Failure Patterns and Energy Analysis of Shaft Lining Concrete in Simulated Deep Underground Environments

The failure patterns and energy evolution of three types of shaft lining concrete subjected to static and dynamic loading were reported. The energy and damage characteristics of concrete were determined by means of a uniaxial hydraulic servo machine, acoustic emission (AE) equipment, a split Hopkinson pressure bar (SHPB) and an ultrasonic wave analyser. The experimental results indicate that the confluence of multiple cracks forms a penetrating cross section in normal high-strength concrete (NHSC) under the condition of static loading, while the elastic energy that surges out at failure can cause tremendous damage when subjected to dynamic loading. A single crack was split into multiple propagation directions due to the presence of fibres in steel fibre-reinforced concrete (SFRC); adding fibre to concrete should be an effective way to dissipate energy. The non-steam-cured reactive powder concrete (NSC-RPC) designed in this paper can store and dissipate more energy than normal concrete, as NSC-RPC exhibits a strong ability to resist impact. Applying NSC-RPC to the long-service material of a shaft lining structure in deep underground engineering is quite effective.