管棚-箱涵工法中管棚合理间距分析

An Analysis of the Spacing Between Pipes in Pipe-Roof Box Culvert Construction Method

郑开快速通道采用管棚—箱涵工法施工,在箱涵土体开挖过程中,为了防止局部超挖引起的管棚上部土体向下挤出或者滑移,需要合理地控制管棚间距。文中首先分析管棚上部土体的"微拱效应",建立了微拱分析模型,通过对微拱模型的受力分析,给出了基于土体极限平衡条件的管棚容许间距计算方法,并以郑开线为实例进行验证,同时分析了土层参数、管棚直径等因素对管棚容许间距的影响,最后用有限元对"微拱效应"进行了模拟。

The pipe-roof box culvet construction method was adopted during the construction of the fast track between Zhengzhou and Kaifeng. In order to prevent the above soil from squeezing out between the pipes during sectional over-excavation,more attention should be paid to a rational spacing between pipes. In tiffs article, a micro soil arching model is established after an analysis of the micro soil arching effect in the soil above the pipes, then, a formula to calculate the allowable maximum spacing between the pipes is put forward based on Mohr-Coulomb failure criterion, and the formula is verified by the practical work of the fast track between Zhengzhou and Kaifeng, different factors which affect the allowable maximum spacing between pipes were analyzed, such as the parameters of soil, the diameter of the pipes and the friction coefficient between soil and pipes, at last, the micro soil arching effect is simulated by finite element method.