1st generation – Natural textiles and fabrics used on an ad-hoc basis during construction
2nd generation – Synthetic textiles and fabrics used on an ad-hoc basis during construction
3rd generation – Synthetic textiles designed for specific ground engineering functions including drainage, separation, reinforcement, containment and filtration
4th generation – Composite geosynthetics designed to combine 3rd generation passive functions with active and controllable electrokinetic functions
Casagrande (1952) used electroosmosis to increase soil shear strength and thus stabilise steep railway cuttings in 1939. However, since then the widespread application of electrokinetics has been prevented because of a variety of problems, frequently related to the limitations of available electrodes. These included:
- Corrosion of the anodes
- Difficulties in removing fluids (water and gasses) at the electrodes
- Poor electrical contact of electrodes with the soil
- The cost of producing functioning electrodes
- Impracticality of polarity reversal
- Limitations related to the physical form of the electrodes
Many of these historical limitations have been eliminated by the introduction of EKG which uses geosynthetics as electrodes and thus combines the technologies of geosynthetics and electrokinetics
The concept of the combination of electrokinetic phenomena with geosynthetic
materials has greatly reduced the problem of electrode corrosion and, owing
to the design of the EKG electrodes, current density and electrical contact
with the soil are dramatically improved.
By forming the electrode as a geosynthetic, EKG overcomes the problem of removing
electroosmotically gathered water by utilising the drainage function of geosynthetics
and it provides the additional advantages of exploiting geosynthetics' reinforcing
and filtration characteristics and their ability to take on a wide variety
of shapes and forms.
Furthermore, because the electrodes can be made identical, they can function
equally efficiently as either cathode or anode, making polarity reversal (a
crucial procedure in ground consolidation) easy to implement with EKG.
