In order to explain the failure and breakage mechanisms of structural geological materials

the plane strain compression tests of the samples of prismatic structural bodies assembled in two different patterns are conducted under different confining stresses. During the breaking process of structural bodies

it is found experimentally that the main failure modes of structural bodies are splitting

shear failure and crushing

but finally the breakage bands form; while the confining stress increases

strain softening gradually turns to be strain hardening; when the lateral stress is low

strain softening and volume expansion and lateral extrusion can be observed; however

when the lateral stress is high

strain hardening

volume contraction and lateral contraction become prevalent; whatever the confining stress is and which pattern the structural bodies are assembled by

the rotation of the structural bodies is hardly observed.