Laboratory Test And Numerical Simulation Study On Electro-Osmosis Reinforcement Of Wet Subgrade During Operation Period

The moisture content of the subgrade greatly affects the bearing capacity of the subgrade.Filling roadbed with over-wet soil will delay construction process and various hidden dangers will appear.In addition,the phenomenon of water migration and humidity redistribution will lead to an increase of the moisture content of the subgrade soil,which caused water damage to the highway during the operation period.Therefore,reducing the moisture content of over-wetted roadbed during the operation period plays an important role in ensuring the use of the subgrade.Electro-osmosis method is often used for drainage of soil with high water content.It has the advantages of high drainage efficiency,fast consolidation of soil and is not affected by soil particles and is often used in foundation drainage.In this paper,electro-osmotic drainage process of over-wetted roadbed during operation was studied by using the self-designed three-dimensional laboratory test model box.The consolidation drainage results of the soil model under different electro-osmosis parameters were studied.The numerical simulation method validates the model test and provides a reference for the use of electro-osmosis in engineering.The main research results and conclusions of the paper are as follows(1)This paper designed a set of subgrade electro-osmosis drainage test model system.Using this system,the drainage process of over-wetted roadbed during operation subgrade was simulated.The subgrade drainage process under different drainage conditions such as different types of electrifying,voltages and initial soil moisture contents were studied.The test parameters such as the displacement,water content,settlement and energy consumption of the soil during the test were analyzed(2)The results of the subgrade under different types of electrifying are quite different.Compared with continuous electrifying,intermittent electrifying and intermittent electrifying with reversal electrode can effectively extend the treatment time and have better drainage effect.The drainage effect of intermittent electrifying and intermittent electrifying with reversal electrode are similar.But the intermittent electrifying with reversal electrode effectively reduces energy consumption during drainage process.(3)The efficiency of electro-osmosis drainage increases with increase of voltage,and energy loss is affected by voltage.When the voltage is too low,the effective electrical energy of soil drainage is not enough,resulting in low electroosmotic efficiency.As the electrifying voltage increases,the electro-osmosis efficiency increases.The moisture content of the treated subgrade filler will meet the engineering requirements when the electrifying voltage reaches 45V.Excessive energizing voltage will increase the loss of electrical energy,and the final moisture content of the soil will not decrease obviously.The optimal energizing voltage in this experiment is 45V;(4)As the initial moisture content is too low,electro-osmotic drainage cannot be performed.Different soil initial moisture content only affects the drainage efficiency in the early stage of drainage and has little effect on the drainage efficiency in the later stage;(5)Numerical simulation can effectively analyze the electro-osmosis results.By comparing the results obtained from the numerical simulation with the test results,it can be found that the electro-osmosis method can effectively reduce the moisture content of the subgrade.The influence of the water content to the soil resistance is not considered in the numerical simulation,causing the calculation results differ from the experiment results.