盾构隧道穿越高强度强富水灰岩上浮段工程风险分析及应对措施

针对盾构穿越土岩交界面、高强度富水灰岩段及灰岩岩溶区所存在的风险进行分析,合理做好盾构选型,通过工程类比法并结合工程实际提出相应处理措施。采取全土压掘进模式、合理的掘进参数及渣土改良等手段控制土岩交界面上方管线及地表变形;穿越高强度强富水灰岩段,为防止掘进过程中产生"喷涌"现象,采取盾构半敞开式掘进模式、洞内补偿注浆封堵后方来水、地表注射聚氨酯和渣土改良等措施;针对高强度硬岩,通过合理选用刀具、控制盾构掘进参数减少刀具的磨损和破坏。穿越石灰岩岩溶区,针对溶洞的大小、与隧道相对位置关系和充填类型采取地面袖阀管注浆预处理,并结合管片预留孔进行注浆处理,通过采取上述综合技术措施,保证了盾构机在高强度富水灰岩上浮段的顺利掘进。

Engineering Risk Analysis and Countermeasures of Shield Tunnel Passing through Upper Floating Section of High Strength and Water Rich Limestone

According to the analysis of the shield tunnel crossing through earth rock interface,high strength water rich limestone section and limestone karst area,the selection of shield type is well implemented, and corresponding treatmentmeasures are put forward through engineering analogy and engineering practice. To control the deformation of pipelines and ground surface above the earth rock interface,full earth pressure tunneling mode,reasonable tunneling parameters and soil improvement are adopted. In order to prevent the excavation from "gushing "through high strength and strong water rich limestone section,semi open tunneling mode of shield, compensating grouting in hole, surface injection of polyurethane and improvement of residual soil are employed. In the case of high strength hard rock,tool wear and damage can be reduced by selecting appropriate cutters and controlling tunneling parameters. According to the size of the karst cave,relative position relationship and filling type of the karst cave,ground sleeve valve tube grouting and hole grouting are conducted. The above comprehensive technical measures are adopted to ensure smooth tunneling of the shield machine in the upper floating section of high strength water rich limestone.