EKG Remediation of Embankment

Forest of Dean slope stabilisation

Low Impact Benefits

Highway Embankment Stabilisation

Sewage Sludge

Mine Tailings

Railway Embankment Stabilisation

Reinforced Soil

Lagoon Consolidation

Consolidation of Soft Soil

Consolidation of super Soft Soil

EKG has been used in the form of an electrically conductive prefabricated vertical drain (e-PVD), to consolidate super soft kaolin clay. A large test pit was filled with kaolin clay with a moisture content of 85% to a depth of 2.4m with EKG vertical drains installed as shown in. The clay was left to settle for 100 hours, resulting in a consolidation of 20mm.

Electroosmosis was then applied for a period of 500 hours which produced further consolidation of 340mm and an increase in shear strength from < 1kN/m² to 15–30kN/m². To produce an equivalent result using conventional means would have required a surcharge loading of 10m of fill, which would have been impossible to place on the super soft soil.

During electro-osmosis water flows from the anode to the cathode; as a result the area around the anodes experiences the greatest reductions in moisture content and improvement in shear strength. In order to minimise moisture content anisotropy, the trial was completed with a phase of polarity reversal in order to draw water away from the electrodes which were acting as anodes in the first phase. Polarity reversal resulted in a more even distribution of shear strength in the soil.

Large lab scale consolidation of super soft soil using EKG

	Day 1 - 85% water content and undrained shear strength = 1.5 kPa
		24 days normal polarity
		16 days reverse polarity
	Day 40 - 62% water content / undrained shear strength = 35 kPa

The trial demonstrated that dewatering/consolidation using EKG prefabricated drains is rapid, effective and, energy efficient. For full scale applications, consolidation by EKG has a number of potential advantages over conventional wick drain technologies:

• it is faster

• no surcharge is required

• the effectiveness of the e-PVD is unaffected by kinking or smearing as consolidation proceeds