نتایج جستجو برای: rock strength

تعداد نتایج: 243114  

2015
Panos Papanastasiou Colin Atkinson

We present a contribution on the risk of hydraulic fracturing in CO2 geological storage using an analytical model of hydraulic fracturing in weak formations. The work is based on a MohrCoulomb dislocation model that is extended to account for material with fracture toughness. The complete slip process that is distributed around the crack tip is replaced by superdislocations that are placed in t...

2017
Rihong Cao Ping Cao Hang Lin Xiang Fan

Joints and fissures in natural rocks have a significant influence on the stability of the rock mass, and it is often necessary to evaluate strength failure and crack evolution behavior. In this paper, based on experimental tests and numerical simulation (PFC2D), the macro-mechanical behavior and energy mechanism of jointed rock-like specimens with cross non-persistent joints under uniaxial load...

2005
R. M. Goktan N. Gunes

In the mining and civil engineering industries point-attack picks (conical picks) are extensively employed on mechanical excavators such as roadheaders, continuous miners and longwall shearers to cut relatively harder rocks/coals compared with radial picks. They are more durable than radial picks, and can economically cut intact rocks having up to around 120 MPa uniaxial compressive strength at...

Slope stability is one of the most important issues in open pit mining design. The main purpose of any open pit mine design is to propose an optimal excavation configuration, considering safety, ore recovery and financial return. An accurate pit slope design which accounts for the mine geology, structural geology, rock mass properties, and hydrogeology models of the mine area, drastically enhan...

2016
Wei Sun Aixiang Wu Kepeng Hou Yi Yang Lei Liu Yiming Wen

The integrated disposal of surface subsidence pits and surface solid waste can be realized by backfilling a surface subsidence area with a paste made from the solid wastes of mines, such as tailings and waste rock. The microstructures of these wastes determine the macroscopic properties of a paste backfill. This paper presents an experimental study on the internal structure evolution of pasty f...

Journal: :international journal of civil engineering 0
m. hassanlourad iran-zanjan-etemadieh h. salehzadeh iran-tehran-narmak h. shahnazari iran-tehran-narmak

the effects of cementation and the physical properties of grains on the shear behavior of grouted sands are investigated in this paper. the consolidated-undrained triaxial shear behavior of three grouted carbonate sands with different physical properties, including particle size distribution, particle shape and void ratio, was studied. two sands were obtained from the north shores of the persia...

2011
G. S. Esterhuizen

Pillars with width-to-height ratios of less than 1.0 are frequently created in underground hard rock mines. The strength of slender pillars can be estimated using empirically developed equations. However, the equations can provide variable results when the width-to-height ratios approach 0.5. This paper investigates some of the issues affecting pillar strength at low width-to-height ratios in h...

2015
Lauren N. Schaefer Jackie E. Kendrick Thomas Oommen Yan Lavallée Gustavo Chigna

In volcanic regions, reliable estimates of mechanical properties for specific volcanic events such as cyclic inflation-deflation cycles by magmatic intrusions, thermal stressing, and high temperatures are crucial for building accurate models of volcanic phenomena. This study focuses on the challenge of characterizing volcanic materials for the numerical analyses of such events. To do this, we e...

Journal: :Journal of anatomy 2006
Adam D Sylvester Angi M Christensen Patricia A Kramer

This study examines the osteological changes in the hands and fingers of rock climbers that result from intense, long-term mechanical stress placed on these bones. Specifically, it examines whether rock climbing leads to metacarpal and phalange modelling in the form of increased cortical thickness as well as joint changes associated with osteoarthritis. This study also attempts to identify spec...

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