The nonlinear propagation of dust-acoustic (DA) waves in an unmagnetized dusty plasma (containing positive and negatively charged inertial dust grains and nonextensive distributed electrons and ions) have been investigated theoretically. Three different types of nonlinear dynamical equations, namely, Korteweg-de Vries (K-dV), modified K-dV (mK-dV) and Gardner equations have been derived by employing the reductive perturbation method. The basic features (viz., polarity, amplitude, width, etc.) of solitary waves have been also analyzed numerically. It has been observed that the effects of nonextensivity of electrons and ions, mass and charge of positive and negative dust, and different dusty plasma parameters have significantly modified the fundamental properties of the solitary waves.