大尺寸矩形截面竖向曲线顶管顶进力估算:基于整体位移控制有限单元模型

Estimation of jacking force in large rectangular section vertical curve pipe:a global displacement control finite element

针对大尺寸矩形截面竖向曲线顶管顶进力估算,建立整体位移控制有限单元分析模型,得出顶进力与顶进距离之间的拟合关系。与分段位移控制有限单元分析模型相比,无需进行顶进力、侧阻力和端阻力的叠加,区段与区段之间的力学联系自然存在,同时考虑了管节转动对顶进力的影响,计算过程更加简便,计算精度更高。计算结果表明:相同条件下,整体位移控制有限单元分析模型估算得到的顶管顶进力大于分段位移控制有限单元分析模型,当侧摩擦系数为0.20、0.38时,整个拟合区段,前者顶进力均大于后者;当侧摩擦系数为0.30时,中前区段(顶进距离≤30 m)前者顶进力大于后者,中后区段(顶进距离>30 m)前者顶进力小于后者。说明管节转动角度对顶进力的影响不可忽略,且整体位移控制有限单元法对曲线顶管顶进力估算效果较好。对于一定尺寸和埋深的竖向曲线顶管,影响大尺寸竖向曲线顶管顶进力的主要因素为顶管与围岩之间的注浆压力大小、分布范围、竖向曲线顶管管节在轴向转折处的转动角度。

To estimate the jacking force in large rectangular section vertical curve pipe,a finite element analysis model of global movement control was established,and the fitting relationship between jacking force and jacking distance was obtained.In comparison to a finite element analysis model utilizing piecewise displacement control,our approach eliminates the need for superimposing jacking force,side resistance,and end resistance,thereby allowing for a natural mechanical connection between pipe sections.Furthermore,we accounted for the impact of pipe joint rotation on the jacking force,resulting in a simpler and more accurate calculation process.Our findings reveal that,under similar conditions,the jacking force estimated with the global displacement control finite element analysis model surpasses that derived from the piecewise displacement control finite element analysis model.When considering different side friction coefficients of 0.20 and 0.38,it was observed that the former exhibits greater jacking force than the latter throughout the entire fitting section.Specifically,with a side friction coefficient of 0.30,the former demonstrates higher values than the latter in the middle and front sections(jacking distance≤30 m),while displaying lower values in the middle and rear sections(jacking distance>30 m).This highlights the significance of accounting for joint rotation angle's influence on jacking force,emphasizing the superiority of the global displacement control finite element method in estimating curved pipe jacking forces.For vertical pipe jacking operations involving specific dimensions and burial depths,pivotal factors influencing jacking force include the size and distribution range of grouting pressure between the pipe jacking system and surrounding rock,as well as the rotational angle of the vertical pipe joint at the axial turning point.