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本文归纳了用线弹性和非线性的弹-塑性有限元法对于在不同应力场条件下的分段回采巷道的应力分析的结果。从分析中发现,在废石已崩落的分段水平或崩矿的分段水平下面的分段回采巷道将出现临界应力集中。在爆破和放矿的循环中,如果中央回采巷道开采滞后时,将在该进路巷道出现拉伸和剪切破坏。在水平应力场条件下,回采巷道顶板的所有拉伸破坏都不再出现,只有在回采巷道底板上将出现轻微的屈服。与在重力应力场下的分析结果互相比较,当水平应力随着深度增加以后,在分段回采巷道附近的屈服破坏带将会大大变小。然而,预料将有另一种破坏出现,这就是在矿石柱体的测面的中部可能出现过分大的剪应力而导致的剪切破坏。从分段崩落法稳定性的研究中,可以得出两个主要结论:(1)回采巷道的宽度必须仔细地控制在一定的范围内,并且要选择好恰当地回采顺序;(2)分段崩落法可以用于开采深部矿体,如果将矿柱宽度随开采深度而作相应的增加的话。
This paper summarizes the results of the stress analysis of the sectionally extracted roadway under different stress fields by using the linear elastic and nonlinear elastic-plastic finite element method. From the analysis, it is found that the critical stress concentration will occur in the sub-mining roadway below the segmented level where the waste rock has broken down or the subsidence level of the collapsed ore. In the cycle of blasting and ore drawing, tensile and shear failure will occur in the entryway if the recovery of the central mining lane lags behind. Under the condition of horizontal stress field, all tensile failure of mining roof no longer occurs, and only slight yielding will occur on the bottom of mining gateway. Compared with the analysis results in the gravitational stress field, when the horizontal stress increases with depth, the yield failure zone near the sub-mining roadway will be greatly reduced. However, another type of damage is expected to occur, which is shear failure due to the excessive shearing forces that may occur in the middle of the face of the ore column. From the study of the stability of the section caving method, we can draw two main conclusions: (1) The width of the mining roadway must be carefully controlled within a certain range, and the proper sequence of production recovery should be selected; (2) Caving method can be used for deep orebody mining if the pillar width is increased correspondingly with the mining depth.