硬岩地层暗挖斜井对下部既有运营喷锚隧道结构的影响分析

Analysis of Effect on Bolt and Shotcrete Lining of Existing Tunnel Associated with Excavation of Overcrossing Inclined Shaft in Rock Stratum

关于硬岩地层中既有隧道喷锚支护受邻近隧道施工影响产生的变形控制标准的研究很少,依托青岛地铁4号线人民会堂站斜井上跨3号线人汇区间工程为背景,采用MIDAS/GTS计算分析斜井施工对既有运营隧道的影响,并结合自动化监测实测数据进行研究,得到以下结论:采用超前小导坑非爆破+后续爆破扩挖减振爆破方案,产生的爆破振动速度满足爆破控制标准0.5cm/s;硬岩地层喷锚永久结构变形控制标准建议为:竖向及水平收敛≤3mm,爆破振速≤0.5cm/s;硬岩地层隧道施工的主要影响区≤0.5H,次要影响区为(0.5~0.8)H。

In order to fill in the blank in research on overlapping bolt&shotcrete tunnel in rock strata,we choosing Qingdao metro line 4 Renmin Huitang station's inclined shaft which overcross the existing bolt&shotcrete tunnel of metro line 3 as background,adopting automatic monitoring,using MIDAS/GTS to numerical simulate the effect of existing tunnel's bolt &shotcrete lining caused by inclined shaft excavation. The FEA and monitoring results indicate that:the speed of blast vibration is controlled into 0. 5 cm/s with the advanced non-blasting heading and subsequent blasting excavation;the deformation standard of bolt&shotcrete lining tunnel in rock strata is recommended as follows: the vertical&horizontal displacement ≤3 mm,the speed of blast vibration≤0. 5 cm/s;the primary influence area of tunnel excavation in rock strata may be adjust to0 ~ 0. 5 H,the secondary influence area may be adjust toea to(0. 5 ~ 0. 8) H.