基于FDM−DEM耦合数值计算的层理性质对顶板稳定性的影响研究

    Study on the influence of bedding properties on roof stability based on FDM-DEM coupled numerical simulation

    • 摘要: 为探明层理性质对巷道顶板稳定性的影响,创建了一个耦合了有限差分法(FDM)和离散元法(DEM)的3D数值模型。模型中,巷道两帮、底板和远场围岩由FLAC3D创建的连续介质区域进行模拟,巷道层状顶板岩层基质则由PFC3D中的黏结颗粒流(BPM)创建,层理则通过添加具有特定刚度和强度的平行弱面实现。研究中通过改变弱面的强度模拟层理性质不同时层状顶板在掘进卸荷作用下的破裂特征。研究结果表明:完整顶板中的裂隙分布呈穹顶状,而层状顶板的裂隙则沿弱面分布,层状顶板的破坏从临空层开始并往内部扩展;层理强度的增加会改变顶板中的应力场分布,进而影响顶板中的裂隙发育进程。PFC3D/FLAC3D的耦合策略能有效再现煤矿中的层状顶板在巷道开挖卸荷作用下的裂隙发育过程。

       

      Abstract: In order to reveal the influence of bedding properties on the stability of coal mine roadway, the study established a 3D numerical model combined finite differential method (FDM) coupling discrete element method (DEM). In the model, the two sides of the roadway, the floor and the far-field surrounding rock are simulated by the continuous medium domain created by FLAC3D, while the layered roof rock mass of the roadway is created by the bonded particle model (BPM) in PFC3D, and the bedding planes are realized by adding parallel weak planes with specific stiffness and strength. In the study, the properties of the bedding were simulated by varying the strength of the weak plane to investigate the fracture characteristics of the layered roof under the action of excavation and unloading. The results showed that the fracture distribution in the intact roof was dome-shaped, while the fractures in the layered roof were distributed along the weak plane. The failure of the layered roof started from the layer adjacent to the goaf and expanded inward. The increase in bedding strength will change the stress field distribution within the roof, and to alter the development process of fractures in the roof. The coupling strategy of PFC3D/FLAC3D can effectively reproduce the fracture development process of the layered roof in coal mines under the action of roadway excavation and unloading.

       

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