Experimental Study On Vibration Response And Propagation Characteristic Of Roadbed Under High Speed Train

With the high-speed train speeds continuing to improve, as well as high-speed rail extending on various soft foundation such as saturated soft clay and loose sand, the train cycle dynamic load leads the foundation to a more and more impressive additional settlement after the opening of the high speed train. Thus a large number of geotechnical engineering and soil dynamics problems have become apparent. However, the domestic new high-speed railway lacks corresponding measured data for relevant research and analysis. In response to this situation, the author conducts a field test of the subgrade vibration relying on the beijing-tianjin intercity realway which top speed up to350km/h and collects data on the dynamic response generated by the high-speed train traveling at various speeds on the roadbed, and makes an experimental study of the vibration response of the propagation characteristics accordingly:In the Beijing-Tianjin Intercity Railway JJK86+274roadbed sectional field test, this paper makes vibration tests on total41high speed trains with speed distribution from113km to344km, and acquires410sets of experimental data from10speed sensors on the6testing points distributed from the Subgrade edge to the center of the track plate.Based on data collected in the field vibration test, the author plots the vibration waveform graph with the vibration response elements including vibration velocity, vibration acceleration and vibration displacement, and analyzes its vibration response characteristics. This paper also gives analysis of the frequency-domain characteristics and tests of the periodical vibration data, which determine the periodic vibration energy concentrated band. It analyzes the effect of train speed on subgrade vibration response in a scatter plot fitting way, statistics the change and development of each measured point vibration elements eigenvalue under different train speeds.This paper studies the subgrade vibration transmission characteristics, draws out a vibration transmission graph under different spreading situation, analyzes its characteristics and developing trends and compares the changes under different speeds. Through studying the characteristics of Vibration frequency domain in communication process, this paper gives analysis of the changes and developments law of the vibration energy and main frequency in the dissemination process under different train speeds.This paper makes a two-dimensional FEM model of the test embankment cross-sector with the ABAQUS analysis software, which loads the test data. Numerical simulation results and experimental results were compared to determine the accuracy and reasonableness of numerical simulation. On this basis, this paper also makes a further study on the vibration space distribution characteristics, the time response characteristics of the vibration element, the vibration transmission characteristics and the dynamic stress in-depth distribution rule, which obtains reasonable resultsThis paper has found the dynamic response process and eigenvalue of China’s high-speed train rail roadbed and its propagation and attenuation form in the roadbed. Provide technical reference for the country’s high speed railway future design and construction, and provide experimental basis for high speed railway roadbed deformation control and prediction caused by long-term operation.