Study Of Control Settlement After Construction Of Roadbed Over Soft Foundation And Overload Preloading

The most of soft foundation in our country is located in coastal, The Changjiang River delta and The Zhujiang River delta. Due to the deep soft foundation,s weak shearing strength, huge compression, low permeability and weak engineering mechanics properties, we encountered some serious problems about settlement, which directly influenced the stability and durability of structure engineering. Therefore, how to control the settlement of soft foundation effectually is a commonly-concerned issue in geotechnical engineering field. Beginning with the method of improving soft foundation, the measures are discussed to control the settlement, and how to control the settlement with overloading preloading.The components of settlement are analyzed by understanding the concretion mechanism of soft foundation. By comparing the methods of curve fitting based on field settlement, it concludes that selecting the prediction method of settlement after construction should be according to the construction condition, and the spot monitor should be strengthened.Controlling the settlement after construction is the key problem in highway constructions. By analyzing current state standards in permissible settlement after construction in our country, In addition to discussing the method of foundation treatment, the article puts forward to control settlement after construction by decreasing foundation constant load, improving roadbed condition crossed section in design, adopting reasonable method to fill and build, implementing dynamic state supervision.Owing to the overload designing are not as coincidence as practical. It carrys on excellently in the design of overload based on the existing data and make a feedback construct instance. At first, it should determine overload thickness with matching S～H relation, then determine unloading time according to the reasonable unload standard. In the meantime, how to decide the unload time is analyzed among the dissimilarity circumstance by adopting the method of settlement speed and settlement after construction.The disposal course is simulated about profundity soft foundation of beijing-zhuhai expressway guangzhou-zhuhai north section using finite element, which validates the feasibility of using the method of settlement speed to control unloading time.