Quick Pile Capacity Test High Strain Dynamic Tester

It is one of the main functions of high strain dynamic pile test method to determine whether the bearing capacity of single pile meets the design requirements. The bearing capacity of single pile depends on two factors: the bearing capacity of pile structure and the resistance of soil and soil to pile, which is usually controlled by the resistance of soil and soil to pile. Since the high strain cannot be used to quantitatively evaluate the bearing capacity of pile structure, it is not suitable to use the high strain method to determine the bearing capacity of single pile for the pile with serious defects (the bearing capacity of pile is likely to be controlled by the bearing capacity of pile structure).

The bearing capacity of single pile determined by high strain method refers to the resistance of rock and soil to pile stimulated in dynamic test pile. Only when sufficient relative displacement between pile and soil is generated, can the bearing capacity of pile be objectively evaluated. The relative displacement between pile and soil using high strain method still has a significant distance compared with the static load test. Therefore, the bearing capacity of single pile determined by it is generally lower than the ultimate load of single pile in static load test (which is safe in engineering), especially when the matching ability of hammer and pile is obviously insufficient, this contradiction is more prominent.

Strictly speaking, the high strain method is semi-empirical method and semi-direct method. Therefore, in the aspect of testing the vertical compressive bearing capacity of single pile, the high strain method uses the semi-quantitative and semi-qualitative wording of "judge" rather than the strictly quantitative wording of "confirm". In the same way, the "direct method" should be adopted for the bearing capacity test which provides the basis for the design, that is, the vertical compressive static load test of single pile.