Jia Ce, Fan Chaojun, Li Sheng, Liu Xiaoshuai, Luo Mingkun
College of Mining, Liaoning Technical University, Fuxin, 123000, China.
Liaoning Geology Engineering Vocational College, Dandong, 118000, China.
Sci Rep. 2024 Nov 19;14(1):28687. doi: 10.1038/s41598-024-79311-4.
The collapse column may result in failure of the surrounding rock during roadway excavation. It is of considerable importance to elucidate the failure characteristics and develop the corresponding control technologies for the surrounding rock. A discrete fracture mesh (DFN) and a strain-softening constitutive model are employed to simulate the properties of a collapse column. The stress zoning model was developed to characterize the rock surrounding the collapse column. Additionally, the zoned support technology was proposed to stabilize the roadway surrounding the rock. From the center outward, the results indicate that the collapse column can be individually divided into four zones: an internal impact zone of the collapse column, a stress decreasing zone, a stress increasing zone, and an initial stress zone. Upon the visibility of the collapse column, the tensile failure occurs in the roof, leading to a decrease in stress in front of the roadway and an increase in stress on both sides of the collapse column. The collapse amplifies the range of plastic failure by inducing an overlap between the roof stress and the stress elevation zones. The impact zone of the collapse column was reinforced by means of an integrated support system consisting of "pre-grouting, bolt cable mesh, and steel shed". The "bolt cable mesh" provides integrated support beyond the area affected by the collapse column. Following a 20d excavation period, the roof and the two sides were stabilized, with an effectively controlling for the surrounding rock.
陷落柱可能会导致巷道开挖过程中围岩失稳。阐明围岩的破坏特征并开发相应的控制技术具有重要意义。采用离散裂隙网络（DFN）和应变软化本构模型来模拟陷落柱的特性。建立了应力分区模型来表征陷落柱周围的岩石。此外，还提出了分区支护技术以稳定巷道围岩。结果表明，从中心向外，陷落柱可分为四个区域：陷落柱内部冲击区、应力降低区、应力增加区和初始应力区。在陷落柱出现时，顶板发生拉伸破坏，导致巷道前方应力降低，陷落柱两侧应力增加。陷落通过使顶板应力与应力升高区重叠，扩大了塑性破坏范围。采用“预注浆、锚索网、钢棚”一体化支护系统对陷落柱冲击区进行了加固。“锚索网”在陷落柱影响范围之外提供了一体化支护。经过20天的开挖期后，顶板和两侧均得到稳定，围岩得到有效控制。
