Abstract: Based on the background of steel fiber concrete lining support for deep shafts in Yunnan Province. Cement, steel fibers,and waste gangues from the deep mine were utilized as raw materials to prepare steel fiber concrete samples. The dynamic and static mechanical properties of concrete with different steel fiber types have been investigated. The dynamic and static mechanical properties of steel fibre concrete and failure modes were obtained by uniaxial compression tests,Brazilian splitting tensile tests and dynamic compression tests. Furthermore,the crack evolution in steel fiber concrete was studied by using high-speed cameras and digital image correlation (DIC) method. The results show that the compressive strength of concrete mixed with three or double types of steel fibers is higher than that of concrete mixed with single types of steel fibers. The concrete mixed with three types of steel fibers is the most effective on increasing the tensile strength of the concrete. The dynamic compressive strength increases with the addition of steel fiber types. Surface cracks appeared later in steel fibre concrete specimens compared to plain concrete. The more types of steel fiber mixed,the higher the peak strain of the steel fiber concrete specimens. Plain concrete exhibits brittle failure characteristics,and steel fiber concrete shows ductile failure behavior. The concrete mixed with three types of steel fibers is used in mine shaft lining support,which effectively improves the integrity and stability of the shaft wall and provides a guarantee for the safety and high efficiency of the deep mining engineering.

Key words: steel fiber concrete,mechanical strength,strain evolution,digital image correlation