So in such a formation construction,it is important to use the technology of drilling mud back to tank to balance the pressure of the loose layer and prevent the borehole collapse.

With the restriction of construction technology,sediment at the tip of bored pile in slurry wall is difficult to be cleared,and soil there and aroud pile is disturbed easily,so the vertical bearing capacity of a single pile will be reduced to some extent.

In this article,authors introduce pile foundation drilling slurry used in Sutong Bridge,and mainly compare preparation and application of high quality PHP slurry with green SM slurry’s.