A new shear creep damage model for rock masses after considering initial damage

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Mine Safety

Background:

• Open-pit mine slope stability is threatened by high slopes with soft interlayers.
• Rock masses possess initial damage from geological processes and mining activities.
• Accurate characterization of time-dependent creep damage under shear load is essential.

Purpose of the Study:

• To develop a constitutive model for time-dependent creep damage in rock masses under shear load.
• To incorporate initial rock mass damage and multi-stage shear creep loading conditions.
• To provide a more convincing description of rock mass creep damage evolution.

Main Methods:

• Defined a damage variable (D) based on shear modulus evolution and initial damage.
• Established a coupled damage equation using Lemaitre's strain equivalence and Kachanov's damage theory.
• Developed and verified a constitutive model against multi-stage shear creep test data.

Main Results:

• The proposed model accounts for initial rock mass damage.
• It successfully describes time-dependent creep damage evolution under multi-stage shear loading.
• Model predictions align well with experimental results from shear creep tests.

Conclusions:

• The new shear creep model offers a more accurate representation of rock mass behavior than traditional models.
• Considering initial damage significantly enhances the prediction of creep damage characteristics.
• This research contributes to improved safety assessments for high-risk open-pit mine slopes.