Passenger Line Of The Red Clay Of The Settlement Calculation And Prediction Methods

Since the whole line of Wuhan-Guangzhou passenger dedicated railway used ballastless track and its design speed is 200～350km/h, the high ride comfort and high stability is significant. Specifically, the requirement of post-construction in subgrade settlement is generally bellow 15mm and the demand of settlement for the bed length exceed 20m section is also severe, which should not exceed 30mm. As a result, the foundation deformation should be controlled severely. However, as a regional special soil which have special engineering and distribution characteristics, there are nearly 100km red clay distributed along the Wuhan-Guangzhou passenger dedicated railway. Therefore, whether the deformation for foundation of red clay satisfied the design requirement is the most important problem which design unit concerned. According to the research for settlement deformation of red clay foundation in the Wuhan-Guangzhou passenger dedicated railway, the most suitable method to calculate and predict the foundation settlement of red clay is derived. By calculating and predicting several work points , the verified basis for foundation design of red clay in the Wuhan-Guangzhou passenger dedicated railway has been provided, which is core part of this study.Based on in-situ plate loading test, and analyzing the results of field in-situ test, the empirical relationship between modulus of compressibility and in-situ modulus of deformation, the relationship between interior modulus of compressibility and static cone penetration test index and the relationship between interior modulus of compressibility and blow count of standard penetration test are summarized respectively. The value of red clay foundation for deformation modulus in each working point is statisticed and meanwhile the p～s curve of loading test is analyzed. The settlement of red clay foundation is calculated using the tangential modulus method which based on p～s curve of loading test, and its reliability is proved through computing the foundation settlement in several working points. According to existing settlement forecast model, the variable weight coefficient combination forecasting method and optimal combination forecasting method in forecast science are introduced in this paper, and the values of settlement in three working points of red clay foundation is predicted. By comparing with the monitoring dates, the method is valid and reliable. At last, the settlement of embankment for red clay foundation under step loading and load test are simulated by FLAC respectively using the deformation modulus which convert from interior modulus of compressibility. By comparing with the results of load test, it is found that the numerical simulation results and the load test is quite anastomosis,which indicate the empirical relationship between deformation modulus and compressibility modulus derived in this paper is reliable. Furthermore, the comparison among the settlement calculated by FLAC, the settlement of practical monitoring and the value of settlement prediction,illustrate that the method of calculating settlement and predicting settlement is valid and reliable.