Study On Vacuum Transfer Law Of Vacuum Preloading

With the development of economic in the coastal areas in our country, land resources is increasingly tight, so produce land from sea and sea reclamation have become an important means of alleviate the shortage of land and promote economic development. In the early thirteenth century, Holland begins large-scale sea reclamation, now Holland has 8300 square kilometers made of artificial reclamation. Japan's land reclamation has more than 1600 square kilometers, including Kobe artificial island and Osaka International Airport. Our country begins to reclamation activities from the 50s and 60s of last century, to the end of the last century, coastal reclamation area are 12000 square kilometers, an annual average of 230 to 240 square kilometers of sea reclamation.Sea reclamation is mainly form through the mud hydraulic fill to the shore, the short-term drying and vacuum preloading treatment. Our country starts research the vacuum preloading method from the 50s and 60s of last century, to the early 80s and made breakthrough progress, has now been applied to large scale coastal each district actual engineering. In vacuum preloading, settlement and pore water pressure are having immanent inevitable connection. One is due to the new blow fill soil under owe consolidation state, the excess pore water pressure dissipation, the soil produces consolidation settlement. On the other hand is artificially applying a vacuum pressure leads to soil pore water pressure reduce, soil consolidation also occurred. Therefore, pore water pressure dissipation is the prime cause leading soil consolidation settlement. The current specification use settlement and pore water pressure as a vacuum unloading standard, account for pore water pressure is a key element in the vacuum preloading process, and has a great significance to guide the implementation of vacuum preloading. Therefore, the content of the thesis covers the following aspects:1. Briefly reviews the major common methods of dealing with soft soil.2. Through the vacuum preloading projects of the reclaimed soft foundation in Tianjin Dongjiang port, described the procession of construction of vacuum preloading , the field test of reinforced area and the implementation process.3. From the measured results, analyzed the changes of the groundwater level in the process of vacuum preloading .4. Analyzed the concepts of vacuum, negative pore water pressure and pore pressure and other basic concepts, the differences and similarities between them; focused on analyzing the relationship between vacuum and pore water pressure on the vacuum probe , vacuum transfer law in the process of vacuum preloading in unsaturated zone and pore water pressure distribution in the saturated zone, the excess pore water pressure in the soil before vacuum pumping.5. Concluded the characteristics of soil subsidence and the deep soil reinforcement effect in the process of vacuum preloading.