潮汐作用下的沉管隧道竖向位移计算

Vertical displacement calculation of immersed tube tunnel under tidal load

港珠澳大桥和深中通道工程中跨越深水航道部分均采用了沉管隧道的通过方式,传统理论分析往往将地基简化为多个互不联系的弹簧,忽略了土体的连续性,模型简单、参数少。考虑潮汐荷载影响,将沉管隧道管节等效为置于Vlasov双参数地基上的Timoshenko梁,以此推导了其竖向变形计算公式,并与Winkler地基上的Timoshenko梁计算模型进行对比分析以验证所提出的计算方法的合理性。以甬江沉管隧道工程为例,分析潮汐荷载影响下的沉管隧道管节接头竖向位移,将两种模型的理论计算结果与实测结果进行对比分析。研究结果表明,基于Vlasov双参数地基上的Timoshenko梁假设的简化模型能更好地描述沉管隧道管节接头竖向位移特征,与实测数据更吻合。该研究结果对沉管隧道的设计计算具有一定指导意义。

Immersed tube tunnel is adopted to cross the deepwater channel in both the Hong Kong-Zhuhai-Macao Bridge and the Shenzhen-Zhongshan Bridge.In traditional theoretical analysis,the foundation was usually simplified as a set of unrelated springs,the continuity of soil was ignored.The previous models were widely used in primary design calculation for its simplicity.In this paper,the cyclic effect of tidal load is considered,the pipes of the immersed tube tunnel are equivalent as Timoshenko beams placed on the Vlasov double-parameter foundation.Based on these assumptions,a calculating formula for vertical deformation of the immersed tube tunnel is derived,and then compared with the Timoshenko beam calculation model based on the Winkler foundation to verify the rationality of the proposed calculation method.Taking Yongjiang immersed tube tunnel project as an example,the vertical displacement of pipe joint in immersed tube tunnel under the influence of tidal load is analyzed,and the theoretical calculation results of the two models are compared with the field monitoring results.The results show that the proposed model based on the hypothesis of Vlasov double-parameter foundation can better describe the vertical displacement of pipe joint in immersed tunnel,which is more consistent with the monitoring data.The research results might have certain guiding significance for the design and calculation of immersed tunnel.