The progress of failure of mining developed cavern and its influence on the ground surface

采矿开发洞室破坏进展及其对地表的影响

• 批准号: 10650915
• 负责人: SAITO Toshiaki
• 金额: $ 1.73万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650915/
• 关键词: cavern; failure of rock mass; long-term stability; ground surface; FEM; elasto-plastic aualysis; rock fall

From the standpoint of safety and environment keeping in a mine, it is important to discuss what conditions make the failure of mining developed caverns affect the ground surface, what conditions induce large-scale failure of the caverns and what is the minimum volume of filling to prevent such failure. To do this based on rock mechanics, we proposed an elasto-plastic analysis method using FEM assuming that the caverns have passed very long time and the strength of rock has been lower enough. Then, we applied this method for the large caverns of a mine. As the results, it was cleared that the failure of the caverns will progress about 100m upper to the caverns but will not affect the ground surface. Next, in order to clear the conditions as mentioned above, we applied this method for the many equally separated caverns under a flat surface. In this analysis, eight cases set by changing the depth of the caverns, the width of pillars and the stress ratio of horizontal direction to vertical direction were considered. Consequently, the followings were cleared. The progress of the failure does not affect the surface when the depth of caverns is deeper than the twice of caverns' height and the width of the pillars is larger than the twice of caverns' width. Furthermore, the large-scale failure rarely occurs when the stress ratio is as large as three and the width of the pillars is larger than the twice of caverns' width. These results were derived from the analysis only for eight cases. Therefore, in order to get more general results, we must study for much more cases.

从矿山安全和环境保护的角度出发，探讨在哪些条件下开采发育的洞室破坏会对地表造成影响，在什么条件下会引起大规模的破坏，以及防止这种破坏的最小充填量是什么，这是非常重要的。为此，基于岩石力学原理，提出了一种基于有限元的弹塑性分析方法，假定洞室经过很长时间后，岩石的强度已经足够低。然后，将该方法应用于某矿山大型洞室。结果表明，洞穴的破坏将延伸到洞穴上方约100米处，但不会影响地面。接下来，为了清除上述条件，我们将这种方法应用于平坦表面下许多等间距的洞穴。在该分析中，考虑了洞室深度、柱子宽度和水平方向与垂直方向的应力比变化所设置的八种情况。因此，以下内容被清除。当洞室深度大于洞室高度的两倍，且柱子的宽度大于洞室宽度的两倍时，破坏的进展不影响地表。当应力比大于3，且柱子宽度大于洞室宽度的两倍时，较少发生大范围破坏。这些结果仅从8个案例的分析中得出。因此，为了得到更普遍的结果，我们必须研究更多的案例。