Coal mining

Geotechnical engineering

Materials science

Overburden pressure

Mining engineering

Excavation

Geology

Brittleness

Coal

Waste management

Rock mechanics

Engineering

Composite material

Rock burst

Tunnelling and Underground Space Technology

High excavation-induced stress concentration and strong mining/tunneling disturbance are prominent conditions in deep excavations, and often present a coupled process to induce rockbursts. This study aims to reproduce and shed light on the rockburst process triggered by hard rock fragmentation using a conical pick. A true triaxial test apparatus was used to apply confining stress and pick force on cubic rock specimen, where the real-time values of the stresses and pick forces were recorded. A high-speed camera system was equipped to shoot the processes of rock fragmentation and rockbursts. The size of fragments produced in rockburst was analyzed via image processing approach. The results show that the cuttability and the rockburst susceptibility of hard rock under high confining stress are correlated with strength parameter and brittleness index of the rock material. Rockburst process consists of three progressive steps: surface slabbing triggered by pick penetration, rapid ejection and violent burst of chips...

Analysis of rockburst triggered by hard rock fragmentation using a conical pick under high uniaxial stress