There are many differences in the standards of bi-directional load testing

among Chinese (JGJ/T 403-2017)

American (ASTM D8169/D8169M-18)

and European (ISO 22477-1:2018) standards

on the loading system

the displacement measuring system

the displacement convergence criterion

and the loading termination conditions. The layout of hydraulic tubing in the embedded jack in the American and European standards are significantly different from the Chinese standard. The displacement convergence criterion of the Chinese standard is more rigorous than the American and European standards. For pile integrity testing

the anomaly near the embedded jack shall not be directly judged as defect. Model testing of annulus embedded jacks were carried out. It shows that the position of the fracture surface in the tested pile is at the lower edge of the cylinder

and the concrete near the embedded jack would not be locally crushed. Field testing of double layer embedded jacks were conducted. It reveals that the soil filling rate of the fracture surface in the test pile is 50%-60%. Grouting process of the embedded jack after-testing is suggested. When grouting as required

the working pile can be used normally.