Research conclusions：(1)Impact hole single cage pile expanding diameter mainly due to the impact force to impact into the hole，put flow sand in underground water level，gravel，silt，and soft plastic clay layer contact the bedrock，as well as the cavities within the filling fabric impact into the hole，respectively by the mud return hole with a hole，which is larger than the diameter of pile formed around the construction of underground space，underground space concrete large expanding diameter，the corresponding expanding appear above the necking and exposed reinforcement； (2)Impact hole single cage pile can be made in hard plastic silty clay layer that have not groundwater；(3)Percussion hole double cage pouting pile construction should be used in order to prevention of expanding diameter and expose reinforcement of the concrete and ensure the concrete quality of pile body integrity in the sand，gravel，silt flow layer that have groundwater；(4)Percussion hole double cage pouring pile should be applied and generalized in the field of percussion hole pouting pile．