Study of Deformation Control and Rule of Tunnel which Passes Underneath the Existing Tunnel in Underground Excavation of Subway Station

Jianchen Wang, Yunliang Liu, Dingli Zhang, Haiwei Bai, Xiaokai Niu

Abstract


Olympic Park Station of Beijing metro line 15 parallel closely crosses the existing large tunnel. Such a long distance to cross the existing tunnel, which is the first time in China. In order to control the deformation of existing tunnel, the monolayer pilot-tunneling pre-support pillar method is proposed. In this paper, the existing tunnel’s deformations which induced by the new method and the traditional PBA method are compared by the numerical simulation method, and the existing tunnel’s deformation low which is determined according to the measured value is analysed. Research shows that: (1) monolayer pilot-tunneling pre-support pillar method has advantages in controlling the deformation of the existing tunnel, decreasing the settlement of the ground and existing tunnel by dewatering and protecting groundwater resource. Compared with PBA method, the maximum deformation of existing tunnel is decreased by 36.5% after adoption of remove lower pilot tunnels and Forming a pile foundation underpinning system measures. (2) The deformation of the existing tunnel is mainly based on the cross section, and the measured maximum settlement is 42.2mm.

Keywords


Crossing engineering; existing tunnel; control measure; deformation law


DOI
10.12783/dtmse/ictim2017/9956

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