Abstract:

The tunnel crossing underneath Zhongzhou Road in Zhengzhou is constructed by rectangular pipejacking. The thrusting force of the pipejacking is large due to its extralarge crosssection, shallow overburden, small spacing, long advancing distance and without using relaying chamber. In order to control the thrusting force effectively,the layout of grouting holes, preparation of thixotropic slurry, optimized design of grouting pipe and waxing of pipe surface are studied in detail. The results show that the drag reduction technologies used can achieve good effect.

Key words: extralarge crosssection, rectangular pipe jacking, grouting drag reduction, pipejacking thrusting force, thixotropic slurry