Experimental Study On The Electroosmotic Effect Of Surface-charged Nanomaterials With Different Particle Sizes On Soft Soil

There are a large number of rivers and lakes in china,and the soft soil near these areas is difficult to handle because of its high moisture content,high compressibility,low permeability,and low shear strength.The traditional foundation treatment methods,such as the dynamic compaction method,the surcharge preloading method,the replacement method,and the vacuum preloading method,mainly discharge the free water in the soil,and there is no effective treatment method existing the large amount of bound water of the soil.Electro-osmosis,as a foundation treatment method with a good development prospect,can maximize the diacharge of free water and weakly bound water in soil under a reasonable economic budget,and greatly enhance the bearing capacity of soil.In order to improve the efficiency of electroosmotic drainage,this paper based on the study of the relevant theory of electro-osmosis,using a self-developed electroosmotic experimental device to conduct a series of electrodialysis consolidation drainage test under different conditions.The main work of this article and the corresponding results are as follows.1.The current research status of electro-osmosis and nanomaterials at home and abroad as well as the basic principle of electroosmotic consolidation drainage are foundation treatment methods are compared and analyzed.2.Under the same initial moisture content,a positively charged nanomaterial with different particle sizes was injected at the anode for electroosmotic experiments.The electroosmotic drainage effect of different particle size nanomaterials were analyzed by measuring the discharge and current values in the electroosmotic process and the water content,shear strength and the microstructure of the soil after electro-osmosis.The experimental results show that there is an optimal particle size（550nm）in the electro-osmosis process making the electroosmotic drainage best.At the same time,it was found that the electroosmotic drainage effect of the experimental group was better than that of the blank group.The main reason is that adding a positively charged nanomaterial at the anode can effectively enhance the electrophoretic speed in the electroosmotic process,and some nanomaterials will react with the negatively charged soil particles to generate precipitates,increasing soil compactness and shear strength.3.When the initial moisture content increased,the optimal nano-particle size of soil electro-osmosis also increased slightly.The final displacement of the soil with the nano-particle size curve didn’t change much in the electroosmotic process,and it still conformed to the trend of increasing first and then decreasing.4.The finite element simulation software performed a simple numerical simulation of the electroosmotic test and found that the presence of a certain nanometer particle size makes the electroosmotic drainage effect the best.The size of the nanometer particle size is roughly the same as the experimental results.5.When the initial moisture content was the same,the same amount of positively charged nano-SiO₂@Al₂O₃ solution and negatively charged nano-SiO₂ solution were injected at the anode,respectively.The results showed that the experimental group corresponding to the positively charged nano-SiO₂@Al₂O₃ solution injected at the anode was superior to that of the negative-charged nano-SiO₂ solution injected at the anode in terms of displacement,current density,soil shear strength,and microstructure.