混凝土Ⅱ型断裂破坏试验及其断裂韧度的确定

Experiment Research of Concrete ModeⅡ Fracture and Determination of Fracture Toughness

为了解混凝土Ⅱ型断裂破坏过程中应力应变变化规律并确定混凝土剪切断裂韧度,制备了4组32件单边切口半边对称加载试件,利用特殊的加载方式在5 000kN压力机上对试件做了混凝土Ⅱ型断裂破坏试验,并描述了各个试件破坏时的变化情况。试验结果表明,混凝土Ⅱ型断裂破坏外加荷载—时间关系曲线、外加荷载—应变关系曲线、荷载—裂缝尖端滑移位移曲线、应变—时间关系曲线各有特点,所得单边切口半边对称加载试件能够实现混凝土的剪切断裂,且断裂韧度与初始缝长大小无关。

For purpose of revealing the change law of stress strain and determination of shear fracture toughness during the process of mode Ⅱ fracture of concrete, four groups including 32 single edge notched semi symmetric loading specimens were made. Mode Ⅱ fracture experiment were conducted by special loading device on 5000kN pressure loading machine. And then the changing process and phenomenon of specimens are described. The experiment results show that all of curves of Load Time, Load Strain and Load CTSD （crack tip sliding displacement） have its own properties; Mode Ⅱ fracture can occurred by the single edge notched semi symmetric loading specimen and shear fracture toughness has nothing to do with the initial length of crack.