Abstract：
Based on the bench method used in the site construction of a tunnel on Lanzhou-Chongqing railway and the deformation that occurred, this paper analyzes the causes of work face collapse, deformation of surrounding rock at the back of the work face, and primary support and even "closing" collapse. It studies the key factors affecting deformation in terms of geology and construction during the bench construction and describes the relationship of bench height, length, and driving rate to the geological condition, parameters for the advance support of the tunnel. Some countermeasures are put forward.
2012, Vol. 49 