Cohesive granular materials are known for their pressure-dependent strain softening behavior that is intimately linked to their microstructure and grain interactions. To understand the relationship of mechanical properties, composition and structure of these materials, we have been developing continuum theories utilizing higher displacement gradients and micromechanics [1-5]. In this presentation, we will first describe the second gradient continuum theory using the principal of virtual work to establish the governing equations and the boundary conditions. We will then describe the derivation of constitutive equations for this theory using a granular micromechanics approach. The model predictions will be shown to have both quantitative and qualitative consistency with the observed behavior of cohesive granular material obtained in experiments and through ab initio atomistic simulations. We expect that the proposed approach can be used to correlate measured mechanical properties at micro/nano-meter scales with truly atomic-scale information for systems that possess complex structures at atomic and micro-scales.