北宜高速公路雪山隧道竖井止水灌浆成果对开挖进度之影响

The Different Grouting and Excavation Methods of Ventilation Shafts in Hsueshan Tunnel

地下水影响竖井开挖工作甚巨,竖井开挖成败除了地质因素外,有效之止水灌浆工作亦为主要关键。雪山隧道竖井地址岩体破碎,地下水丰沛,3#竖井开工初期止水灌浆成效不如预期,致开挖工率远低于预定进度,经检讨评估后,排气井采水玻璃灌浆工法(Labile Wasserglass grouting)、进气井GL:-157.60以下采皂土水泥灌浆工法(Bentonite Cement grouting)降低开挖面侧壁之渗水量,辅以强制抽排水系统,得以顺利开挖。鉴于3#竖井皂土水泥灌浆成效良好,1#竖井止水亦采用皂土水泥灌浆工法,由实际开挖过程验证,皂土水泥灌浆工法可有效降低开挖面侧壁渗水量。针对水玻璃灌浆工法(Labile Wasserglass grouting)及皂土水泥灌浆工法(Bentonite Cement grouting)之成效,比较不同灌浆工法对竖井开挖工率之影响程度,期供后续竖井工程选择止水灌浆工法之参考。

The effective performance of grouting is an important keypoint for a successful shaft excavation. The rock condition of the ventilation shafts in Hsueshan tunnel are fractured and highly permeable with large amount of groundwater. In shaft No.3 , the performance of Bentonite Cement grouting in the intake-air shft is more efficient than Labile Wasserglass grouting in the exhauste-air shaft .Thus in shaft No.1 , Bentonite Cement grouting was proceeded through the whole shaft before excavation. As a matter of fact , the excavation of shaft No.1 makes extremely excellent progress.