Reclamation Large Shoals Of Silt Ground Vacuum-pressure Treatment Pretest Research Techniques

Now, land resources is getting more limited in the coastal areas of China, through theartificial reclaimed tidal marsh mud for reclamation has become an effective means to solve theproblem of land resources shortage. The ultra-soft soil formed by newly hydraulic mud fill willneed to be reinforced to meet the requirements of the subsequent engineering construction. Thereinforcing effect of traditional vacuum preloading technology is poor, it is need to make furtherimprovement and technical innovation to achieve the purpose of reclamation silt foundation fastreinforcement.Based on the abundant literatures and references, this paper makes a systematic research onmechanism of closed vacuum preloading method and pressurized vacuum preloading methodwell to consolidate hydraulic filled mud, though indoor model test, field test and grey systemtheory. The main content of this study is as follows:（1）Based on indoor basic test of hydraulic filling mud, a study is done about variousphysical and mechanical indexes, sedimentary characteristics and consolidation behavior ofhydraulic filling mud in wenzhou longwan areas, which provide design basis and practicalreference for dredger fill foundation reinforcement.（2）The laboratory contrast model experimental investigation was carried out about thestraight-line vacuum preloading method and the closed vacuum preloading method forconsolidation of dredger fill foundation, and dwelled on its working mechanism and constructionprocesses of the closed vacuum preloading technology. A systematic research is done about thevacuum transfer and distribution law of the reclaimed beaches silt soil foundation under theclosed vacuum preloading, the settlement deformation of foundation, the change rule over timeand depth of the pore water pressure, the water contents, the vane test strength and so on, so thatit can provide a theoretical basis for the application and development of the closed vacuumpreloading.（3）Based on the model test, combined with the large areas tideland reclamation foundationtreatment project at tiancheng reclamation areas in wenzhou longwan economic andtechnological zone, we done the field tests on the newly hydraulic filling mud foundation usingthe closed vacuum preloading method and the pressurized vacuum preloading method. This paperreports details the working principles, the construction technology and the technical points of thepressurized vacuum preloading method on the reclaimed silt foundation in rapid treatment project.According to the tests and the monitoring data, a comparative analysis is done about the surfaceand the deep layer settlement, the pore water pressure and the soil physical and mechanicalproperties of the reclaimed silt foundation, and then a comprehensive evaluation of consolidationeffect is made for the closed vacuum preloading method and the pressurized vacuum preloading method to treat the newly reclaimed silt foundation. The field tests also validate the validity andreliability of the closed vacuum preloading method and the pressurized vacuum preloadingmethod to reinforce the newly hydraulic filling mud foundation.（4）Application of grey theory model predicts the vacuum preloading settlement andconsolidation degree of soil, can use less of the monitoring data, get a higher precision ofprediction.It has been found that, the effect is good of the closed vacuum preloading method and thepressurized vacuum preloading method to reinforce reclaimed silt foundation, have the highervalue in application.