STUDY ON THE SETTLEMENT RATE STANDARD FOR DETERMINING THE SURCHARGE REMOVAL TIME FOR EMBANKMENT ON SOFT GROUND

Settlement rate method is often used to decide surcharge removal time for embankment on soft ground.Post-construction settlements controlled by empirical settlement rate standards used in some highways can not be obtained.A equation that describes the relationship between settlement rate during surcharge preloading and the post-construction settlements is derived by means of Terzaghi's consolidation theory for multistage loading.The settlement rate standards relevant to the allowed post-construction settlements are presented based on this equation.Numerical simulation analysis shows that the post-construction settlements controlled by the regional empirical settlement rate standards are much more less than the allowed values,the settlements controlled by the proposed settlement rate standards meet the requirement of specifications.Finally,one case history is analyzed to verify the use of the proposed standards.