Strainburst is the most common type of rockbursts. The research strainburst damage mechanisms helpful to improve and optimize rock support design in burst-prone ground. In this study, an improved global-local modeling approach was first adopted study mechanisms. extracted stresses induced by multiple excavations from a three-dimensional (3D) global model established fast Lagrangian analysis continua 3 dimensions (FLAC3D) are used as boundary conditions for two-dimensional (2D) local deep...

The article presents a method of selecting an arch yielding support for preparatory workings driven in hard coal seam. Particular attention was paid to discontinuous deformation the form fault, which significantly contributes change excavation protection schemes. On basis geometry machines and devices designed excavation, selected, then checked ventilation criterion. In next stage, analytical calculations were carried out using determined spacing steel fault zone area outside it....

In this paper, a 2D distinct element method (DEM) model of deep tunnel in an underground coal mine is built to thoroughly evaluate the effects yielding (D-bolt and Roofex) traditional rockbolt (fully resin-grouted rebar) on controlling self-initiated strainbursts. The occurrence strainbursts judged based stiffness difference between loading system rock masses for first time. results suggest that total deformations supported with Roofex rebar are 1.53 2.09 times D-bolts (1411 mm). average...

Abstract The assessment of yielding rockbolt performance during rockbursts with actual seismic loading is essential for rockburst supporting designs. In this paper, two types rockbolts (D-bolt and Roofex) the fully resin-grouted rebar bolt are modeled via “rockbolt” element in universal distinct code (UDEC) after an exact calibration procedure. A two-dimensional (2D) model a deep tunnel built to evaluate (e.g., capacity energy-absorption control rock damage) traditional based on simulated...

Drilling and blasting is still the most widely used method for tunnel excavation in hard rocks. However, this causes damage to adjacent buildings structures mainly because of blast-induced vibrations. Currently, no specific guidelines are available optimizing design damping holes during controlled blasting. Therefore, study analyzes vibration reduction mechanism holes. Six key factors, namely, hole radius, spacing, coverage length, arrangement type, number rows, row that can affect were...

Large diameter pipelines with different cross-sectional shapes and numerous aging cracks are prone to cause severe accidents when subjected close-proximity blasting excavation for tunnel construction. The propagation law of seismic wave the characteristics longitudinal transverse vibration response three were obtained using explicit dynamic finite element software LS-Dyna. results revealed that under action load, failure points circular, square horseshoe-shaped located at midpoint side wall,...

In order to study the mechanism of dual side roof cutting technology on composite disaster gas and coal spontaneous combustion in goaf, a model for evolution porosity permeability working face was constructed. The location occurrence compound explosion under double-sided mode studied, sensitivity pattern area amount air supply gush summarized. results indicate that top pressure relief significantly reduces porous media, goaf intake airflow disturbances is reduced. As volume increases,...

Vibration induced by near-field tunnel blasting can easily damage the surrounding rockmass. The vibration response, characteristics and attenuation law in front rear of face were studied under different types holes blasting. A new prediction method for near field PPV was proposed based on far monitoring data. results showed that maximum rockmass generated peripheral blasting, propagation distance key influencing factor. In contrast, away from cutting conditions free charge weight had a...

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operations underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability workings and then ground whole mine site. However, backfilling step scenarios vary from site to paper presents investigation five different their impacts on stopes at four mining levels. A comprehensive comparison displacements, major principal stress, Stress Concentration Factor (SCF) was conducted. The results...

Large diameter pipelines with different cross-sectional shapes and numerous aging cracks are prone to cause severe accidents when subjected close-proximity blasting excavation for tunnel construction. The propagation law of seismic wave the characteristics longitudinal transverse vibration response three were obtained using explicit dynamic finite element software LS-Dyna. results revealed that under action load, failure points circular, square horseshoe-shaped located at midpoint side wall,...

As a typical sedimentary rock, coal seams are usually rich in bedding planes, which significantly affect the propagation process of hydraulic fracture (HF) network and reservoir permeability. In this study, profile characteristics roughness seam at depth 2800 m from Daniudi Gas Field China is investigated. The failure mechanism shear-expansion effect under low pressure dynamic shear high beddings induced by dissolution-corrosion fracturing liquid analyzed. development HF different angles,...

Many mines in Canada have adopted sublevel stoping method or one of its variations, such as blasthole (BHS) and longhole retreat (SLR), for the extraction steeply dipping orebodies. Stope, basic excavated element, plays a significant role whole process mining activity. In BHS, crossing cuts are at tops bottoms each stope drilling blast holes transportation mined out Crossing failure may result prolonged production interruption, fatality, equipment loss. After completion orebodies excavation...

In Canada, many mines have adopted the sublevel stoping method, such a blasthole (BHS), to extract steeply deposited minerals. Sill pillars are usually kept in place this mining method support weight of overburden underground mining. To prolong mine's life, sill will be recovered, and pillar recovery could cause failures, fatality, equipment loss stopes. paper, three schemes-SBS, SS1, SS2-were proposed conducted assess feasibility recovering two hard rock mine by developing full-sized...

To extract steeply dipping orebodies, many mines in Canada have adopted the sublevel stoping method, such as blasthole (BHS) and longhole retreat (SLR).In methods, sill pillars are initially kept place to support weight of overburden underground mining.After stope mining is complete, voids will be backfilled with cemented rockfill (CRF).The strength CRF affects stability adjacent stopes pillar recovery excavation scheme.Sill may cause prolonged failure, fatality, equipment loss.Choosing a...

Keywords: underground engineering; numerical simulation; excavation length effect, major principal stress; displacement; damage initiation; CPU time

Cemented rock fill (CRF) is commonly used in cut-and-fill stoping operation underground mining. This allows for the maximum recovery of ore. Backfilling can improve stope stability workings, and then ground whole mine site. step scenarios vary from site to paper presents investigation five different backfilling their impacts on stopes at four mining levels. A comprehensive comparison displacements, major principal stress concentration factor (SCF) was conducted. The results show that have...