公路隧道围岩现场快速分级方法研究

On-site rapid classification method of surrounding rock in highway tunnel

隧道围岩分级是正确地进行隧道设计与施工的基础,一个符合隧道工程实际情况的围岩分级对提高隧道掘进速度保证施工质量有着十分重要的意义。隧道在施工期间常出现揭露围岩状况与勘察期间给定围岩级别不符的情况,加之地质条件较为复杂,造成围岩级别变化很大,为了保证施工质量和施工进度,在施工过程中需要进一步的围岩级别变更,但是目前规范中所采用的分级方法需要进行室内试验,而现场却无法提供试验条件。因此,需要寻找一种基于现行《公路隧道设计规范》并且便于在现场实施的围岩快速准确的分级方法。文中以十天线明垭子隧道为工程背景,采用数字式点荷载试验、数码照相技术和围岩钻孔内窥试验为综合性现场测试试验手段对隧道围岩进行快速分级。实践证明,利用现场试验技术开展隧道围岩快速分级技术研究具有重要的工程应用价值。

Classification of tunnel surrounding rock is the basis of correct tunnel design and construction.The surrounding rock classification which corresponds to the actual condition of tunnel project has an important meaning for increasing the speed of tunneling and to ensure the quality of construction.It is quite normal to observe a disagreement between the surrounding rock exposure in the tunnel building and the given surrounding rock level during exploration period.On top of that,the complex geologic conditions may significantly vary the surrounding rock levels.To guarantee the both quality and progress of tunnel construction,it is required to further modify the surrounding rock levels.However,the existing standard classification methods require the indoor experiment.In addition,the on site experiment is not available.Hence,it is desirable to develop an on site method that is based on the current Code for Design of Road Tunnel and is capable to provide a rapid and accurate surrounding rock classification.Under the project context of sub tunnel of Ten-Day Mingyazi,this article rapidly classifies the tunnel surrounding rock with comprehensive field test measures such as digital point load test,digital photography and surrounding rock drilling endoscopic test.Practice has proved that the field test technologies for rapid classification of tunnel surrounding rock has important value in research on engineering application.