Damp Areas Electroosmosis Treated Wet Packing Technology Research

Mostly when digging up roadbed and filling material in the rainy humid areas, because the soil is over-humid, the soil can not be dispersed or compacted effectively, so we must take some relevant actions. This paper adopts the method of electro-osmosis to research into the over-wet filler with dry disposal. In the laboratory for the following three types of soil: cohesive soil, poorly graded gravel with silt, poorly graded gravel with little silt, we respectively use three methods: free drainage, vacuum drainage and electro-osmosis drainage, then analyze and contrast the experiment data. The experiment results indicate that for the same soil sample, the efficiency from high to little is electro-osmosis drainage, vacuum drainage, free drainage. The electro-osmosis drainage is the most effective for various kinds of soil sample. The more the fineness of soil sample is small, the more electro-osmosis drainage is effective; but when use free drainage or vacuum drainage to deal with the soil sample which have small size composition, the effect is not ideal. The results of the experiment also indicated that the speed of electro-osmosis drainage is relevant to the form of arrangement of the voltage, the current and the electrode, and increasing the voltage or reducing the distance between electrode is the effective method to accelerate the process of drainage; there are three parts in the process of electro-osmosis drainage: driven by electric field, free drainage and evaporated by electrifying, the ability of electro-osmosis drainage is reduced with time. By measuring the voltage in the region of electro-osmosis, a standpoint can be confirmed that the distribution of electic field is nonlinear in soil sample and the gradient of voltage near the cathode and anode is large and small far away from the electrode, which explains that the hypothesis of Esrig's classical electro-osmosis consolidation theory about the linear distribution of voltage has obvious deviation with the truth, at the same time, while it supports the point that there is interface electric resistance between electrode and soil, and it is necessary to consider the interface electic resistance in the calculation in the region of electro-osmosis.In the electro-osmosis experiment at ShuiMa Freeway in Yunnan, we took the D.C. electric welding machine as power source, under average voltage 60．75 v, and then the average moisture of gravelly soil is successfully reduced form 19．1% to 12．3 % after 331 hours, and this exceeds only 2．6 present than its optimum state (heavy compaction test). The experiment proved that the electro-osmosis can be leaded into dealing with the over-wet soil, and enlarging the scope of using electro-osmosis in geotechnical engineering. There are some problems that the soil near the cathode still has high moisture content after dealing with electro-osmosis by moisture content testing. The electro-osmosis experiment in the field had acquired a series of important achievement and data, including the design of electro-osmotic parameters, consruction technology and control, monitoring, and analysis of the experiment and achievement. On the basis of summarizing the experiment achievement and the formerly practice of electro-osmosis, according to the general theory of electro-osmosis and principles of electricity, we put forward the process of designing how to deal with the over-wet soil, and by comparing calculations with actual observation, this computational method is proved applicably, and this method can not only improve the expectancy of electro-osmosis but also have some guiding action for putting electro-osmosis into effect and it is also benefit for evaluation of benefit. The calculation is helpful to estimate the electric current more accurately in the process of electro-osmosis by leading the interface electric resistance into the calculation in the region of electro-osmosis and considering the influence of adjoining electrode.At last, it discusses adopting excessive humid filler to roadbed construction directly in the raininess humidification area and lowland plain area, should not regard dry density corresponding to optimum moisture content as construction standard in the last of article. Constructing dry density, however, should be controlled by achievable maximum strength under the terms with actual moisture at the time of compacting backfill. This article put forward corresponding countermeasure and concept, measurements of roadbed moisturize in view of the above.