| High-speed railway subgrade compaction is an important part of high-speed railway construction,which is directly related to its long-term service life.Traditional roadbed testing methods are mostly point detection,and measuring multiple indicators is time-consuming and laborious.As a developing technology,continuous compaction system can evaluate compaction quality based on the response of vibrating drum during vibratory compaction,and adjust the working parameters of the roller based on compaction quality feedback.Based on the field test data of the Beijing-Xiongan High-speed Railway foundation construction,this paper analyzed the time-domain and frequency-domain characteristics of the vibrating drum acceleration and the change law of the traditional compaction indicators after each vibratory compaction,established a multi-body dynamic model of roller-soil system,and verified the effectiveness of the model.Based on this dynamic model,the effects of different excitation force amplitude,excitation frequency and soil strength on the vibrating drum response such as the vibrating drum amplitude and drum-soil contact force were analyzed.（1）Based on the field test data,the change law of the dynamic deformability modulus Evd,the bedding value K30and the shear wave velocity after each compaction were analyzed,and the characteristics of the vibrating drum acceleration in the time-domain and frequency-domain were analyzed,the correlation and difference between the compaction meter value CMV and the dynamic deformability modulus Evd were compared and analyzed,and the feasibility of continuous compaction indicators was verified.（2）A lumped parameter model of the roller-soil coupling system was established.According to the soil deformation and the drum-soil interaction relationship,the model was divided into three stages to establish dynamic equations,which were elastoplastic stage,elastic stage and separation stage.The dynamic equations of the model were solved iteratively using Runge-Kutta method.By comparing the time-domain and frequency-domain characteristics of the vibrating drum acceleration calculated by the model and the measured drum acceleration,the effectiveness of the lumped parameter model was verified.（3）According to the frequency-domain characteristics of the acceleration of the vibrating drum,the vibration state of the drum was divided into three forms:linear vibration,periodic separation and double periodic vibration（double jump）.Based on the lumped parameter model,the vibration state of the drum under different excitation force amplitudes and excitation force frequencies was studied.The linear boundary of the vibration state of the drum was proposed,and the variation rule of the boundary under different soil strength was studied.（4）Based on the lumped parameter model,the effects of different excitation force amplitudes,excitation frequencies and soil strength on continuous compaction indicators such as CMV and OMEGA are studied,and the independence and applicable conditions of common continuous compaction indicators are studied from a theoretical perspective.The advantages and disadvantages of common continuous compaction indicators are compared and analyzed,and some suggestions are provided for the subsequent research and selection of continuous compaction indexes.The research conclusions of this paper can deepen the understanding of the dynamic response of the vibrating drum in vibratory compaction.The division of the three vibration states of the drum can provide a basis for the feedback control of the vibratory compaction process.The analysis results based on the lumped parameter model provide a reference for the application conditions and advantages and disadvantages of the continuous compaction indicators such as CMV and OMEGA. |
