Expansive soil samples reinforced with a biaxial geogrid are adopted to carry out a series of unconfined compression

consolidated and undrain tests at different water content. Effects of water content on the strength and deformation characteristics of reinforced expansive soils are studied. Water content has significant effect on the failure model of reinforced expansive soils; With increasing water content

the effect of reinforce on the stressstrain curves decreases

and the change of peak strength and residual strength decrease. Water content has little effect on the failure mode

in which all the stress-strain curves show strain-hardening; With increasing water content

both the peak strength

and increment after reinforcement decrease sharply. The effect of water content on the initial yield stress is related to the layers of reinforce.