doi:10.3850/GI113

ABSTRACT

The drainage preloading method is often used in improving stability and decreasing settlement of soft clay foundation. The process of drainage preloading method used in improving soft clay of expressway subgrade includes the drainage bodies first constructed, and then classification preloading by embankment load; the pore-water is gradually dissipated, the soil is gradually consolidated, and the strength of soil is gradually improved. The calculation and forecasting of settlement is needed in whole construction process of expressway. Based on common expression of consolidation theory, inversion parameter of Asaoka method and the settlement speed expression on first-grade instantaneous load of homogeneous foundation, the settlement speed method is generalized in different preloading style, multilevel loading and multi-layered soil. The improved method is used in controlling speed of embankment construction, forecasting settlement after-construction, evaluating soft clay reinforcement effect and calculation of pre-flip height. The calculation and forecasting result based on improved settlement speed method is anastomosous with field settlement test data in loading, preloading, unloading and pavement structure layer construction period of Hangpu expressway.

Keywords: Expressway; soft clay foundation; consolidation; settlement rate; settlement after-construction.

© 2010 by Geotechnical Society of Singapore (GeoSS)