不同埋深下大直径盾构隧道横向刚度有效率

Lateral Equivalent Stiffness of Large Diameter Shield Tunnel Lining Structure at Various Buried Depths

摘要:

盾构隧道衬砌结构整体性能受到纵缝及环缝接头不连续性的影响，接头受力状态随埋深变化发生改变，其刚度也将发生变化，进而引起结构整体刚度的改变，对于大直径深埋盾构隧道这一影响更为突出.基于该问题，以上海沿江通道越江隧道典型衬砌结构为例，采用横向变形等效原则，参考管片接头结构试验结果，研究大直径盾构隧道横向等效刚度随埋深而变化的规律，并考察了地基刚度与错缝拼装对于计算结果的影响.结果表明，大直径盾构隧道的横向刚度有效率与埋深有较大关联，覆土较浅时变化规律相对复杂，覆土厚度超过1.0倍直径后随埋深整体上呈现先递增而后递减的趋势，在埋深达到2.0倍直径后由于地层成拱效应不再继续降低，上述规律还受到地层条件的影响.研究成果对于大直径盾构隧道的设计与计算具有一定的参考价值.

关键词:大直径盾构隧道; 横向有效刚度; 梁接头模型; 数值计算

Abstract:

The overall performance of shield tunnel lining structure is affected by the discontinuities of its longitudinal and circumferential joints. The load acting on the joints varies with the variation of buried depth of lining structure. As a result, the joint stiffness and the lateral equivalent stiffness of the overall structure also vary with the variation of buried depth, especially for large diameter shield tunnels. Taking the lining structure of Shanghai Yan Jiang Tunnel as an example, the lateral stiffness of large diameter shield tunnel lining structure at different buried depth was studied based on the lateral deformation equivalent principle and the structure test results of longitudinal joint. The influences of foundation stiffness and staggered assembling on the lateral stiffness were also studied. Numerical analyses reveal that the lateral stiffness of the structure is dependent on the buried depth. For the shallow buried tunnel, the lateral effective stiffness varies greatly. When the buried depth is greater than 1.0D (D is the tunnel diameter), the lateral effective stiffness first increases and then decreases with the increase of buried depth. When the buried depth is greater than 2.0D, the lateral effective stiffness stops decreasing because of the arching effect of the ground. In addition, the lateral effective stiffness is also influenced by the ground condition. The findings of this paper can serve as a reference for the design and analysis of large diameter shield tunnel lining structures.

Key words:large diameter shield tunnel; lateral effective stiffness; beam joint model; numerical calculation