Bio Polymer slurry trenching differ from normal slurry trenching in two ways. First, the slurry used to support the trench walls during excavation is made from a biodegradable material such as guar gum or polymer. Second, the trench backfill is a pervious material.
An important consideration when designing a trench excavated under bio-polymer slurry is to analyze the stability of the excavated trench. The characteristics of bio-polymer slurry are different from those of bentonite slurry. In particular, bio-polymer slurry does not maintain the soil particles in suspension after completion of the excavation, thereby significantly decreasing the hydrostatic pressure of the slurry against the trench wall after completion of the excavation. This could result in unstable trenches, mostly for deep trenches when the ground water is close to the work platform.