Abstract: Through tests and observations of 361 place-in-situ piles in a construction site in Wenzhou, five kinds of curves of grouting pressure (P) and grouting time (t) are drawn. The tests show that the longer the age of bored piles, the higher the opening pressure of pile end post grouting. However, the age of bored piles has little influence on the final grouting pressure. And there is positive correlation between the thickness of gravel layer with cohesive soils and grouting pressure. In the planar graph of pile arrangement, the grouting pressure of the piles in the center is larger than that of border piles. And the final grouting pressure of the piles in the late grouting order is larger. Static load tests on six piles with different grouting volumes show that there is a reasonable limit grouting volume for a single pile. When the grouting pressure is lower than the lower limit, the ultimate bearing capacity and settlement cannot meet the design requirements.