Microscopic Mechanism And Experimental Study Of Electroosmotic Drainage

Muddy soil has the characteristics of fine particles,high water content and low permeability.It is difficult to drain quickly by traditional reinforcement methods to meet the needs of engineering construction.The electroosmotic drainage method has a good application prospect due to its short reinforcement time and low noise.However,due to the limited understanding of the microscopic mechanism of the electroosmotic drainage method and the decrease of the electroosmotic effect caused by the cracking of the soil in the later stage of electro-osmosis,it hinders wide application of electroosmotic drainageIn this paper,a series of electroosmotic drainage model tests were carried out on a silt soil in a river in Nanjing,including the comparative study of physical and mechanical properties of silt soil before and after electro-osmosis,and microscopic mechanism analysis of electroosmotic drainage,and experimental studies on injecting the electrolyte solution and adjusting the electroosmotic conditions to improve the effect of electro-osmosis.The main conclusions are as follows:1.The liquid,plastic limit and plasticity index of the soil decreased after electro-osmosis;the cohesive force and internal friction angle of the soil decreased after electro-osmosis,that is,the soil attenuated under certain conditions after electro-osmosis.2.In this paper,the microscopic mechanism of electroosmotic drainage is improved by semi-permeable membrane theory.The microscopic mechanism of electroosmotic drainage proposed in this paper is verified by water quality analysis test and scanning electron microscopy.It is also suggested that the loss of cations in the soil is the microscopic mechanism leading to the attenuation of strength.In addition,the microscopic mechanism of electroosmotic drainage proposed in this paper is used to further explain the phenomenon of soil cracking during electro-osmosis.3.Using the method of injecting electrolyte solution to improve the effect of electroosmotic drainage,the results show that the injection of calcium chloride solution during electro-osmosis helps to improve the electroosmotic effect,and the optimal injection concentration of calcium chloride is 10%.The best injection position is the anode4.After quantitative analysis of fractures,it is shown that the inhibition of the extension and expansion of soil cracks during electroosmotic drainage is beneficial to the effect of electroosmotic drainage.5.The method of combined support of pile-loading + electro-osmosis is more conducive to the discharge of water in the soil than the simple electro-osmosis.There is the best load value of the pile in the test.The optimal pile-load value can be used to make the cumulative displacement of the electro-osmotic drainage.At the same time,the time cost and economic cost of electro-osmosis can be saved.