Peng Rui, Meng Xiangrui, Zhao Guangming, Li Yingming, Zhu Jianming
School of Safety Engineering, North China Institute of Science & Technology, Beijing, China.
Department of Energy and Security, Anhui University of Science and Technology, Huainan, Anhui Province, China.
PLoS One. 2018 Feb 15;13(2):e0192470. doi: 10.1371/journal.pone.0192470. eCollection 2018.
We study the structural instability mechanism and effect of a multi-echelon support in very-deep roadways. We conduct a scale model test for analysing the structural failure mechanism and the effect of multi-echelon support of roadways under high horizontal stress. Mechanical bearing structures are classified according to their secondary stress distribution and the strength degradation of the surrounding rock after roadway excavation. A new method is proposed by partitioning the mechanical bearing structure of the surrounding rock into weak, key and main coupling bearing stratums. In the surrounding rock, the main bearing stratum is the plastic reshaping and flowing area. The weak bearing stratum is the peeling layer or the caving part. And the key bearing stratum is the shearing and yielding area. The structural fracture mechanism of roadways is considered in analysing the bearing structure instability of the surrounding rock, and multi-echelon support that considers the structural characteristics of roadway bearings is proposed. Results of the experimental study indicate that horizontal pressure seriously influences the stability of the surrounding rock, as indicated by extension of the weak bearing area and the transfer of the main and key bearing zones. The falling roof, rib spalling, and floor heave indicate the decline of the bearing capacity of surrounding rock, thereby causing roadway structural instability. Multi-echelon support is proposed according to the mechanical bearing structure of the surrounding rock without support. The redesigned support can reduce the scope of the weak bearing area and limit the transfer of the main and key bearing areas. Consequently, kilometre-deep roadway disasters, such as wedge roof caving, floor heave, and rib spalling, can be avoided to a certain degree, and plastic flow in the surrounding rock is relieved. The adverse effect of horizontal stress on the vault, spandrel and arch foot decreases. The stability of the soft rock surrounding the roadways is maintained.
我们研究了极深巷道中多级支护的结构失稳机制及效果。进行了相似材料模型试验，以分析高水平应力作用下巷道的结构破坏机制及多级支护效果。根据巷道开挖后围岩的二次应力分布及强度劣化情况，对力学承载结构进行分类。提出了一种新方法，将围岩的力学承载结构划分为软弱、关键和主耦合承载层。在围岩中，主承载层是塑性重塑流动区，软弱承载层是剥落层或冒落部分，关键承载层是剪切屈服区。在分析围岩承载结构失稳时考虑了巷道的结构破坏机制，并提出了考虑巷道承载结构特征的多级支护。试验研究结果表明，水平压力严重影响围岩稳定性，表现为软弱承载区扩展以及主、关键承载区转移。顶板冒落、两帮片帮和底鼓表明围岩承载能力下降，从而导致巷道结构失稳。根据无支护时围岩的力学承载结构提出了多级支护方案。重新设计的支护可减小软弱承载区范围，限制主、关键承载区转移。因此，可在一定程度上避免千米深巷道的灾害，如楔形顶板冒落、底鼓和两帮片帮，减轻围岩塑性流动。水平应力对拱顶、拱肩和拱脚的不利影响减小，维持了巷道围岩的稳定性。
