Field Experiment And Designing Theory Of Vacuum Preloading

Alongside the development of economy, there are more and more engineering constructions on soft clay ground, thus the techniques for ground treatment are becoming manifold day by day. During the process of engineering practice, a number of new and practical techniques has been used, among which, the method of vacuum preloading is quite common and new, it has been extensively used in recent years, and obtained both considerable engineering and economic results. However, this method has been still rarely applied and studied on the soft clay ground which is thick and deep, and the designing theory is still far from perfect, therefore, it is necessary to have a study on it combined with engineering practice.On the basis of the developing history and current research condition of vacuum preloading, as well as in combination with the project sample study and on-the-spot testing of three sewage treatment plants in Taizhou Zhejiang province which adopt the method of vacuum preloading to consolidate the soft clay ground that is thick and deep. A systematic conclusion has been carried out of the consolidation area, the number of vacuum pump, ground settlement, consolidation degree, water pressure of porosity, lateral displacement and variation principle of underground water level. The on-the-spot test shows that the effect of vacuum preloading was quite obvious to decrease the ground settlement during the process of consolidation of the soft clay ground which is thick and deep.Secondly, the mechanism of vacuum preloading has been analyzed. Through a comparative analysis with that of heaped preloading, it is pointed out that these two techniques are basically different. Therefore, the designing theory of heaped preloading can't be simply taken to conduct the design of vacuum preloading.Finally, on the basis of analysis findings above, the designing procedure of vacuum preloading has been concluded, some preferential designing methods based on the previous experiences and practice have been proposed, meanwhile, suggestions for the future search has been put forward.