顶管施工中管道受力性能的现场试验研究

Site-based experimental study on pipe behavior during pipe jacking

对顶进过程中管道纵向与环向钢筋应力及管土接触压力进行了现场测试。实测数据分析表明,管节开始顶进时轴力随顶进距离增大而增大,顶进到一定距离后,基本维持在一定范围内。管顶和管底的内侧钢筋受拉,外侧钢筋受压;管节两侧的内侧钢筋受压,外侧受拉。钢筋混凝土管道可看作柔性管道。环向钢筋受力很小,但变动较大。管土接触压力随管道的顶进一开始缓慢上升,到一定距离后基本保持在一定范围内。注浆对管顶接触压力影响较大,注浆后压力明显减小,可取为上覆土重;对左右两侧接触压力影响较小。注浆前左右两侧跟管顶压力相差不大,注浆后则要明显大于管顶压力。

Vertical and annular reinforcing steel bar stress and pipe-soil contact pressure during pipe jacking were monitored on the spot. Field data were analyzed. It showed that axis force increased along with pipe jacking at the very start, and it maintained stated basically when jacking to a certain distance. When inner side reinforcing steel bar of tip and bottom pipe were pulled, outer side were pressed. And both sides of pipe were just contrary. Reinforced concrete pipe could be regarded as flexible pipe. Annular reinforcing steel bar bears very little but with great alteration. Pipe-soil contact pressure increased slowly along with pipe jacking, and it also maintained stated basically after some distance. Contact pressure of tip pipe was greatly affected by grouting. The pressure decreased obviously after grouting and it could be adopted as up-earth gravity. Contact pressures of both sides were affected less. Compared with the tip pipe, they were almost the same before grouting and noticeably bigger after grouting.