<p>This study introduces a theoretical and numerical model for the spontaneous nucleation and propagation of distributed brittle fractures in initially intact materials. The formulation adopts a kinematic description of nested discontinuities characterized by a micromechanical interface law accounting for cohesion, unilateral contact and friction. The model allows for a unified treatment of the mixed-mode frictional fracture. The implementation of the model into a finite element framework is validated against benchmark tests, exhibiting independence of the discretization. The solution of selected quasi-static boundary value problems demonstrates the predictive capabilities of the framework in capturing key features observed in laboratory tests and in field problems involving confined quasi-brittle materials.</p>