This paper is on my work at Singapore. I think this paper has the following contributions
(1) A concise flow rule is proposed for concrete, every item in the flow rule has clear physical meaning
(2) Let us know that for any material, the flow rule can be simple, and we don't have to pay attention to the potential funcion.
(3) When we propose a plastity constitutive law, we don't have to rely on commercial software like
Abaqus any more, as a numreical calibration method is introduced.
(4) This constitutive law can be extended to other porous material like rock and soil.