Strength and stress-dilatancy behaviour of bioemented sand under plane strain condition

The strength and stress–strain properties of biocemented soil have been studied mainly under axisymmetric conditions. However, most of the geotechnical problems are under plane-strain, if not three dimensional loading conditions. Therefore, a series of drained plane strain tests were conducted to characterise the failure and stress–strain behaviour of biocemented sand under plane strain conditions. The behaviour of biocemented sand is much more affected by the consolidation history as the bonding begins to break during the K₀ consolidation stage when the consolidated stress is larger than the yielding stress. The increasing calcium carbonate content makes the biocemented sand more brittle and dilative. The work done on the biocemented sand is assumed to be dissipated by the friction between sand particles and breakage of bonding structure. Both the friction angle and the effective cohesion of biocemented sand increase with the increasing in the calcium carbonate content by following an exponential relationship. The friction angle is higher and the effective cohesion is lower under plane strain condition than those under axisymmetric condition.