Study On The PDA's Results Influenced By The Sensor's Place And Soil Piston

Basing on CAPWAP_C Method, this research adopts modified cell counting method to deduce F and v fitting formula of high-strain pile driving, from which sensor is in 4 units, without considering soil plugging effect. According to the deduced formula, an F and v fitting procedure is established when force wave and velocity wave are used as boundary conditions separately, and further F and Zv figures are drawn for certain position of sensor. The fitting result indicates that the modified approach shares a similar curve with the former in the first pile body unit, and gains an improved high-strain curve over the former approach in the second unit, which is more suitable for actual engineer project.As pipe pile is generally used in pile foundation in recent projects, this paper takes into account soil plugging effect here and adopts linear elastical method to deduce F and v fitting formula when a sensor is in 4 units from pile top. The result indicates that when considering soil plugging effect, monitoring curve of high-strain pile driving is close in shape to that without considering, but more precision.Finally, after briefly introducing its static loading analysis, an actual project is taken as an example to compare the measured curve and fitting curve deduced from this paper. The result demonstrates that the new approach is suitable to apply in real engineer projects, because the fitting detecting method of high-strain pile driving can be used to calculate ultimate load capacity of steel pipe pile. It also indicates that the fitting method which takes into account soil plugging effect offers closer result to measured data than that without considering...