mobility of hierarchical block medium of rock mass under the influence of trend and short-term recent geodynamical movements gives rise to the phenomenon of the secondary structuring. The recent geodynamical movements concentrate at the borders of the secondary structures and result in the deformations exceeding by 2 - 5 times the intrablock and integral deformations and representing the main source of the hazardous impact on the mining objects and on the surrounding population. The technology of the geological environment diagnostics for the forecast of hazardous mining situations is aimed at the identification of the boundary zones of secondary structures, the estimation of the hazard level of deformation processes and the adoption of proactive measures.

scholarly journals A Preliminary Investigation on the Role of Brittle Fracture in the Kinematics of the 2014 San Leo Landslide

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 256 ◽  
Author(s):  
Davide Donati ◽  
Doug Stead ◽  
Davide Elmo ◽  
Lisa Borgatti
Keyword(s):  
Rock Mass ◽  
Laser Scanning ◽  
Preliminary Investigation ◽  
Intact Rock ◽  
Slope Instability ◽  
Numerical Analyses ◽  
Rock Fracturing ◽  
Bedding Planes ◽  
Synthetic Rock

The stability of high rock slopes is largely controlled by the location and orientation of geological features, such as faults, folds, joints, and bedding planes, which can induce structurally controlled slope instability. Under certain conditions, slope kinematics may vary with time, as propagation of existing fractures due to brittle failure may allow development of fully persistent release surfaces. In this paper, the progressive accumulation of brittle damage that occurred prior to and during the 2014 San Leo landslide (northern Italy) is investigated using a synthetic rock mass (SRM) approach. Mapping of brittle fractures, rock bridge failures, and major structures is undertaken using terrestrial laser scanning, photogrammetry, and high-resolution photography. Numerical analyses are conducted to investigate the role of intact rock fracturing on the evolution of kinematic freedom using the two-dimensional Finite-discrete element method (FDEM) code Elfen, and the three-dimensional lattice-spring scheme code Slope Model. Numerical analyses show that the gradual erosion of clay-rich material below the base of the plateau drives the brittle propagation of fractures within the rock mass, until a fully persistent, subvertical rupture surface form, causing toppling of fault-bounded rock columns. This study clearly highlights the potential role of intact rock fracturing on the slope kinematics, and the interaction between intact rock strength, structural geology, and slope morphology.

Role of Rock Mass Fabric and Faulting in the Development of Block Caving Induced Surface Subsidence

2009 ◽  
Vol 43 (5) ◽  
pp. 533-556 ◽  
Author(s):  
Alexander Vyazmensky ◽  
Davide Elmo ◽  
Douglas Stead
Keyword(s):  
Rock Mass ◽  
Surface Subsidence ◽  
Block Caving

The Finite Element Analysis of Crack Propagating in Bolt-Supported Jointed Rock-Mass

2010 ◽  
Vol 163-167 ◽  
pp. 3453-3456
Author(s):  
Zhong Chang Wang ◽  
Qing Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Element Analysis ◽  
Anchor Cable ◽  
The Finite Element Analysis ◽  
Crack Faces

A new method of inflicting equivalent pre stress is suggested to simulate mechanism on reinforcement of pre stress anchor cable on crack prevention of different angle by mini-plastic zone displacement by finite element method. The change rule of displacement of middle points of crack faces, the change of stress strength gene and strain is compared under different pre-stress consolidated condition. When the angle of crack is 450, the consolidated role of rock mass is the best evident. The effect of compression of jointed rock mass is larger than the effect of shear under pre-stress consolidated condition.

scholarly journals Tunneling in Khimti Hydropower Project, central Nepal

1996 ◽  
Vol 14 ◽  
Author(s):  
S. C. Sunuwar ◽  
B. O'Neill
Keyword(s):  
Rock Mass ◽  
Correct Choice ◽  
The Self ◽  
Hydropower Project ◽  
Supporting Capacity ◽  
Rock Support ◽  
Geological Investigation ◽  
Tunnel Support ◽  
Central Nepal

The role of geology is very important in any underground excavation. Proper geological investigation reduces the overall cost of a project and saves time. It is important to understand and be able to predict the behaviour of a rock mass before designing the support system. In good quality rock, the self-supporting capacity of rock mass should be used to its maximum advantage and the amount of rock support kept to a minimum. In the Khimti Hydropower Project the tunnel support will be designed to take optimum advantage of the self-supporting capacity of rock mass and the correct choice of support systems. The rocks encountered in the tunnels at Khimti will be logged in accordance with the Q-classification system. The experience in desigining tunnel support that has been developed in Norway will be used to this project as well.

