Experimental Study On Consolidation Of Dredged Silt By Cyclic Varying Temperature Load Combined With Vacuum Preloading

According to statistics,in 2021,the output of dredged silt in my country will reach 74.624 million tons.For the development and utilization of this type of soil,the method of vacuum preloading reinforcement is usually adopted.Regarding the clogging phenomenon in the drainage plate,whether it is the traditional vacuum preloading test,or the combined chemical additives,rapid mud-water separation and other technologies,it will cause a long consolidation time,high energy consumption,environmental pollution,and difficulty in meeting the needs of the project.Problems such as knot degree.Considering that temperature changes can accelerate molecular movement,reduce the viscosity coefficient of water,and increase the permeability coefficient of soil,it is a good choice to use temperature load combined with vacuum preloading for reinforcement.This paper takes the dredged sludge of Wenzhou Oufei Project as the test object.Through temperature-controlled consolidation permeameter and indoor model box test,the effect of temperature on the mechanical properties of dredged sludge is comprehensively studied.The specific contents include:(1)The effect of temperature on the consolidation characteristics of dredged silt was studied.The results show that the consolidation rate of dredged sludge can be accelerated with the increase of temperature regardless of the rapid consolidation test and standard consolidation test.The correction coefficient K of fast consolidation method is put forward,and the applicability of fast consolidation method in foundation treatment engineering is discussed.(2)Based on the consolidation and permeability test of dredged silt under constant temperature and cyclic variable temperature load,the law of soil compression and deformation under different temperature paths is studied,and the influence of temperature on soil permeability coefficient is analyzed;the logistic function equation is used to fit,To discuss the mechanism of temperature effect on the consolidation of dredged silt;through micro-electron microscope scanning,the influence of temperature load on the microstructure of soil is analyzed,which enriches the content of the theory of thermal consolidation of dredged silt.(3)A series of model tests were carried out for the method of temperature combined with vacuum preloading to consolidate dredged sludge,and the relationship between temperature gradient and transfer rate was summarized,and the influence of temperature on the consolidation efficiency of dredged sludge was analyzed.Provides a basis for experimentation.(4)Based on the theory of cyclic variable temperature consolidation,the best grade temperature cycle path suitable for practical engineering applications is obtained.The test data shows that under the premise of ensuring the degree of consolidation,parameters such as energy consumption coefficient and carbon emissions have reached the best values in this test,effectively improving the clogging problem of the drainage board,and providing foundation treatment projects in Wenzhou area.Theoretical guidance.