A live soft gabion is a biotechnical slope stabilization technique that incorporates significant quantities of nonliving material into its construction. The soft gabion (or geogrid) portion of the structure is a geotextile- either natural (such as jute) or synthetic, which serves to hold soil and or rocky backfill in place until roots from live cuttings grow enough to serve that purpose.
In addition to the significant amount of nonliving material used, there is another difference between this and the techniques discussed previously. Construction of live soft gabions involves major earthmoving, which more or less requires the use of heavy machinery. As such it is a capital intensive process and best suited to projects where valuable infrastructure is being protected, such as roads, bridges, and buildings.
IThis technique allows for stabilization of steep slopes where live fascines and brushlayers alone are simply inadequate. Rather than stabilize the existing slope surface with such techniques, the area being worked on is excavated and rebuilt, a major intervention that allows for recontouring and creation of stability deep within the slope.
Live soft gabions involve significant excavation, in order to rebuild a slope, rather than simply trying to hold it in place. This allows stabilization of longer steeper slopes than those techniques discussed previously. It is also much more ambitious, and largely outside the scale of what I intend to be doing.
The end result is comparable in strength to many of the "hard" engineering structures that most engineers are familiar with, but as a softer option, does so with reduced impacts. Use of heavy machinery keeps the costs competitive (given the less expensive inputs) as well. However, due to the comparatively capital intensive nature of this technique it lies largely outside of the scope of projects which I am interested in working on. On a small scale however, a project which called for a few short courses of live soft gabions built by hand or with the help of a bobcat is concievable. Mostly I mention it here just to illustrate what is possible.
Continued: Live Cribwalls
Live soft Gabions, From: Stream Corridor Restoration: Principles, Processes, and Practices, 10/98, by the Federal Interagency Stream Restoration Working Group (FISRWG).
Construction of Live Soft Gabions at base of road cut on Highway 68 west of Calgary, Alberta
Same road cut, second course
Use of heavy machinery aids in backfilling Live Soft Gabions at base of road cut