TBM在软弱围岩施工的针对性改造技术

Targeted Retrofitting Technology for TBM Construction in Weak Surrounding Rocks

针对TBM在软弱围岩中掘进易发生卡机、开挖面坍塌等问题,以某工程TBM在稳定性较差的炭质粉砂岩中掘进为例,根据施工现场实际情况,提出了钢管片支护围岩提高撑靴撑紧力;现场更换滚刀刀箱以扩大刀盘开挖直径,提供钢管片安装空间;更换大速比主驱动减速机以提高刀盘脱困扭矩以利于TBM脱困,优化护盾结构以满足护盾内超前钻孔支护围岩,在护盾内增加辅助推进系统以提高TBM推力,主梁二处增加辅助调向模块,用于钢管片拼装模式推进及调向;增加管片拼装系统进行钢管片拼装。TBM改造后顺利、快速地穿过围岩破碎带,有效解决了软弱围岩(破碎带)卡机的问题,实际工程验证了TBM现场改造方案的可行性。

For TBM boring in weak surrounding rocks is prone to jamming and excavation surface collapse,this paper takes the example of a project TBM tunneling in poorly stabilized carbonaceous siltstone,based on the actual situation at the construction site,we propose to improve the bracing force of the steel pipe sheet to support the surrounding rock;replace the hob cutter box on site to expand the excavation diameter of the cutter and provide space for steel pipe sheet installation;replace the main drive reducer with a large speed ratio to increase the torque of the cutter to facilitate the extrication of the TBM;optimize the shield structure to meet the over-drilling in the shield to support the surrounding rock;add an auxiliary propulsion system in the shield to improve the thrust of the TBM;add an auxiliary adjustment module at the second main beam for the propulsion and adjustment of the steel pipe sheet assembly mode;and add a pipe sheet assembly system for steel pipe sheet assembly.The reconstructed TBM passes through the surrounding rock fracture zone smoothly and quickly,which effectively solves the problem of machine-blocking in weak surrounding rock(fracture zone).The feasibility of site transformation program of TBM has been verified in practical engineering.