Preventing Positive Pore Water Pressures with a Geocomposite Capillary Barrier Drain
SourceThe Geocomposite Capillary Barrier Drain (GCBD) has been developed and tested to prevent positive pore water pressures from developing by laterally draining water while it is still in tension. The GCBD consists of two key layers that function as long as the water pressures in the system remain negative: (l) a transport layer that laterally drains water and (2) a capillary barrier layer that prevents water from moving downward. Prototype GCBD systems have been tested in a 3 m long lateral drainage test apparatus. For most test conditions, the GCBD systems drained water under negative pressures at a rate sufficient to prevent any positive water pressures from developing in the overlying soil. Further, the drain system served as a barrier as it prevented downward flowing water from moving into the underlying soil.