关键词: 静载试验, 自平衡法, 荷载箱, 桩身完整性, 桩身断开面, 荷载箱处注浆

Abstract: 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.

Key words: static load testing, bi-directional load testing, embedded jack, pile integrity, pile fracture surface, embedded jack grouting