Reliability evaluation of filling material injection after pulling-out existing piles by pile-tip chucking system (PG method)

The pulling out of existing pile is one of the critical issues in recent years with the aging of infrastructures, and it is difficult to clarify that the construction has been completely carried out because it cannot be directly observed. In recent years, two types of a wire rope type and a chucking type have been generally applied for pulling out existing piles. The chucking type is developed as a new method of the pulling out method to overcome the issues of the wire rope type for which impossible to pull out the damaged pile and the filling material cannot be injected from the deepest part at the same time. However, the pulling out methods is a method based on the rule of thumb, and it is not shown that the filling material surely shows its enough strength. Therefore, this research finds grounds for establishing the pile tip chucking type existing pile pulling out method, and statistically analyze the test results of the filler material samples collected after the construction of the chucking type existing pile pulling out method. The reliability of the pulling out method was evaluated.