Experimental Investigation Of Consolidation Behaviour For Dredged Clays With High Water Contents Under Low Stress Levels

Large amounts of dredged mud could be produced in the dredging of rivers and lakes,construction of ports and waterways,etc.Hydraulic dredging is mainly used in China,produced dredged mud in which method usually have high water contents and low strength.Yard disposal takes a long time and occupies large amounts of land,hence,it's necessary to treat the dredged mud.Drainage consolidation is a treatment method of dredged mud with simple principle and wide application.Due to the low strength of dredged mud,the initial load applied in drainage consolidation treatment is usually small.Existing studies on the consolidation behavior of dredged clays are mostly with the load greater than 12.5 kPa.Therefore,it's of great theoretical significance and engineering application value to study the consolidation behavior of high water content dredged clays under low stress.The main works in this paper are as follows:1)Consolidation tests of five different dredged clays with different initial water contents were carried out,using the low initial stress consolidation apparatus developed by Hong et al.The variations of deformation and bottom excess pore pressure of specimens with consolidation time are analyzed.The mechanism and main influence factors of time-lag phenomena about pore pressure are discussed.2)Based on the data of pore pressure and deformation of the consolidation specimens,the consolidation degree of dredged clays are studied.The effects of liquid limit and initial water content on the consolidation rate are analyzed.The degrees of consolidation obtained by different methods(excess pore pressure dissipation method,Casagrande method and rectangular hyperbola method)are compared.3)Model consolidation tests of high water content dredged clays were carried out with self-developed large-scale consolidation test device.Deformation and pore pressure of soil sample were measured.By comparing the excess pore pressure dissipation time,water contents and undrained strength of soil at different locations,the influence of drainage path on soil consolidation behavior are analyzed.