节理带纵向贯穿异质地层地铁车站施工响应与控制分析

Analysis of construction response and control of subway station with joints running through heterogeneous strata longitudinally

针对辉绿岩侵入花岗岩形成的节理带纵向贯穿异质地层条件下大断面地铁车站施工难题,考虑因辉绿岩侵入形成的节理带特征,以青岛地铁六号线华山一路站施工工程为背景,通过数值模拟与现场监测相结合的研究方法,深入探讨节理带发育影响下地铁车站施工力学响应,分析不同节理带注浆控制方案的支护效应,进而确定合理的针对性控制措施。研究结果表明:由于节理带宽度较大,在无超前支护措施下,车站开挖后应力释放明显,围岩变形达到21.9 mm,无法满足控制的要求。施加超前小导管支护后,车站围岩应力分布明显改善,围岩变形明显减小,节理带范围注浆和拱顶全断面注浆后的拱顶沉降分别为7.13、4.78 mm;注浆加固后塑性破坏范围减小。综合效率及经济问题,根据现场围岩破碎情况,选用节理带范围注浆和拱顶全断面注浆,并且范围注浆情况下宽度为2 m的局部加固方法最优。

Aiming at the construction problem of large-section subway station under the condition that the joint zone formed by diabase intrusion into granite vertically penetrates through heterogeneous strate,considering the characteristics of the joint zone formed by diabase intrusion,taking the construction project of Huashan 1st Rd Station of Qingdao Metro Line 6 as the background,through the research method of combining numerical simulation with field monitoring,the mechanical response of subway station construction under the influence of joint zone development was deeply discussed,and the supporting effects of different joint zone grouting control schemes were analyzed,so as to determine reasonable targeted control measures.The results show that,due to the wide joint zone,the stress release after excavation of the station is obvious,and the surrounding rock deformation reaches 21.9 mm,which can t meet the control requirements.The stress distribution of the surrounding rock of the station is obviously improved and the deformation of the surrounding rock is obviously reduced after the application of advance small pipe support.The settlement of the vault after grouting in the joint zone and the whole section of the vault is 7.13,4.78 mm,respectively.After grouting,the plastic failure range decreases.Considering the efficiency and economic problems,according to the site surrounding rock fragmentation,the joint zone range grouting and the vault full-face grouting are selected,and the local reinforcement method with a width of 2 m is the best in the case of range grouting.The field application results show that the application effect of the research results is good,effectively controlling the deformation of the surrounding rock of large section subway station under complex geological conditions.