大直径砼顶管的管道受力特性分析

Analysis on Performance of Large Diameter Concrete Jacking Pipe

为优化现有的顶管管道受力模式及其设计方法,结合上海市污水治理南线工程,采用数值模拟方法,对内径4 m的大直径钢筋混凝土顶管管道的受力特性进行了分析,研究了施工过程中管土接触压力的变化及顶管覆土厚度对管道外土压力的影响,比较了管道受力分布与《给水排水工程顶管技术规程》的区别,并分析了管道内力的差异.计算结果表明:土拱效应随覆土厚度的增加逐渐增强,管土接触压力分布比较平均,侧向土压力采用主动土压力计算偏于保守,地基反力也可适当均匀化,并且在此基础上的管道弯矩减小,轴力相应增大.因此,管道设计可以进一步优化,使工程更加经济.

The load model and its design method of a pipe are to be improved.Based on the South Line project of sewage treatment in Shanghai,the performance of inner diameter of 4 m jacking pipe was studied by numerical simulation.The variation of contact pressure between pipe and soil during construction was analyzed,and the influence of covering soil depth was then discussed.The differences of the load model from ＂the technical specification for pipe jacking of water supply and sewerage engineering＂ were researched,and the differences of the internal forces were compared.The results show that soil arch effect is strengthened with increasing of cover soil depth,while the distribution of contact pressure is more uniform than the codes.Therefore,the active earth pressure is conservative to calculate lateral pressure,and the subgrade reaction could be also more uniformed.The bending moment of pipe will decrease while the axis force increase if the load model is improved,which would optimize the design method of pipe.