基于压力拱理论的矿块间回采顺序数值模拟

合理的回采顺序能够有效地改善岩体的应力分布状态,有助于保证采场的稳定性。为确定新桥矿-300m中段合理的矿块间回采顺序,根据矿山现有条件,提出3种矿块间回采顺序方案,即平行推进、"品"字形推进、倒"品"字形推进;通过Midas有限元软件对各方案进行数值模拟,综合考虑拉应力、压应力和位移3个因素,运用压力拱理论对模拟结果进行对比分析。结果表明:矿体开挖之后,会在采空区周围形成压力拱,且随着采空区的增加,压力拱的外边界向岩体深部移动;"品"字形回采过程中,中部采空区与两侧采空区在上部可以形成一个更大压力拱,承担其自身和上覆的岩土载荷,其最大拉应力为2.288MPa,最大压应力为23.24MPa,最大位移为55.71mm,均远小于其他2种方案,相比之下,该方案更加合理。经该矿山生产实践表明,"品"字形回采顺序已在矿山推广应用,取得良好的经济、社会效益。

Numerical simulation of stoping sequence among ore block based on pressure arch theory

Rational stoping sequence can effectively improve the stress distribution state of rock mass and ensure the stability of the stope. To determine a reasonable stoping sequence among ore block of Xingqiao Mine -300 m middle section, three schemes of stoping sequence among ore block were put forward according to mine existing conditions, including parallel stoping, Pin-pillar stoping and inverted Pin-pillar stoping, and by Midas finite element software, the numerical simulation models of the shemes were established. Considering the tensile stress, compressive stress and displacement, pressure arch theory was applied to analyze the simulation results. The results show that after the excavation of the ore body, the pressure arch will be formed around the goaf, and with the increase of the goaf, the outer boundary of the pressure arch moves to the deep part of the rock mass; during Pin-pillar stoping process, central part and both sides of goaf form a larger arch to bear its own and overlying rock load. The maximum tensile stress and compressive stress are respectively 2.288 MPa and 23.24 MPa with a maximum displacement of 55.71 mm, which are smaller than those of the other two options. In contrast, the program is more reasonable. The mining practice shows that the production process of Pin-pillar stoping sequence applied in the mine has achieved good economic and social benefits.