The influences of confining pressure

end constraint

height of specimen and interface on networks of shear bands are investigated numerically. Firstly

some factors including height of specimen

confining pressure

temperature

axial strain and different numerical methods were discussed. Secondly

the FLAC 3D was used to simulate planar multiple shear bands and friction angle and cohesion force were dependent on plastic strain. The conditions

under which the multiple shear bands tend to form

were discussed. As end constraint is strong and confining pressure exists

the multiple shear bands appear in the center of specimen. For weak end constraint

the multiple shear bands form in the end of the rock specimen and numbers of shear bands increases with height of specimen. For large normal and tangential rigidity

shear bands can penetrate old fault and propagate along their inherent directions and the form of networks of shear bands is very apparent. The results obtained agree with many experimental tests and can be used to explain some phenomena of shear strain localization in seism.