Upscaling laboratory measurements: Quantifying the role of hydrothermal alteration in creating geothermal and epithermal mineral resources

2020 ◽  
Author(s):  
Michael Heap ◽  
Darren Gravley ◽  
Ben Kennedy ◽  
Albert Gilg ◽  
Elisabeth Bertolett ◽  
...  
Keyword(s):  
Rock Mass ◽  
Hydrothermal Alteration ◽  
Hydrothermal System ◽  
Geothermal Energy ◽  
Laboratory Data ◽  
Mineral Resources ◽  
Low Permeability ◽  
Fluid Circulation ◽  
Porosity And Permeability

<p>Hydrothermal fluids can alter the chemical and physical properties of the materials through which they pass and can therefore modify the efficiency of fluid circulation. The role of hydrothermal alteration in the development of geothermal and epithermal mineral resources, systems that require the efficient hydrothermal circulation provided by fracture networks, is investigated here from a petrophysical standpoint using samples collected from a well exposed and variably altered palaeo-hydrothermal system hosted in the Ohakuri ignimbrite deposit in the Taupō Volcanic Zone (New Zealand). Our new laboratory data show that, although quartz and adularia precipitation reduces matrix porosity and permeability, it increases the uniaxial compressive strength, Young’s modulus, and propensity for brittle behaviour. The fractures formed in highly altered rocks containing quartz and adularia are also more planar than those formed in their less altered counterparts. All of these factors combine to enhance the likelihood that a silicified rock-mass will host permeability-enhancing fractures. Indeed, the highly altered silicified rocks of the Ohakuri ignimbrite deposit are much more fractured than less altered outcrops. By contrast, smectite alteration at the margins of the hydrothermal system does not significantly increase strength or Young’s modulus, or significantly decrease permeability, and creates a relatively unfractured rock-mass. Using our new laboratory data, we provide permeability modelling that shows that the equivalent permeability of a silicified rock-mass will be higher than that of a less altered rock-mass or a rock-mass characterised by smectite alteration, the latter of which provides a low-permeability cap required for an economically viable hydrothermal resource. Our new data show, using a petrophysical approach, how hydrothermal alteration can produce rock-masses that are both suitable for geothermal energy exploitation (high-permeability reservoir and low-permeability cap) and more likely to host high-grade epithermal mineral veins, such as gold and silver (localised fluid flow).</p>

The role of convergence measurements in characterizing a rock mass

1996 ◽  
Vol 33 (2) ◽  
pp. 363-370 ◽  
Author(s):  
C Derek Martin ◽  
Neil A Chandler ◽  
Rodney S Read
Keyword(s):  
Rock Mass ◽  
Measurement Techniques ◽  
Back Analysis ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Stress Orientation ◽  
Convergence Results ◽  
Convergence Method

Convergence measurements were taken during the construction of a circular shaft in massive granite. The convergence results were used to back-calculate the in situ horizontal stress orientation and magnitudes. The results from the convergence method were supported by other measurement techniques and numerical modelling. Key words: convergence, in situ stress, back-analysis.

The role of seismic methods in investigation of rock mass

2008 ◽  
Vol 56 (4) ◽  
pp. 1065-1073 ◽  
Author(s):  
Iwona Stan-Kłeczek
Keyword(s):  
Rock Mass ◽  
Seismic Methods

scholarly journals The role of digital simulation in assessing and reassessing the potential of complex coal deposits

2020 ◽  
Vol 192 ◽  
pp. 03014
Author(s):  
Vladimir Gavrilov ◽  
Evgenii Khoiutanov ◽  
Natal’ya Nemova ◽  
Dmitrij Son
Keyword(s):  
Rock Mass ◽  
Mineral Content ◽  
Digital Simulation ◽  
Raw Material ◽  
Material Base ◽  
Coal Deposits ◽  
Selective Mining ◽  
External Conditions

The article addresses the increasing complexity of mined or prospective coal deposits. The paper analyses the role of digital simulation in operation assessment and reassessment of the potential of complex in structure coal deposits for more accurate understanding their investment attractiveness, reliability of knowledge on quantity and quality of the reserves. The article stresses the objective need to take into account the realities of the VUKA-world, when companies have to react rapidly to changing of external conditions by adapting organizational and technological measures as much as possible to the constantly overestimated potential of the raw material base. It is of note that reserves should be assessed in accordance with international requirements in the light of the increasing number of parameters for management. The complexity of the structure, the geomechanical heterogeneity of the rock mass, the mineral content of the impurities in the coal, its caking capacity, oxidation and enrichment are taken into account in the estimation. The paper presents the measures to increase the level of utilization of geological potential through the application of selective mining and the control of different quality coal streams in preparation for enrichment and during primary processing.

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