Abstract:

The vertical shaft and horizontal adit of a mined tunnel of Shenyang Metro crosses underneath garbagepacked layer. Due to the complexity of the layer sources, the construction settlement can not be brought under effective control and the construction risk is high. In order to guarantee safe construction, the components of the packed layer are detected by means of supplementary investigation; the risk grade is increased and special design and construction are made. The settlement causes for vertical shaft are analyzed; the grouting reinforcement methods are compared; the permeable well method is carried out; and the vertical shaft floor is sealed. A series of technologies, including deep hold grouting, lowering the crown elevation, temporary lining and long and short duct, are adopted. Meanwhile, the settlement of the tunnel has been brought under effective control by means of monitoring and gas detection technology. The abovementioned technologies are proved to be rational and feasible according construction practice. 

Key words: Shenyang Metro, vertical shaft, horizontal adit, garbagepacked layer, deep hole grouting