Numerical Simulation And Application Research Of Bridge Foundation Pile Detection By Elastic Wave Method In Southern Sichuan Intercity Railway

In the bridge foundation pile inspection project,the elastic wave method as a non-destructive inspection method has been widely used in practical engineering due to its advantages of simple equipment,high efficiency,low cost,and large area census.This paper analyzes the application of elastic wave method in the detection of foundation piles in the southern Sichuan intercity railway through a comprehensive study of field measurement engineering and finite element numerical simulation technology.The paper firstly expounds the theory of elastic wave method foundation pile detection.Taking the data collected on site as an example,the three processing methods and processing effects of waveform curves are studied.By introducing the common defect types in concrete cast-in-place piles and the elastic wave reflection law of different defects,it provides a reference for the subsequent interpretation of the measured waveform curve.By summarizing the judgment level and method of pile integrity,and analyzing the treatment measures of different grade piles,it can provide guidance for subsequent engineering inspection projects.In order to fully understand the situation of various defect curve types and provide a reference for the interpretation of actual waveform data,by using ABAQUS finite element numerical simulation software,a reasonable pile-soil model is established under the premise of referring to various parameters of the site pile.Several key steps such as the creation of the model in the numerical simulation,the simulation of the excitation load and the division of the grid are introduced,to ensure the success of the simulation,the model is optimized.By creating different pile diameters,different positions of the pile top receiving points and different models of soil around the pile,the impact on the simulation results is analyzed.Created models with typical catastrophic defects such as shrinkage,expansion and segregation appearing at different positions,different vertical dimensions and different lateral dimensions(or different concrete modulus sizes),as well as the overall tapering /expanding The change of the waveform curve of several gradual defect models such as reduction / gradual expansion.Finally,the selection of the equipment used in the site of the elastic pile method for pile inspection and its working principle are introduced.In order to ensure that effective data is collected on the site,the preparations that need to be done before the inspection are listed,such as the collection of site data and the treatment of the pile head.3.Setting of instrument parameters and installation of sensors.Finally,the selection of the equipment used in the site of the elastic pile method for pile inspection and its working principle are introduced.In order to ensure that effective data is collected on the site,the preparations that need to be done before the inspection are listed,such as the collection of site data and the treatment of the pile head,setting of instrument parameters and installation of sensors.By taking the data of the complete pile and several typical defective piles collected on the site of the southern Sichuan intercity railway foundation pile as an example,the curve change characteristics are analyzed,and combined with other verification data,the waveform curve is accurately interpreted,which is the actual work provide a certain theoretical basis and guiding significance.