Intersecting fracture impacts

Figure 10 presents the evolution of the maximum principal compressive stress in the buffer and back-fill. Figure 10 shows that stress begins to develop near the intersecting fracture and then in the lower parts of the buffer. This result shows that an intersecting fracture impacts the stress evolution and its spatial distribution in the buffer. 

The fractures on a plane surface, created by the collisions of hard spherical particles at low-impact velocities, may form a conical crack according to the Hertzian quasi-static stress theory. In a multiple-impact situation, the conical cracks meet those extending from neighboring impact sites, and then the brittle material becomes detached. Once appreciable damage is done, the cracking mechanism may be altered because the particles no longer strike on a plane surface nevertheless the brittle removal continues by the successive formation and intersection of cracks. 

The thickness of the low permeability fault rocks is an important variable in evaluation of cross-fault flow behaviour. Because fault zones are usually composed of complex arrays of intersecting sub-seismic faults and fractures and because the permeability reductions associated with faulting develop after low amounts ( cm) of displacement incorporation of the impact of complex fault zones (as opposed to single faults ) is not a simple procedure. 

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