青岛地铁穿越富水弱胶结地层支护方案优化研究

为解决青岛地铁穿越富水弱胶结地层隧道安全快速施工难题,针对隧道上部天然隔水层保护前提下的支护方案优化,考虑支护结构对围岩稳定性控制的影响,通过数值模拟分析了不同支护方案下隧道开挖后围岩变形规律与塑性区扩展特征;基于隧道上覆岩层塑性区范围、隧道沉降和收敛值等控制指标优化了支护方案,并结合Peck公式采用非线性拟合方法建立了地表变形预测公式。结果表明:以超前小导管结合超前锚杆的联合支护体系能够有效控制隧道开挖围岩变形,并对上覆隔水层起到一定保护作用,优化后支护方案安全、合理、高效,为类似条件下的地铁隧道变形控制及快速施工提供了理论依据和技术指导。

Optimization of Supporting Scheme for Water-rich and Weakly Consolidated Strata Tunnel of Qingdao Metro

In order to solve the problems of safety and fast construction in water-rich and weakly consolidated strata tunnel of Qingdao metro, a numerical simulation model established by threedimensional fast lagrangian method is used to optimize supporting scheme without destroying the upper natural aquifer. Considering the influence of the supporting structure on the stability of surrounding rock,this paper analyzes the deformation law of surrounding rock and the extension of the plastic zone after tunnel excavation. Supporting scheme is optimized according to the displacement of surrounding rock and the plastic area of overlying strata,and the formula for prediction of surface deformation is set up by using non-linear fitting method based on Peck formula. The results show that the combined supporting with advanced small pipe and advanced anchor can effectively control the deformation of tunnel excavation,protect the overlying water-resisting layer, and provides theoretical references and technical guidance for deformation control of metro tunnels and rapid construction.