복층터널 중간슬래브 유지관리에 따른 응력분포 특성 분석 Characteristics of Middle Slab Stresses in Double-Deck Tunnel During Maintenance
pp.47-56
PURPOSES : The purpose of this study is to investigate the stresses of the middle slab in a double-deck tunnel owing to the slab lift to replace the underlying elastic pads during maintenance workMETHODS: The middle slab was divided into three different sections: typical section, expansion joint section, and emergency passageway section. Finite element analysis models of these three sections of middle slab were developed, and the stress distribution and maximum stresses were obtained using the models when the middle slab was lifted to replace the underlying elastic pads. Various slab lifting methods were examined in this study such as one-, two-, and multiple-point lifts, distributed lifts, and one or both slab side edge lifts.RESULTS: When the slab side edge is lifted, the longitudinal stresses of the slab are almost the same as the principal stresses. This implies that the governing stresses are the longitudinal stresses. The maximum stresses with both-edge lifts are generally smaller than those with one-edge lifts at all three sections of middle slab.CONCLUSIONS: If the middle slab in a double-deck tunnel is lifted for maintenance, the slab should be lifted at multiple points along the longitudinal direction to reduce the tensile stresses.