Design Of Pile Sinking Vibration Detection Device

In the process of the pile driving,the vibration of the pile is mainly caused by the hammering force and soil,and is closely related to the safety and quality of pile driving.In the process of vibration,the sinkage of the pile after each hammering is called penetration,which can be used to evaluate the quality of pile,control the stopping hammer and optimize the performance of pile driving.The measurement of penetration is of great significance for piling works.However,due to technical and financial reasons,many domestic construction sites are still using the method of manual detection when detecting penetration,which has caused great hidden dangers to the safety and health of workers,and the reliability of the detected data is low.To this end,by analyzing the characteristics and status-quo of various penetration detection methods,this paper determines the research direction of extracting penetration from the vibration signal,and combines the user-operated hydraulic hammer to design a pile vibration detection device to achieve the function of detecting penetration and prompting to stop hammer.The main content of this paper includes the following parts:1.This paper proposes a detection scheme of vibration signal and builds the overall framework.Based on the dynamic analysis of the driven pile,combined with the hydraulic hammer equipment used by users,and from the perspective of the convenience of signal acquisition,this paper proposes an indirect detection scheme using the hammer frame as the vibration signal acquisition point.Finally,combined with the user’s needs,this paper divides the device into modules for designing.2.This paper makes a hardware and software design for each module.On the hardware,the device uses the STM32 chip as the main control module to control the data acquisition module to collect the vibration signal of the pile,and the signal is transmitted to the main control module for subsequent processing after the hardware processing to extract the effective penetration.Penetration is displayed via a LCD screen and then saved by the memory module.In the software,this paper establishes the connection between each hardware device and the main controller,designs a friendly man-machine interface through STem Win,shifts the Free RTOS as the core,and divides the starting task,the initial position setting task,the status display task,the watchdog task,the data acquisition task,the touch scanning task,the interface display task,the data processing task,the data display task and the data storage task according to the function.3.This paper completes the work of signal analysis.First of all,the signal acquisition experiment is completed in the construction site,and the vibration signal is analyzed to distinguish the distribution range of the useful signal,and the feasibility of the indirect detection scheme proposed in this paper is verified.Then,under the preset piling frequency of the pile driving and considering the real-time requirements of the detection device,this paper determines to adopt the analog filtering method to remove the high-frequency interference.Finally,this paper designs the processing method to calculate the effective penetration.Finally,the device completed the experiment.At a construction site in Guangzhou,the sensor of the detection device was installed on the user’s machine to test from two aspects: penetration detection and the prompt of stopping hammer.The test results prove that under the user’s accuracy requirements of 3mm,the accuracy of penetration detection can reach 95.86%,and when the penetration meets the stop hammer control standard,the device can give a stop prompt.The device meets the needs of users and improves the construction efficiency.