深埋超大断面局部近水平岩层结构垮塌失稳机理

针对深埋超大断面隧道穿越近水平岩层的围岩稳定性问题,建立了局部近水平岩层结构力学模型。认为局部岩层的垮塌失稳为掌子面后方应力重分布形成的均布竖向荷载,及水平荷载作用下结构力学模型的弯拉脆性破坏和剪切塑性屈服过程。通过针对依托工程验证了深埋超大断面隧道,建立局部近水平岩层结构力学模型,分析围岩垮塌失稳的合理性和可靠性;并提出了超大断面深埋隧道近水平围岩失稳后的合理处理措施。研究成果可为深埋超大断面隧道局部近水平岩层结构垮塌失稳及其治理提供理论支持。

Study on mechanism of structural collapse instability in super-large section and deep buried tunnel on local nearly horizontal stratum

For the surrounding rock stability in the super-large section and deep buried tunnel crossing nearly horizontal stratum, structural mechanics model about local horizontal stratum is established, the instability of surrounding rock subjected to vertical uniform load and lateral uniform load due to the stress redistribution in the tunnel face rear is assumed to be a process of the brittle fracture and plastic yield. The reliability and rationality of theoretical analysis of the structural mechanics model of local nearly horizontal stratum in the super-large section and deep buried tunnel is verified through a field case, and reasonable treatment measures are proposed to deal with the instability of super-large section and deep tunnel rock. The present results can be used to analyze the instability of structural collapse model of local nearly horizontal stratum of super-large section deep buried tunnel.