نتایج جستجو برای: rock mass explosion

تعداد نتایج: 527134  

2012
Weixing Wang

Since rock fracture is a key property for different rock engineering applications, rock fracture measurement is often carried out in classifying the rock mass. Most geo-mechanics models (e.g. finite element) are of the equivalent continuum type in which fractures are represented not individually, but by their influence on a large element of the rock mass. Elastic modulus, for example, is obtain...

2005

Underground longwall mining of coal causes large scale disturbance of the surrounding rock mass. The disturbance can increase the rock mass permeability through a reduction on the stress as well as formation of new fractures in the rock. Methane gas contained in the disturbed rock mass can migrate towards the low pressure mine workings and present an explosion hazard. This paper describes the a...

Journal: :Journal of Rock Mechanics and Geotechnical Engineering 2018

2018
Marisa Pinheiro Xavier Emery Tiago Miranda Luís Lamas Margarida Espada

Modelling a rock mass in an accurate and realistic way allows researchers to reduce the uncertainty associated with its characterisation and reproduce the intrinsic spatial variability and heterogeneities present in the rock mass. However, there is often a lack of a structured methodology to characterise heterogeneous rock masses using geotechnical information available from the prospection pha...

بخشنده امینه, حسن , مالکی نژاد, حمیدرضا,

The main aim of blasting operations in mining and civil engineering projects is size reduction of the rock-mass. Particle size reduction (P.S.R) affects the efficiency of the loading, haulage and milling equipments. Therefore, prediction of mean fragment size in designing optimum blasting patterns is crucial. In this research, a model is presented for predicting mean fragment size caused by bla...

2005
Justyn R. Maund Stephen J. Smartt

We report our attempts to locate the progenitor of the type Ic SN 2004gt in NGC 4038. We use high resolution HST ACS images of SN 2004gt and have compared them with deep pre-explosion HST WFPC2 F336W, F439W, F555W and F814W images. We identify the SN location on the pre-explosion frames with an accuracy of 5mas. We show that the progenitor is below the detection thresholds of all the pre-explos...

M. G. Mahjani M. Jafarian, Y. Zeraatkish

Electrochemical properties of various rock-shaped-CuO/graphite (G) composites and monoclinic structure CuO nanoparticles as the cathode versus a zinc plate as the anode in a 4M NaOH electrolyte were elucidated by electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP) in a two electrode configuration cell. Various values of G 9, 16 and 28 wt% were prepared and studied as catho...

2013
Qian Zhang Shu-Guang Song

Analysis of advanced displacement in construction progress of tunnel excavation with weak surrounding rock is carried out by numerical method and comparison of model test result. In allusion to the problems of regional landslides and extruded large-deformation seriously impacting the stability of rock mass in construction process of large-section tunnel with weak surrounding rock, the elastic-p...

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