富水圆砾与泥岩复合地层泥水盾构超近接下穿既有地铁隧道掘进参数优化研究

On Parameter Optimization for a Slurry Shield Approaching Construction under Existing Subway Tunnels in Water-Rich Pebble and Mudstone Composite Stratum

城市轨道交通的快速发展不可避免地会出现近距离下穿既有隧道的情况,其风险控制主要通过控制掘进参数来实现。基于此,文章依托南宁市轨道交通5号线秀灵路站—明秀路站区间,通过室内相似试验对现场参数进行优化分析,并建立适用于上软下硬复合地层的折线楔形体模型,最后对比研究泥水平衡盾构在全断面泥岩地层段和圆砾泥岩复合地层段中的掘进参数。研究结果表明:通过室内相似试验采用控制变量法对掘进参数进行优化在技术上是可行的;与传统模型相比,假设破坏面近似为折线,更贴合上软下硬复合地层的变形破坏模式;掘进参数在全断面泥岩地层中波动范围较大,其中刀盘扭矩和总推力尤为明显。

Due to the rapid development of urban rail transit,the situation where new tunnels passing under existing tunnels at a close distance is inevitable,and the risk control is mainly achieved by controlling the driving parameters.Based on the running tunnel section between Xiuling Road Station and Mingxiu Road Station of Nanning Metro Line 5,this paper analyzes and optimizes the driving parameters through laboratory similarity tests,and establishes a folded wedge model being applicable to the upper-soft and lower-hard composite stratum,finally it conducts a comparative study regarding the driving parameters of the slurry balance shield in the full-face mudstone strata as well as in the pebble and mudstone composite strata.The study results show that it is technically feasible to optimize the driving parameters by using the control variable method through laboratory similarity tests;compared with conventional models,the hypothesis that the failure surface is approximately assumed as a folded line,is more suitable for the deformation and failure modes of the upper-soft and lower-hard composite stratum;the driving parameters fluctuate in a wide range when the slurry shield in full-face mudstone strata,with the cutterhead torque and total thrust being particularly pronounced.