The high normal stress and constant normal stiffness are the general boundary constraint features of deep rock joints. Advanced rock joint shear servo test system with high normal load

large shear area

multi-shear mode and long shear distance is the premise for understanding the shearing deformation and failure of rock joints in deep stress condition. Thus

a new shear servo testing system

with large-scale

multi-functional and high-pressure

is invented. The system consists of normal and shear loading and unloading subsystems

servo control subsystems

data acquisition and software subsystems

and hydraulic oil source auxiliary subsystems. The functional parameters of the testing system include the maximum normal load of 1 500 kN

the maximum shear load of 2 000 kN. This testing system is available for the rock joint shearing test on the sample with standard sizes of 20 cm×10 cm×20 cm

30 cm×20 cm×30 cm and 50 cm×30 cm×30 cm (length×width×height). The testing system can finish complex loading and unloading

constant normal loading (CNL)

constant normal stiffness (CNS)

fast/slow shearing

reciprocating shearing and other loading modes

assisting with shear observation window and acoustic emission positioning monitoring. Based on the test specimens of cement material and rock specimens

the experimental results show that this servo testing system can achieve high-frequency feedback control and data acquisition due to the excellent hardware structure and efficient software control

which can give out stable and reliable experimental data

support the stability study and engineering application analysis for deep rock engineering.