Abstract: The comparative studies on the large diameter, long bored piles in soft soils with and without post grouting are presented in this paper. Based on the instrumented static load test results on both types of piles, it is concluded that the post grouting can effectively improve interaction between pile and adjacent soils. Therefore, the capacity of both end bearing and side friction is obviously increased.

Key words: Long Bored Piles, Post Grouting, Pile Static Load Tests, Instrumented Pile Load Test