Experimental On The Effect Of PVDs And Initial Water Content On Vacuum Preloading Reinforcement And Range Of Drainage Dredger Fill

When dredged slurry with high water content,compressibility,viscosity low permeability was treated by vacuum preloading combined PVDs,the soil usually consolidates around the PVDs,while the soil far away PVDs can not be effectively reinforced,resulting in poor overall reinforcement effect of the dredged fill sludge.In order to study the change rule of soil properties during the process of vacuum preloading and the influence of external factors on the final reinforcement effect,indoor model test and field test are carried out in this paper.The main research work and results are as follows:(1)Three groups of laboratory comparative tests were carried out on four PVDs with different lengths,different widths and four dredged silts with different water content.The relationship between theeffect of vacuum preloading and the length,width of PVDs and the initial water content of dredged silt was explored.By monitoring the changes of pore water pressure and vacuum degree along the radial and longitudinal direction in dredger filling sludge,the variation law of each parameter in the reinforcement process is analyzed.Through the analysis of drainage and settlement,the change rule of the outlet water and volume of soil in the consolidation process is obtained.Through testing the water content of soil and the vane shear strength after reinforcement,the change rule of soil water content and shear strength of cross plate under different test conditions is analyzed.(2)According to the experimental data analysis,with the increase of PVD length,not only the overall reinforcement effect of dredger fill mud is better,but also the reinforcement effect of upper soil is promoted;with the increase of PVD,the reinforcement effect of dredger fill mud increases gradually,but when the drainage plate width increases to a certain value,the reinforcement effect will not continue to improve;When the water content of sludge increases,the final reinforcement effect decreases linearly.That is,the higher the initial water content of dredged sludge,the lower the strength of treated sludge.(3)Establish the relationship between the length,width of drainage plate and the initial moisture content of dredged silt and the strength of the soil after reinforcement..(4)Through field tests,the treatment effects of PVDs of different lengths on whole and part of soft soil foundation are compared in non-uniform soil,and the variation rule of soft soil foundation in consolidation process is studied through parameters such as pore water pressure,stratified settlement and lateral displacement,it also validates the results of laboratory experiments in this paper.