深埋TBM隧洞岩性界面区围岩破坏特征与支护技术研究

为保证深埋TBM隧洞岩性界面区域的安全、高效施工,综合应用现场调查、微震监测等手段开展顺隧洞轴向岩性界面区域的围岩破坏特征、微震活动特征研究,并在此基础上开展岩性界面区域破坏围岩支护技术研究。研究结果表明： 1）由于岩性界面区域应力集中,开挖卸荷后围岩更容易破坏,且隧洞围岩南硬北软的特征导致不同类型的破坏以蚀变带为界分布在隧洞两侧,破坏分布具有明显的区域性; 2）岩爆、结构型塌方破坏与微震活动具有良好的空间相关性; 3）当岩爆等级较低时,以结构型塌方为主体进行支护,随着岩爆等级升高,支护及防控的主体逐渐过渡为岩爆。

Failure Mechanism and Support Technology ofSurrounding Rocks in LithologicInterfaceArea of Deep Buried Tunnel Bored by Tunnel Boring Machine

To ensure safe and efficient construction in thelithologic interface area of deep buried tunnels bored by tunnelboring machines, field investigationsand microseismic surveys are comprehensively employed to study thecharacteristics of surrounding rock damage and microseismicity in the axiallithologic interface area. On this basis, the support technologies for thesurrounding rock damage in the lithologic interface area are examined. Theresults are as follows: (1) Owing to the stress concentration in the lithologicinterface area, the surrounding rocks are prone to damage after excavation andunloading. The characteristics of hard on the south andsoft on the north of the surrounding rocks cause different types ofdamage, distributed on both sides of the tunnel with the alteration zone as theboundary, and the damage distribution has obvious regionality. (2) There aregood spatial correlations among rockburst, collapse, and microseismicity. (3)When the rockburst grade is low, the structural collapse should bepreliminarily considered when employing a support method. As the rockburstgrade rises, the rockburst should be gradually considered in the supportmethod.