关键词: 明挖隧道, 衬砌结构, 受力变形, 裂缝, 监测

Abstract: The lining structure is prone to cracks due to insufficient maintenance and early demoulding of the lining structure of large open-cut high-speed railway tunnel. In order to prevent the lining structure from affecting the waterproofing and structural safety of the tunnel during the operation period under the effect of dead weight stress, finite element analysis and site monitoring are carried out by setting bar gauges, concrete strain gauges, earth pressure gauges and surface strain gauges on arch shoulders and haunch of typical cross-section of lining structure of long-and-large opencut Donghuayuan Tunnel on Beijing-Zhangjiakou High-speed Railway. The analytical results show that: (1) The plastic strain is easier to occur on arch haunch than arch shoulder of lining structure, the cracks appear above the short side wall near the one-half cross-section and the arch line, and the cracks are circumferential ones. (2) For the concrete above the low side wall and below the arch line, the shrinkage deformation caused by the cooling will be restricted by the shear force of the low side wall steel bar, which would not lead to horizontal displacement. Finally, suggestions for controlling the deformation of the lining structure and shortening the construction schedule are provided.

Key words: open-cut tunnel, lining structure, stress deformation, crack, monitoring