Abstract:

Dynamic progressive process of layer separation, bending, sagging and fracturing of overburden strata induced by mining excavation is investigated based on numerical method and the improved Rock Failure Process Analysis code. The simulation result reproduces the formation of caving zone, fractured zone and bend zone. In addition the evolution of fracturing arch and the periodically common nature of strata movement are numerically obtained. It is shown that the overburden strata movement depends on the effect of broken expansion and the tension, shear failure of rock mass. Because the broken expansion of caving rock strata is employed, the fracturing arches do not expand vertically upward, but expand horizontally forward. The top of the arches keeps at the same level and the strata failure is of periodic law. The boundaries of caving zone, fractured zone and bend zone are obviously clear and the surface subsidence is more reasonable. Consequently the numerical results are more consistent with the measured data obtained in-situ.

Key words:

margin: 0cm 0cm 0pt, layout-grid-mode: both, overburden strata')">text-align: justify">overburden strata, damage, bulk factor, numerical simulation