In the high-temperature and low-rainfall season,weakly expansive soil in railway subgrade is prone to shrink and consequently make subgrade deformation.Such deformation results in rapid and large changes in track geometry parameters.Using temperature,rainfall and track geometry measurement data,this paper firstly analyzed track deformation characteristics.Subsequently,a cumulative climate utility index was defined and expressed as formulas to quantify moisture change in subgrade.Base on the index,a model was proposed to estimate the onset date of track deformation.Using the temperature,rainfall,and track geometry measurement data for the years of 2016-2018 over a conventional rail track section having weakly expansive soil in subgrade,the proposed model was validated.The result shows that the estimated onset dates all match with the actual dates for all milepoints except 2 locations where ballast materials have been replaced.These findings indicate that the proposed model can accurately predict when track starts to deform under the effect of subgrade shrinkage resulting from weakly expansive soil,and therefore can reliably guide just-in-time track maintenance works.
维普
万方数据
