The invention discloses a testing device for rock three-axis
external pressure and hole internal
hydraulic pressure coupling loading and unloading. The testing device is composed of a base, a confining pressure loading and unloading
system, a hole internal
hydraulic pressure loading and unloading
system and an
axial pressure loading and unloading
system. The confining pressure loading and unloading system comprises a pressure chamber, a confining pressure bag, a protection tire, an oil inlet and outlet channel and a confining pressure electro-hydraulic
servo system. The hole
internal pressure loading and unloading system comprises an inner pressure bag, an upper sealing member, a lower sealing member, an upper L-shaped
elbow, a lower L-shaped
elbow, an upper cover plate, a lower cover plate and an
internal pressure electro-hydraulic
servo system. The
axial pressure loading and unloading system comprises a loading block, a
piston rod, an oil cylinder, an upper oil cavity channel, a lower oil cavity channel and an
axial pressure electro-hydraulic
servo system. The testing device is compact in structure, and all functions are independent and collaborative; different non-uniform
radial stress fields and different non-uniform
tangential stress fields, all of which are distributed in the circumferential direction can be constructed by adjusting the different confining pressure and
internal pressure combinations, and linear and nonlinear radial unloading and tangential loading stress paths at points on the non-uniform stress fields in a
rock sample can be achieved by adjusting the unloading rate of the internal pressure in a servo mode.