露天转地下开采覆岩采动响应的坡角影响效应研究

以某矿山露天转地下开采为背景,研究了不同边坡坡角影响下采场上覆岩体的采动响应特征,以揭示覆岩采动响应的坡角影响效应。结果表明,采场内部应力随着矿体开挖推进不断进行重新分布,并持续沿矿层倾向向前方岩体动态转移,在前方形成应力增压区,最终达到新的平衡; 坡高一定时,坡角过大或过小都不利于覆岩的稳定,而是存在一个较为合适的中间值,45°坡角时,采场覆岩比35°和55°模型应力及位移沉降更小,但塑性区发育不及35°及55°模型充分。建议露天开采完后对边坡进行削坡处理,以控制边坡角度45°,然后再转入地下开采。

Slope Angle Effect on Overburden Strata Response During Transition from Open Pit to Underground Mining

Based on the background of transition from open pit to underground mining in one mine, the overburden strata response characteristics in the mining with different slope angle were investigated for exploring the effect of different slope angles on the overburden strata response. It is found that the stress in the stope is continuously redistributed with the advancement of ore body excavation, and continuously shifts to the front rock mass along the joint dip direction of the strata, forming an increasingly pressurized zone in the front before finally reaching a new balance. With a constant slope height, neither too large nor too small slope angle will be beneficial to the stability of overburden strata. Instead, there should be a medium angle for the slope to keep the stability. Compared to the models with slope angle of 35° and 55°, respectively, the model with the slope angle of 45° can lead to the overburden strata with smaller stress and less displacement settlement, as well as a less developed plastic zone. It is suggested that slope cutting treatment should be taken to control the slope angle to be around 45° before the transition from open pit to underground mining.