Study On Monitoring And Forecasting Method Of Subgrade Settlement Deformation In Xinjiang Section Of Lanzhou-Xinjiang High-speed Railway

In order to meet the needs of high-speed railway construction,the Ministry of Railways has promulgated a large number of technical specifications,the initial formation of the technical standards for passenger dedicated line.But high-speed rail construction of key technology research less for special geological conditions and natural environment and need further research.Besides the complex engineering geological,hydrological environment and the poor weather conditions in Xinjiang section of Lanzhou-Xinjiang High-speed Railway,the most of the road sections pass through the roadbed,and the roadbed is often the weak link of the settlement control,which makes the settlement control of the roadbed is very important.Moreover,the real-time monitoring and prediction of subgrade settlement is an important means to control settlement in the process of railway construction,so this paper relies on research projects on Xinjiang section of Lanzhou-Xinjiang High-speed Railway Company,China Railway Northwest Research Institute Co.,Ltd.and Southwest Jiaotong University,aiming at the special engineering geology and climatic conditions in Xinjiang section of Lanzhou-Xinjiang High-speed Railway,the monitoring and prediction of settlement deformation are studied.The main research contents and conclusions are as follows:(1)Through the actual survey and the meteorological data of Xinjiang Meteorological Bureau,the engineering geology and bad climatic conditions of Xinjiang section of Lanzhou-Xinjiang high-speed railway are introduced in detail,and the line is divided into five wind areas.The sedimentation deformation monitoring and prediction study is carried out with special geology(silt,saline soil,Gobi soil,etc.).(2)To ensure that the monitoring network accuracy and frequency to meet the regulatory requirements is to develop a reasonable monitoring program premise.At the same time,hot,cold,wind and other adverse weather conditions is the impact of Xinjiang segment in Lanzhou-Xinjiang high-speed railway monitoring network accuracy of the main factors.In this paper,the CDI-400 combined sedimentation instrument developed by China Railway Northwest Institute has carried out low temperature,high temperature test and field test to ensure the accuracy of the monitoring network.The results show that the CDI-400 combined settling instrument still has a high test accuracy at-20 ℃.The measurement accuracy is basically within ± 0.2mm.Under high temperature exposure conditions,the temperature of the instrument surface exceeds 50 ℃,but the CDI-400 combination and the measurement accuracy is basically within ± 0.2mm.The field test shows that the CDI-400 combined sedimentation instrument can meet the technical requirements of subsidence observation.(3)Select the representative work point(DK1338,DK1346,DK1680)for the settlement of the roadbed settlement analysis found that: for the silt road section,the use of CFG pile for foundation treatment,after 6 months of preloading,the total settlement of the roadbed and the foundation settlement of the embankment is basically stable.For the Gobi gravel soil section,the foundation treatment is carried out by impact rolling.After the preload is not taken,the total settlement of the roadbed is basically stable after 3 months of completion.(4)Combined with the measured values of the representative sections of the Xinjiang section of the Lanzhou-Xinjiang high-speed railway,this paper uses the hyperbolic method,the exponential curve method,the three-point method,the Asaoka method,the Poisson method and the GM(1,1)Prediction of Subgrade Settlement Deformation.The results show that the correlation coefficient between the exponential method and the Asaoka method is the highest and the error is small.The correlation coefficient between the predicted value and the measured value is relatively low,and the settlement data is larger Fluctuation and may lead directly to the hyperbolic method to predict the error or can not be fitted.The exponential method or the Asaoka method is the first choice method for the settlement of Xinjiang subgrade in the Lanzhou-Xinjiang high-speed railway,followed by the three-point method and the GM method.