Influence of In-Situ Stress on Cut Blasting of One-Step Raise Excavation Using Numerical Analysis Based on a Modified...

Area of Science:

• Rock mechanics
• Blasting engineering
• Computational modeling

Background:

• Rock material exhibits distinct tensile and compressive properties, leading to different damage evolution patterns.
• Understanding these differences is crucial for optimizing deep cut blasting in varied in-situ stress conditions.

Purpose of the Study:

• To investigate the influence of in-situ stress on tensile and compressive damage evolution during deep cut blasting.
• To develop and implement an improved material model for simulating these phenomena.

Main Methods:

• An enhanced Holmquist-Johnson-Cook (HJC) material model, separating tensile and compressive damage, was developed.
• The improved HJC model was implemented in LS-DYNA using a user-defined subroutine.
• Numerical simulations were conducted with varying in-situ stress loading schemes.

Main Results:

• In-situ stress was found to inhibit tensile damage while promoting compressive damage.
• Increased in-situ stress led to a reduced overall damage zone due to tensile damage sensitivity.
• Maximum principal stress dictates the direction of damage propagation.

Conclusions:

• The developed HJC model accurately simulates damage evolution under different in-situ stresses.
• Optimized blasting designs, considering in-situ stress, are essential for successful deep excavations.
• Field application demonstrated the model's utility in addressing practical challenges in blind cut raise excavation.