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.

Effect of slurry on bearing performance of bored piles;

A brief exposition to some problems concerning soil exchange, guide wall selection and slurry wall-protection to which attentions shall be paid during diaphragm retaining wall trench construction and understandings are offered.

The paper explores the construction technique and quality control of slurry to protect drilled bores for large diameter bored cast in place piles from the viewpoint of boring equipment, slurry mix ratio, placing of sleeves, operational technology and other important issues.