Energy evolution mechanism of shaft wall concrete under uniaxial loading and unloading compression

In terms of the fundamental problems,such as the premature failure of structural concrete in deep under- ground engineering conditions and the phenomenon of rock burst in high stress areas,the energy dissi-pation and re- lease process of different kinds of concrete were studied by uniaxial loading and unloading compression and acoustic emission tests. The results show that the hysteretic loop of C70 steel fiber reinforced concrete and UHPC tends to be fuller and the capacity of energy dissipation is stronger. C70 ordinary concrete is easy to accumulate energy,when the peak strength is reached,the stored energy is suddenly released,forming the phenomenon of rock burst of concrete. The plastic deformation of steel fiber reinforced concrete is larger in the loading process,which will lead to the formation of flaky fragments when the energy dissipation of concrete. UHPC will dissipate more energy through its own fine cracks, and still maintain a certain degree of integrity after destruction. The ductility of UHPC is better,so it will not cause the destruction of the instantaneous energy. Energy dissipation leads to the deterioration of concrete cohesion and energy release leads to the ultimate destruction of concrete. The adaptive ability of UHPC structure is very strong,which can effectively resist the role of deep high ground stress to protect mine safety.