  We analyze stress transmission in wet granular media in the pendular state by
means of three-dimensional molecular dynamics simulations. We show that the
tensile action of capillary bonds induces a self-stressed particle network
organized in two percolating "phases" of positive and negative particle
pressures. Various statistical descriptors of the microstructure and bond force
network are used to characterize this partition. Two basic properties emerge:
1) The highest particle pressure is located in the bulk of each phase; 2) The
lowest pressure level occurs at the interface between the two phases, involving
also the largest connectivity of the particles via tensile and compressive
bonds. When a confining pressure is applied, the number of tensile bonds falls
off and the negative phase breaks into aggregates and isolated sites.
