ABSTRACT
Expansive soft rock are those low strength engineering rock that containing high dilatability minerals (clay, etc.), and in the lower stress level (<25 MPa) shall have significant plastic deformation. In engineering practice, expansive soft rock geological features are low-intensity engineering rock generally consist mainly of argillaceous rocks, which significant characteristic is containing large amounts of clay minerals and has dilatability, and divided according to their expansive size: strong expansion soft rock (free expansion deformation > 15%), the expansive soft rock (free expansion deformation of 10% to 15%) and weak expansive soft rock (free expansion distortion <10%).
