Comparison of analytical result and measures result.

<p>The trends of the mean measured value and the mean analytical value processes were comparable. The mean analytical result agreed well with the mean measured value during the first 5 h. Different value appeared 5 h later, when the mean measured result was larger than the mean analytical result. Electrolytic exothermic and chemical reactions among ions can give rise to changes in the pore-water pressure, which was neglected by the analytical derivation The final mean measured value was about 61 kPa.</p

Analytical model.

<p>Figure 1 illustrated the unit cell adopted for plane strain conditions. The change of flow occurred in the <i>z</i> direction and <i>x</i> direction. (A) <i>dQ</i>_x demonstrated the flow in the <i>x</i> direction of the drain from the entrance to the exit of the unit cell. (B) The total change in flow from the entrance face to the exit face of the unit cell was given by <i>Q</i>_z. (C) Considering the incompressibility of water, <i>dQ</i>_x was equal to–<i>dQ</i>_z. The equation can be established according to plane strain unit cell.</p

Real photo of experiment apparatus.

<p>The panorama of test apparatus was showed. (A) Model device expressed the process of test. The EKG electrodes were linked to the electric source through electric wires. (B) The pore pressure gauges were linked to the readout instrument through electric wires to record the data. (C) Vacuum pump and pump controller were used to control the vacuum degree.</p

Diagram for the EKG electrode.

<p>Both sides of the EKG were covered with drainage tray, copper wires and a conductive geomembrane. It contained polyethylene, carbon black, and graphite (mass ratio = 1: (0.3~0.35): (0.05~0.1)). The copper wires were protected by the electric polymer plastics and transmission electric energy during the test. So, the mental corrosion can be avoided to guarantee the effect of experiment.</p

Diagram of model device.

<p>The model device was made of organic glass (L×W×D = 250 mm×200 mm×500 mm). It contained EKG electrodes, pore pressure gauge, vacuum membrane and sand cushion. The sand cushion was placed at the top of the soil sample. A vacuum membrane was used to isolate the sample from the air.</p

Basic parameters for the laboratory experiment.

<p>Basic parameters for the laboratory experiment.</p

Real product of the EKG electrode.

<p>The functions of EKG materials included drainage, electric conduction and corrosion resistance. This new material can relatively shorten the consolidation time when compared with the conventional test and can also avoid the electrolytic reaction of metal electrodes during the test. Thus, the EKG can make the coupling between the electric seepage field and the hydraulic seepage field more effectively.</p

An analytical solution for two-dimensional vacuum preloading combined with electro-osmosis consolidation using <i>EKG</i> electrodes

<div><p>China is a country with vast territory, but economic development and population growth have reduced the usable land resources in recent years. Therefore, reclamation by pumping and filling is carried out in eastern coastal regions of China in order to meet the needs of urbanization. However, large areas of reclaimed land need rapid drainage consolidation treatment. Based on past researches on how to improve the treatment efficiency of soft clay using vacuum preloading combined with electro-osmosis, a two-dimensional drainage plane model was proposed according to the Terzaghi and Esrig consolidation theory. However, the analytical solution using two-dimensional plane model was never involved. Current analytical solutions can’t have a thorough theoretical analysis of practical engineering and give relevant guidance. Considering the smearing effect and the rectangle arrangement pattern, an analytical solution is derived to describe the behavior of pore-water and the consolidation process by using EKG (electro-kinetic geo synthetics) materials. The functions of EKG materials include drainage, electric conduction and corrosion resistance. Comparison with test results is carried out to verify the analytical solution. It is found that the measured value is larger than the applied vacuum degree because of the stacking effect of the vacuum preloading and electro-osmosis. The trends of the mean measured value and the mean analytical value processes are comparable. Therefore, the consolidation model can accurately assess the change in pore-water pressure and the consolidation process during vacuum preloading combined with electro-osmosis.</p></div