基于深地复杂应力条件下混凝土冲击倾向性试验

针对深地复杂应力条件下，混凝土发生了类似岩爆的瞬时破坏现象。对不同强度等级的混凝土的抗压强度、劈裂抗拉强度、动态破坏时间、弹性能量指数、冲击能量指数和声发射参数进行试验研究，提出以脆性系数、 动态破坏时间、冲击能量指数作为评价混凝土冲击倾向性指标。结果表明:脆性系数小于20、动态破坏时间大于500 ms、冲击能量指数小于1.5的混凝土无冲击倾向性，C50强度等级以下的混凝土无冲击倾向性，强度越高冲击倾向性越强;对高强混凝土进行声发射监测，声发射能量随混凝土强度增加而增大，临近峰值应力时，声发射参数会剧增，可据此监测高强混凝土的冲击破坏;活性粉末混凝土显著提高了动态破坏时间，降低了脆性系数和冲击能量指数，是一种无冲击倾向性的材料，对深地复杂应力条件下混凝土的冲击破坏有明显改善。

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 concrete.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 effectively 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.