Research And Application Of Shallow Vacuum Preloading To The Foundation Of New Reclamation At Central Fishing Port

With the economic development of Binhai New Area, land resources become a major bottleneck that restricted its development. Under condition of shortage of land resources and the high cost of land acquisition cases, using the BH New area's coastal beach land for the reclamation from sea is undoubtedly an effective messure. At the coastal beach of Binhai New Area there is mainly clay of the marine deposit composed by silt and silty soil. The new land mud of reclamation is of flow plastic, with a high moisture content, high void ratio, low permeability, and low strength. Therefore, it could not be further used for engineering purpose without treatment. In view of the fact that the fast development of Binhai New Area urgently needs land, there is for the new land soil no enough time to be sunned, its strength is therefore very low, it could not be direct used for construction by manpower and machine without treatment, it becomes an urgent problem how to treat the land so fast and ecnomically that it can be utilized just after the completion of the reclamation.On the basis of previous research, combined with the pilot projects of shallow foundation treatment at Tianjin Centre Fishing Port, the shallow filling vacuum preloading was put in practice in the areas of new reclamation; the technical problems encountered in the construction process were resolved effectively. It proved that the method we used can substantially reduce the construction cost on the basis of meeting the basic requirements of land use. So it is a new approach to obtaining the land effectually. In this paper following research work is included:1. The depth and spacing of plastic drainage plate were tested and their effects on ground treatment were studied in order to reduce the project cost as much as possible based on the determination of reasonable parameters.2. The foundation consolidation degree at different time was estimated using field data such as surface settlement, pore water pressure, water table, etc. and the full vacuum time was determined on the basis of meeting the engineering requirements after deeply analyzing the physical and mechanical parameters of reclamation soil.3. The construction technology of shallow vacuum preloading was analyzed. The direct draining was utilized; the water draining materials were used to replace the traditional sand cushion for the vacuum preloading. It proved a very feasible method in the region.4. The reinforcing mechanism of vacuum preloading was analyzed through the process of settlement, degree of consolidation, bearing capacity and others and many useful conclutions were obtained.