Numerical Study of Damage to Rock Surrounding an Underground Coal Roadway Excavation

Figure 8

Characteristics of contact forces. (a) The evolution of contact forces. (b) Diamond pattern of contact forces after excavation. (c) X-shaped tensile stress pattern after excavation. The contact forces were greater where the short line of contact force was wider in (a) and (b) and vice versa. (c) The tensile stress and compressive stress are shown as short lines of the same width to show the X-shaped tensile stress zone (blue represents compressive stress and green represents tensile stress).