The Problem Is Liquefaction

A building toppled due to liquefaction after the 1999 Turkey earthquake.

Stone Columns Are Expensive And Unpredictable 

The use of stone columns provides a more comprehensive defense against liquefaction.  Not only is densification achieved, but the stone provides some drainage to make the build-up of the pore water pressure more difficult, and adding to the energy required by the earthquake to induce liquefaction.  Besides the expense of the stone, the main drawback of this system is that the permeability of the stone column is difficult to determine after it has been contaminated by the soil fines.

What Are Earthquake Drains?

Earthquake drains consist of a high flow capacity prefabricated vertical drain wrapped with a geotextile fabric. Typically the diameter is about 75 mm (3 inches). The core is tightly wrapped with proven durable geotextile filter fabric, selected for its excellent filtration properties, allowing free access of pore water into the drain, while preventing the piping of fines from adjacent soils. The geotextile wrap is also very durable, and able to withstand the handling and abrasion that occurs during installation. Several core designs and fabric types can be utilized to suit a variety of drainage applications and soil classifications.

How Are They Installed?

Earthquake drain installation.

Earthquake Drains Work!

It has long been recognized that geosynthetic products such as wick drains, edge drains, geotextiles, geogrids, etc. outperform traditional construction materials at a lower cost. Vertical prefabricated (wick) drains have completely replaced expensive and inefficient sand drains for acceleration of consolidation.

Nilex has used it's expertise in geosynthetics and soil penetration to develop a patented system to install a synthetic drain while simultaneously densifying the surrounding soil.  This two-pronged defense of installing synthetic drains to prevent liquefaction has steadily gained acceptance worldwide as the most cost-effective method to prevent the devastating damage caused by earthquakes.