Experiment of bursting liability of deep underground concrete under complex stress conditions

Under complex stress conditions,instantaneous destruction like rock burst occurs on deep underground con- crete. For this problem,the compressive strength,splitting tensile strength,duration of dynamic fracture,elastic strain energy index,bursting energy index and acoustic emission parameters of concrete with different strength levels were studied. It shows that the concrete,whose brittleness index is less than 20,the duration of dynamic fracture is greater than 500 ms and bursting energy index is more than 1. 5,has no bursting liability. The low-strength concrete below C50 has no bursting liability while high-strength concrete has bursting liability. As concrete strength level increases, bursting liability rises. Acoustic emission tests were carried out,which displayed that high-strength concrete had more acoustic emission energy. When concrete specimens approach the peak stress,the acoustic emission parameters have an explosion,which can be used to monitor the impact failure of high-strength concrete. Reactive powder concrete can ef- fectively improve the duration of dynamic fracture,depress brittleness index and bursting energy index,and it has no bursting liability. Therefore,it can obviously reduce the impact failure of concrete under complex stress conditions.