Research On Continuous Compaction Quality Monitoring System Of High-speed Railway Subgrade

The compaction quality of the high-speed railway subgrade is the foundation to ensure the comfortable and smooth operation of passenger trains,and it is also the key to ensuring the safe operation of passenger trains.Traditional high-speed railway subgrade compaction quality testing adopts the "sampling point" testing method.Sampling is not necessarily representative.It is also a post-work test,which cannot achieve real-time control of subgrade compaction quality.In addition,point-by-point inspection is time-consuming and laborious,causing obvious interference to the construction process,affecting construction progress,and difficult to adapt to the requirements of mechanized construction.To this end,the development of continuous testing equipment for subgrade compaction quality to realize the informatization and digitization of the construction process and testing process is an important means to ensure the construction period,quality,and management level of roadbed construction,and is of great significance to the entire railway project construction.This article analyzes in detail the current research status of high-speed railway subgrade compaction quality inspection at home and abroad,mainly from three aspects: conventional subgrade compaction quality testing methods and equipment,continuous testing methods and equipment,and indicators that characterize subgrade compaction performance;On this basis,it is proposed to use embedded technology,sensor technology and network technology to design subgrade continuous compaction detection equipment and continuous compaction data analysis system.According to the dynamic model of the principle of dynamic interaction between the subgrade soil and the vibratory roller,the relationship between the compaction performance of the compacted structure and the vibration acceleration signal detected by the vibrating wheel of the roller is analyzed,it is proposed to use the continuous compaction index CMV to characterize the compaction status of the roadbed,and the definition and calculation of the continuous compaction index CMV are analyzed in detail.The overall plan of continuous compaction quality inspection equipment for roadbed with STM32 as the core controller is designed.Completed the hardware system design of the entire equipment,including system power supply circuit design,signal conditioning circuit design,A/D conversion circuit design,GPS data acquisition circuit design,and GPRS data transmission module design,and the entire device was debugged to meet expectations aims.In view of the fact that when the least square method is used to establish the correlation between the conventional compaction index value and the continuous compaction index value,it is very susceptible to the influence of "outliers",it is proposed to use the Huber loss minimization that can achieve a good balance of effectiveness and robustness The learning method,compared with the traditional least squares method,can obtain the correlation between the conventional compaction indicators and continuous compaction indicators that reflect the real situation.Finally,the relevant calibration and function test of the continuous compaction quality inspection equipment for subgrade were completed through laboratory indoor tests,and the actual use on the construction site verified the stability,reliability and practicability of the continuous compaction quality inspection equipment for subgrade.