Experimental Research On Duplex Vacuum Preloading Method To Treat Foundation Of Dredger Fill

Economic developed and population density promote the growing of the scale construction projects in coastal areas of China.However,the shortage of soil has becoming the major barriers in the developing of society.so,we have to extend the land into the sea to meet people’s need.In this context,land reclamation is the major technology to resolved the problem.This technology would to produce much seabed mud and dredger fill that they have these Characteristics of High water content, mobility,and low of carrying capacity.so,they must be deal for construction.Success of vacuum preloading technique’s apply in soft soil foundation became the main technical means to solve this problem.however,Traditional vacuum preloading can not get better result with the shortage of low efficiency of vacuum transfer,requires a lot of sand,the surface will form a crusty layer of deep processing deficiencies and plastic drain clogging. So,it is needed future research and optimization.The purpose of this paper is to invent a duplex vacuum preloading method by research the path of vacuum transfer and some Improvements basis on the Direct pumping sealed vacuum preloading method, This article achieve some conclusions by model test and field test.(1)Saturated dredger fill can not pass vacuumin in the early vacuum preloading.There will be some decline in saturation with the soil consolidation.Then,the soil begin pass vacuum but it still lower than plastic drainage board.(2)The vacuum can be passed directly to the underlying soil.And it can expand the level of pressure between plastic drain and the soil of deep.so it can prompt the pore water into plastic drain and improve the effect of enforce in deep soil.(3)Air-boosted vacuum preloading can extend the level pressure and improve the Treatment effect to zhese soil between Plastic drainage board and Pressurization filter tubes.however, the effect of booster mainly reflected between Plastic drainage board and Pressurization filter tubes.it’s impact is litter to the soil out of Pressurization filter tubes.(4)Stage vacuum preloading method can improve the overall effect of soil reinforcement and decrease clogging of soil and Plastic drainage board.It shows that size smaller soil particles are carried less when the pore water seepage.Practice has proved that duplex vacuum preloading method can improve the effect of soil reinforcement. There is a high engineering value in use.