喜马拉雅山区域深埋软硬互层地质条件下敞开式TBM施工方法研究

Research on Construction Technologies for Open TBM in Deep-buried Soft and Hard Alternant Strata in Himalayas

针对敞开式TBM在深埋软硬互层围岩地质条件下遇到的技术难题,以喜马拉雅山区域某深埋水工隧洞为背景,分析了深埋软硬互层围岩地质条件下软岩对TBM掘进的影响及表现特征,提出了针对性的解决措施并成功实践。研究发现:由于岩层软硬相间变化频繁,造成软岩灾害在空间上随机分布;在大埋深高地应力洞段,软岩地层一般具有遇水崩解软化效应显著、变形快、"泥裹刀"现象严重、向外鼓胀崩解、难以出渣及塌方频发的特点,严重制约TBM快速掘进。通过实例分析总结了软硬互层围岩地质条件下顺利通过软岩的施工方法,采取分区段动态调整施工对策以适应深埋软硬互层复杂地质条件,可为国内外类似工程提供借鉴。

The influence of soft layer on TBM boring in deep-buried soft and hard alternant strata and its characteristics are studied by taking a deep-buried tunnel in Himalayas for example. Some effective construction countermeasures are put forward and put into practice successfully. The results show that ： 1 ） The distribution of soft rock disasters is random in space due to that the hard and soft layers alternate frequently. 2） In deep-buried tunnels with high ground stress, the TBM tunneling progress is restricted to the soft layer with the characteristics of water softening significantly, great deformation speed, serious mud muffled of cutters, expansion, hard be mucked and collapses frequently. The construction methods for TBM tunneling through soft and hard alternant strata are summarized; and sectioned dynamic construction countermeasures are adopted. The results can provide guidance for similar projects in China and abroad in the future.