Study On Effects Of Embankment Pre-setting Height On Post-construction Settlement For Soil Foundation Of Highway

The engieering improved that the presetting flip-height was an effective method to compensate post-construction settlement. The paper discusses it initially by analyzing factual measured data, calculating and laboratory experiment etc.Firstly in this paper a new model was set up to forecast post-construction settlement on the basis of the embankment fill thickness and the factual measured settlement data; Besides we analyze the physical meaning of this model and push over the expressing to calculate the amount of the presetting flip-height with different soft foundation depth and different time at which pavement elevation equals design elevation.Secondly simplified secondary compression model is found by one dimension compression in-door experiment of remolded clay. In this paper, on the base of secondary compression experiments of remolded soft soil secondary compression character was studied under overbading-unloading and reloading. It was found that Reloading process contained primary consolidation no matter what reloading pressure was, and primary consolidation time was over seemly and advanced before than the first compression. Second consolidation coefficient was not related to time, and became larger as reloading pressure increased larger and became less with pre- consolidation pressure. Regular relationships between secondary compression strain and over pressure ratio could be simulated by simplified hyperbolic model and the model parameters could be contained by the fitted line. Based on the model secondary compression settlement formula was established, which reflected the influence of soft soil character, pre-consolidation pressure and reloading pressure and secondary compression tended to one stable value with time. Compared between calculation value of the engineering example and post-construction measured data, the results were reliable by the secondary compression settlement formula in the paper, more reasonable than the traditional calculation methods.Study the presetting flip-height affects primary consolidation post-construction and secondary compression post-construction of soft foundation. Secondary compression post-construction is calculated by Yin zongze professor's method and modified and simplified secondary compression model on the condition of the different presetting flip-height respectively. Results indicate the presetting flip-height has a limited effect on secondary compression post-construction of soft foundation. Primary consolidation post-construction of the underlying soft layers is calculated by CSRG program. Primary consolidation post-construction of the underlying soft layers becomes larger with the increase of the presetting flip-height. Primary consolidation post-construction increases 1.7 centimeters when the presetting flip-height increases 5 centimeters. The effect on primary consolidation post-construction of the underlying soft layers is ill defined, but much more sensitive than secondary compression post-construction, that is an order of magnitude.Lastly introduce the application of the presetting flip-height, which are linkage segments between two conjoint different characteristic soil foundations, between soft soil and un-soft soil, between soft soil and bridge, and between two conjoint bridges.