大尺寸矩形截面竖向曲线顶管顶进力研究

Jacking Force for Large Rectangular Section Vertical Curved Pipe Jacking

为了解决大尺寸矩形截面竖向曲线顶管在施工过程中顶进力的估算,针对曲线顶管分坡度掘进线路设计与实际施工分管节偏转的差异问题,对管节逐个进行受力分析,累积叠加得到顶进力的计算公式。首先根据顶管的起始点和终点之间的线路估算出竖向曲线顶管整体偏转角度,进而计算得到每个管节的偏转角度。针对顶管顶进过程中注浆压力与管节周围土压力之间的关系选择管节的受荷方式。当注浆压力大于围岩土压力时,选择注浆压力作为外荷载,反之选择围岩土压力作为外荷载。结果表明:通过对管节逐个建模,并考虑注浆压力与围岩压力之间的关系选择外荷载的形式得到的顶进力更能反映实际的顶管工作状态。同时计算结果还表明:影响顶进力的主要影响因素为土体重度、初始埋深和侧摩擦因数,同时,管节偏转角度对顶进力的影响不可忽略,并且随顶进距离的增大,影响程度逐步增强。

In order to solve the jacking force estimation of large rectangular section vertical curve pipe jacking during construction,aiming at the difference between the design and the actual construction of the pipe section deflection of the curve pipe jacking line,the force analysis of pipe joints was carried out one by one,and the calculation formula of jacking force was obtained by cumulative superposition.The deflection angle of vertical pipe jacking was estimated according to the line between the starting point and the end point,and then the deflection angle of each pipe section was calculated.According to the relation between grouting pressure and earth pressure around pipe joint during pipe jacking,the loading mode of pipe joint was selected.When the grouting pressure was greater than the soil pressure of surrounding rock,the grouting pressure was selected as the external load,and otherwise the soil pressure of surrounding rock was selected as the external load.The results show that the jacking force obtained by modeling pipe joints one by one and selecting the form of external load considering the relationship between grouting pressure and surrounding rock pressure can better reflect the actual working state of pipe jacking.The results also show that the main factors affecting the jacking force are soil weight,initial buried depth and side friction coefficient.At the same time,the influence of the deflection angle on the jacking force cannot be ignored,and the influence degree gradually increases with the increase of the jacking distance.