饱和黄土地区高速铁路隧道施工关键问题处理与验证

Solutions and Verifications for Key Problems in Construction of Soggy Loess Tunnel on High-speed Railway

郑西客运专线张茅隧道黄土段位于地下水位线以下,存在开挖困难、初期支护沉降大、基底软化等问题,严重影响到施工安全、质量和运营安全。在动态设计中开展轻型动力触探、初期支护沉降对比、现场激振试验等,提出"快速封闭、集中引排、喷层早强、保护基底"的施工阶段防排水及基础施工原则。通过激振试验激振230×104次后,仰拱填充面的沉降稳定值小于或等于0·5mm等综合分析,得出隧道工后沉降能满足客运专线无砟轨道运营要求的结论。

As the loess section of Zhangmao Tunnel on Zhengzhou-Xi＇an passenger dedicated railway is under the phreatic line,there are the problems of difficult excavation,serious subsidence of the initial support,softened foundation.Therefore,they will have major impacts on the safety and function during the construction and operation.In the dynamic design,based on dynamic sounding,subsidence contrast of initial support and on-site vibration test,the principle of quick seal,concentrated drain,gunite premature strength,protection of foundation,has been put forward for foundation construction and drain.After the vibrating test of 2.3 million times of vibration,the last subsidence,which is less than or equal to 0.5 mm,of filling surface in inverted arch is reached.By general analysis of the subsidence,the conclusion has been reached that the post-construction subsidence is able to meet the requirement of operation on ballastless track of passenger dedicated railway.