Abstract:

During the construction of Line 1 of Shijiazhuang Metro, rotary drilling bored piles are constructed with the assistance of polymer slurry. In the paper, the construction of the bored piles with the assistance of polymer slurry, including the polymer slurry preparation, borehole drilling, rebar cage hoisting, borehole clearing and concrete pouring, are presented, with the construction of the bored piles in Shijiazhuang as example. Furthermore, comparison and contrast is made between polymer slurry and bentonite slurry in terms of borehole quality, sediment thickness, borehole wall protection strength and environment protection. Conclusion is drawn that satisfactory construction quality and construction effect can be achieved when polymer slurry is used to protect the borehole wall.

Key words: borehole wall protection material, rotary drilling bored pile, Shijiazhuang Metro, chemical polymer, bentonite