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.

Based on the mechanic properties of slurry in drill holes it is suggested that the velocity of shear wave(Vs)can directly measured in a slurry filled drill hole without the tools such as the ball and the bar.

In this article, authors introduce that the construction quality of bored perfusion pile, which is made with mud protection and on the loess soil in Xi an district, influences such performances of the pile as bearing ability, deformation, axial force transference along pile body and side resistance realization.

The better economic efficiency was obtained by selecting mud protection with better expansive soil and additive.

Combined with project example,it analyzes the reasons generating mud protection wall drilled caisson pile slumping from the aspects of specific weight shortage of mud,moving load around pile pore,bad construction method etc,and introduces the accident treatment scheme from four aspects and the construction technical measures,which gets good effectiveness.

Executing technology is an important factor effecting load - bearing capacity of bored grouting pile with mud dado.