A blasting experiment was conducted on iron ore samples by considering multiple coupling charge coefficients. The resulting internal fracture and damage characteristics were quantitatively analyzed via computerized tomography (CT), scanning, three-dimensional (3D) model reconstruction. results show that the primarily displayed radial circumferential cracks along blast hole under an explosive load. When decoupling coefficient small, crack surface dominated transgranular fractures in form of...

AbstractIn order to study the influence of open joint on blasting damage and crack propagation, plexiglass (PMMA) specimens with joints were designed carry out a using digital laser dynamic caustic experimental system. The results showed that could not pass through opening joint. promote destruction medium between borehole Affected by reflected stress wave at joint, was no longer simply subjected tensile stress. Instead, it influenced combined action shear fracture type changed from Type I...

To investigate the influence of boundary effects on damage and fracture characteristics brittle materials under explosive loads, studies were conducted using model experiments simulation methods. The results indicate that outcomes single double models are significantly affected by variation in distance (Δl) between explosion source boundary. When Δl is same, more fragments generated boundaries. circumferential tensile stress, produced superposition incident reflected stress waves at...

Shaped charges are extensively utilized in various rock engineering fields for directional fracturing. Numerous scholars have conducted extensive research on this topic, yielding significant results and widespread application projects. Efforts focused improving the fracture effects fully utilizing energy generated by explosion to enhance blasting of shaped minimize damage mass areas not targeted energy. This approach aims preserve integrity stability unaffected fracture, thereby reducing...

Since the cutting seam cartridge has sound directional breaking effect, in order to explore its blasting wave mechanism, an experimental study was conducted on blast of a using high‐speed laser schlieren system and air overpressure test system. The research results show that during explosion, pipe can effectively control energy release detonation gas dynamic behaviors. Additionally, remain highly symmetrical expansion form. first propagates along direction, initially expands from direction...

To investigate the characteristics of explosion damage from an eccentric decoupled charge, rock-breaking mechanism charge is revealed perspectives wave field and crack through theoretical experimental analyses. The ratio maximum to minimum pressure on hole wall increases exponentially with increase in decoupling coefficient, but it does not change a explosive density or detonation velocity. energy side has certain accumulation effect, velocity reflected shock at blasthole greater than that...

To control the stability of deep well broken surrounding rock, single-hole sonic method is used to test loose circle of-1180 east-rock main roadway and its damage range. The study indicates about 1.8 ~ 2.2 m, which typical large circle. And button slightly larger than two sides’, right side left. rock has some engineering features soft rock. expand deformation does large, difficult support. Combined support usually in this condition.

In hard rock deep‐hole blasting excavation, blastholes are rarely utilized due to the clamping effect of lower rock, which affects excavation progress and restricts development application technology. Cut is a key improving speed. this paper, new cutting method designating two‐step technology was presented. The blasthole divided into upper sections without changing layout. section detonated first, creating sufficient free surface for section, secondly. This created larger cavity improved...

In order to explore the propagation characteristics of explosion wave and gas in blast-hole, design a model simulate blast-hole charge laboratory, adopted high-speed schlieren experiment system used study evolution field under two kinds structures. The results showed similar velocities for cartridges, was reflected when it reaches hole wall, velocity lower than an incident wave. tends cluster spread cutting direction, resulting intensified destruction that direction. first emerges direction...

Layered joints significantly affect the propagation and attenuation of engineering blasting stress waves have a significant influence on rock breakage. In this study, explosion crack mechanism stratified mass with weak or no cementation is analyzed. Multilayer plexiglass plates are employed to simulate layered mass, establishing an experimental model investigate vertical interaction between explosive charges masses. The extent ruptures damage within charging sealing sections cracks at bottom...

Abstract The aim of this study is to explore the fracture dynamic properties defect bodies under explosion loading by using system digital laser caustics test. propagation directional cracks and process have been observed high-speed camera, as well analyzed for changing rules speed stress intensity factors when crack was close defect. Experimental results found that has an inhibitory effect on spreading detonation extended toward With decrease curvature elliptical defect, energy accumulation...

By making use of the experimental system explosive load digital laser dynamic caustics, it is to carry out crack analysis for tip initiation and propagation process precracks near blast hole study directional controlled blastting mechanism, thus obtaining changes displacement, speed, acceleration, stress intensity factor values proecrack in penetration precrack hole.The results indicate that displacement direction on premise experiment far larger than non-precrack direction, caustics speckle...