Design And Realization Of Wireless Low Strain Pile Integrity Analyzer

With the continuous development of national economy and the increasing investment in infrastructure,the foundation pile project also develops rapidly.Because the foundation pile is buried deep in the ground and the construction process is complicated,some problems that are not easy to detect often occur,such as the expansion and contraction of the neck of the cast-in-place pile,and the broken pile,segregation and seam caused by improper manual operation.Foundation pile is an important part of bearing building,its quality is related to the whole safety of building.So it’s very important to detect the quality of foundation pile accurately and effectively.Wire equipment is often used in traditional foundation pile detection,which is heavy,complicated and costs manpower and material resources.Based on the above analysis,a new wireless low strain foundation pile integrity detector is designed in this paper.The main research contents are as follows:(1)Hardware design and development.Optimize the design of hardware circuit of pile detector,and introducing the WIFI module to solve the problem of low detection efficiency caused by the cooperation of multiple people in the traditional foundation pile detector.The wireless low strain foundation pile integrity detector designed in this paper is mainly divided into excitation vibration source,sensor,acquisition device and receiving device.The vibration source and sensor are mainly selected according to the design requirements.The design focuses on the acquisition device.In order to facilitate the design and debugging,it is divided into four parts: analog,digital,power supply and acquisition program.The analog part includes amplification,filtering and AD conversion module.Its main function is to amplify and filter the analog signals collected by the acceleration sensor,and then convert them into digital signals in the AD module and hand them to the microcontroller for processing.The digital part mainly includes the microcontroller,the bus driver module and the network wireless module.The microcontroller displays and processes the received signals sent by the serial port wireless module to the top computer.The power supply mainly includes the constant current source module and the power management module,in which the constant current source module provides constant current to the acceleration sensor,and the power management module is composed of two DC-DC modules and the low-voltage differential linear voltage regulator to provide working voltage to the system.(2)Detection signal denoising research.Found in the process of instrument use,some signal cannot be a good characterization of pile body characteristics,especially the environment around the presence of Noise,signal denoising problem in-depth research,introduced a Complete set of Adaptive white Noise Empirical Mode Decomposition(CEEMDAN,Complete the Ensemble Empirical Mode Decomposition with the Adaptive Noise)combined with wavelet threshold denoising algorithm,the acquisition of low strain reflection signal denoising processing.First to CEEMDAN decomposition of the signal,will be collected to the signal is decomposed into n Intrinsic Mode components(the Intrinsic Mode Function,the IMF),and then these signals with the original correlation calculation,choose the correlation between small component do wavelet threshold denoising,finally after the wavelet threshold denoising signal and the correlation of modal component refactoring,get the final signal denoising.The experimental results show that the proposed algorithm can effectively eliminate high-frequency noise and baseline drift noise,and the average SNR is 20.181 and the mean square error MSE is 2.245.Combined with theoretical analysis and field verification,the pile detector designed in this paper is small,portable,simple to operate,and can meet the detection requirements in complex environment,with practical application value and good application prospect.