Study On Settlement Character Of High-speed Railway Subgrade During Operation Period

After the construction of Qin-Shen passenger special line since1999, building ofhigh-speed railway in Chinese mainland come into a booming period. High speedrailway has high stability and high smoothness requirements on the track structure, trackstructure has a limited adjustment ability. If the settlement exceeds the regulating capacity, itwill cause great damage to track-subgrade system, furthermore, reparing of ballastless track isincomparable difficult than ballasted track. Therefore, the settlement of subgrade plays acritical role in the safe and comfort quality and operating costs of high-speed railway.On the basis of Wuhan Guangzhou high speed railway science and technolegy project ofWuhan railway station. we did a series of subgrade settlement observation in some selectedrepresentative sections of the Wuhan Guangzhou high speed railway K1300+853channel.Then, a series of analysis was carried out according to the observation date. Mainly include:(1) Combined with the previous studies, the mechanism of high speed railway subgradesettlement was briefly analized and the settlement was briefly divided according to theproperties of soil deformation and subgrade deformation law.(2) A series of settlement observation was carried out in selected sections from. Based onthe observation settlement data, we did a series classification analysis discussing differencesof settlement regularity between cutting section, embankment, transition section, road-bridgetransiton section, road-culvert transiton section, line segment and curved line, inside andoutside the center of the line. Selected several kinds of commonly used curve fitting methodsand introduced the Boltzmann model to simulate and analyze the field settlement data, then,discussed the applicable condition of these methods and feasibility of these methods beingapplied to predict the subsidence trend. Some conclusions was introduced here: the settlementof the embankment, cutting section, bridge subgrade transition section are not the same; thesettlement of the side of the center line is larger than the opposite side; the settlement ofthe superelevation side in curve segment is larger than opposite side.(3) Based on the rheological theory, we improved the Kelvin model to make it suitablefor the analysis of strain-stress relationship under dynamic load. Then, we did analysises andpredictions of the settlement of No.21section of the embankment using the derived results.The last measure value of settlement was6mm, and the value of the computing model was4.5mm, and it forecasted that the settlement value would reach4.6mm3years later.Theresults show that the model is of good applicability, and can be used to predict thesettlementtrend;(4) Calculated and analyzed the cumulative plastic deformation of No.21section using the soil cumulative plastic deformation calculation model had been introduced by Li&Selig;the last measure value of settlement was6mm, and the value of the computing model was4.3mm, and it forecasted that the settlement value would reach4.9mm3years later. theresults show that the model is applicable for settlement calculation, and can be used to predictthe trend of settlement. Finally, combined with the curve fitting results and these two modelswe did a comprehensive comparison.