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...

Under the condition of constant external stress, displacement and stress joint will be adjusted continuously with time, resulting in creep phenomenon, that is, continuous increase strain which further causes damage jointed rock mass. In order to study size effect shear rheological mechanical properties, this paper conducted numerical simulations on nonpenetrating penetrating models established ...

Evaluation of blasting-induced rock damage and fragmentation is very important for safety control construction in the jointed mass. The discontinuous numerical models are commonly applied due to advantages modeling treating discontinuities. In this paper, fracturing algorithm rate dependent strength law incorporated into deformation analysis (DDA) study wave propagation phenomena dynamic proble...

A comprehensive investigation was carried out to minimize the cost price of the rock fragmentation process including: drilling, blasting, secondary blasting and separating the large boulders (oversize rocks) while loading, until the optimized fragmentation, powder factor and ratio of burden (B) to blasthole diameter (?h) were achieved by doing several stages of drilling and blasting practically...

The unique structural characteristics and special symmetry of columnar jointed rock mass result in its complex mechanical properties strong anisotropy, which seriously affects the safety engineering construction. To better simulate natural mass, a geometric model reconstruction method based on single-random movement Voronoi diagram uniform seed points using feasible geological parameters horizo...