浅埋双连拱隧道曲中墙应力计算方法及施工模拟研究

Research on Calculation Method of Stress and Construction Simulation for Curved Middle Wall of Shallow-buried Double-arch Tunnel

在双连拱隧道施工过程中,中隔墙的应力大小及其分布非常复杂。针对目前计算双连拱隧道中隔墙应力尚无成熟的理论的问题,基于规范及普氏压力拱理论,推导出了埋深H满足h_q<H<2.5h_q的浅埋双连拱隧道曲中墙应力的计算公式。并通过有限元模拟分析了苏州凤凰山浅埋大跨度双连拱隧道复杂施工过程中中隔墙应力的分布及变化规律,鉴于开挖完成后中隔墙监测剖面应力值与计算剖面应力值变化趋势极其相似,根据模拟结果对计算公式进行了修正。通过与应力实测数据及其他工程实例的对比分析,验证了所提出的曲中墙应力计算公式的合理性,可为类似工程从设计到施工提供参考。

In the construction process of double-arch tunnel, the magnitude and distribution of stress of middle wall is extremely complicated. Aiming at the problem that there is no mature theory to calculate the stress of double-arch tunnel, based on the code and the Protodyakonov＇s pressure-arch theory, the calculating formula which is applied to calculating the stress of shallow buried double-arch tunnel＇ s curved middle wall with the covering depth H form hq 〈 H 〈 2.5hq is deducted. Through the FEM method, the stress distribution and changing tendency of the middle wall under the complicated construction stages based on Phoenix Mountain large-span double-arch tunnel in Suzhou is analysed. In the light of the varia- tion tendency of stress value by monitoring is very similar to the calculated stress value, according to the simulation results, the formula is modified. Comparing the formula calculation consequences with the practical measured data and other project examples, the results indicate that the calculating fomula of the curved middle wall stress is reasonable, and it can provide reference from design to construction for simi- lar engineerings.