Distribution of cracks in an anchored cavern under blast load based on cohesive elements

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Explosives Engineering

Background:

• Anchored caverns are critical underground structures.
• Understanding blast load effects on these structures is vital for safety and stability.
• Previous research has not fully detailed crack propagation patterns under dynamic blast conditions.

Purpose of the Study:

• To investigate the distribution and propagation of cracks in anchored caverns subjected to blast loads.
• To analyze the influence of pre-fabricated fractures and their dip angles on crack patterns and cavern stability.
• To examine the dynamic response, including displacement and particle velocity, of surrounding rock masses.

Main Methods:

• Numerical analysis using cohesive elements with zero thickness to simulate crack propagation.
• Modeling of anchored caverns under top explosion scenarios.
• Comparative analysis of crack distribution and rock mass response with varying fracture dip angles.

Main Results:

• Cracks initiate at the arch foot, floor, and vault's anchored zone boundary under blast waves.
• Tensile cracks are prevalent in the surrounding rock.
• The number of cracks at the vault's anchored zone boundary varies with fracture dip angle, with a minimum at 45°.
• Peak displacement and particle velocity are highest at the vault, showing asymmetry with different fracture angles.
• Vault displacement is primarily caused by reflected tensile waves, with fractures decreasing peak but increasing residual displacement.

Conclusions:

• The study provides insights into crack initiation and propagation mechanisms in anchored caverns under blast loads.
• Fracture dip angle significantly influences crack distribution and cavern response.
• Numerical simulations are effective for understanding complex failure mechanisms in underground structures.