大跨度暗挖地铁车站开挖工序优化研究

青岛地区良好的地质条件为暗挖工法提供了广阔的应用背景,软土地层条件下难以实现的大跨度浅埋暗挖工法能够在硬岩环境中顺利开展。但随着工程经验的积累,发现传统的双侧壁导坑法及拱盖法在硬岩环境中仍存在优化空间。如何结合地质条件,简化工序成为设计施工的关键。笔者结合不同的地质环境,对施工工序进行优化设计,研究出适用于硬岩环境下的工法,根据工程经验总结阐述了双侧壁导坑法、拱盖法、拱部双侧壁+下部台阶法、初支拱盖法、台阶法等工法施工步序,并对各种工法工序特点、适用地层及其施工耗时进行对比。研究结果表明,优化后的初支拱盖法、能够适用于Ⅱ、Ⅲ及部分Ⅳ级围岩中,适用范围较广,且施工安全性较高,施工周期比双侧壁导坑法缩短了8~10个月,比优化之前的拱盖法缩短了4~6个月,优化后的拱盖法能够在青岛硬岩地层广泛应用。

Study on Optimizing Excavation Construction of Large Span Subway Station

Qingdao provides good geological conditions for tunneling construction to achieve large-span shallow mining,which is difficult for soft soil.With the accumulation of engineering experience,the traditional double-side-drift method and arch-cover method do not apply to hard rock environment perfectly.According to the actual situation,combining reasonable steps to simplify the construction method has become the key to optimize excavation construction.For different geological environment,on the ledge method to optimize the design,construction method developed was suitable for hard rock environments,based on engineering experience summary describes the double side drift method,arch cover method,arch double sidewalls + lower step method,the initial support ledge France,and other construction method step method steps.Finally,a variety of process engineering methods,suitable formation and construction were compared.The results show that the optimized dual arch sidewalls + lower step method,early support arch cover method,can be applied to Ⅱ,Ⅲ,Ⅳ grade surrounding rock,a wider scope and higher construction safety,construction cycle than double side drift method shortens the 6 to 10 months,compared with the previous ledge optimization method shortens the 2 to 4 months,after optimization the arch cover method can be widely used in hard rock formations Qingdao.