Experimental Investigations on Rheological Properties of Mudstone in Kilometer-Deep Mine

Table 7

Failure modes of mudstone rheological test specimen.

Stress environment	Type of rheological test	Failure form of test piece	Maximum deviating stress (σ1−σ3) (MPa)
Period affected by driving	A—unloading confining pressure with axial compression rheological test	Shear failure	63
Period affected by stable driving	B—unloading confining pressure with constant axial pressure rheological test	Shear failure	57
Period affected by mining	C—uniaxial rheological test	Splitting failure	40