The Research Of Integrated Testing And Application Of Low Strain Reflected Wave Method

Presently, Low strain test method is representative and popular way of pile integrity testing. Detecting bearing capacity and integrity of the detection of the pile is the pile quality detection of the main content, this article introduces the pile integrity testing,according to the relevant regulations and relevant industry standards will pile testing can be divided into direct method, semi-direct and indirect. Low strain reflected wave of pile testing technique is one of semi-direct method, the pile low strain test pile integrity testing technology as a dynamic measurement technology, widely used in the detection of pile foundation engineering. Although the pile testing technology in recent decades has been history, but it is still a technology in the development of practicality, the theoretical knowledge and practical application of engineering deficiencies and limitations still exist.Theoretical foundation low strain stress wave reflection method is a one-dimensional linear elastic rod model. Industry standard defect related descriptions pile three main indicators:location, type and extent of the impact of which on the degree of defect classification pile integrity is the most important. Dynamic Method is detected, irrespective of the type of defects, which are the visual representation of the pile impedance mutations occur defects,smaller or larger, but also the impedance of the mutation may be the overall performance of any one or more defects superimposed. Pile Foundation Dynamic Testing Technology is a set of science and physics of vibration wave mechanics, dynamics, computer information technology, basic engineering and electronic signal processing various disciplines and an integrated technology, it is also a more complex subject. So far low strain reflected wave method there are still some unresolved issues in the practical application of engineering, so the detection technique needs to be further explored and improved, in order to get more accurate results.The article introduces the developing state and the strong and weak points of dynamic testing method for foundation piles and some quality problems easily occurred in common pile types at first. Then, the stress wave reflection wave in the pile body and the reflection at the interface of the defects are analyzed by using Midas/gts finite element analysis software. Three kinds of typical piles are simulated to investigate the variation of the pulse width and the change of the load. The influence of the time domain waveform is analyzed, and the method of detecting the defect types is summarized. In the end, the paper discusses the practical application of low strain reflected wave method, through the analysis and comparison of the practical and theoretical analysis, the validity and accuracy of this analysis is verified, which makes the low strain reflection technology more perfect.