A new Method for Measuring Mode-I Dynamic Fracture Toughness of Rock under Blasting Loads
A new Method for Measuring Mode-I Dynamic Fracture Toughness of Rock under Blasting Loads
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DOI：
10.1007/s40799-016-0093-x
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发表时间：
2016-04
影响因子：
1.6
通讯作者：
Z. Zhu;W. Xu;R. Feng
中科院分区：
文献类型：
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作者：
Z. Zhu;W. Xu;R. Feng
利用炸药进行爆破开挖的方法在采矿业和采石业中仍然广泛应用，因此爆破荷载作用下岩石的动态断裂韧性是岩石动力学最受关注的课题之一。本文利用雷管和具有I型裂纹的水泥砂浆试件进行了爆破试验。裂纹萌生时间由信号调节器记录的应变信号确定。通过孔附近两个应变片测得的应变得到作用在孔上的压力，然后利用ANSYS软件在后续的数值计算中将该压力作为孔的动态边界条件。计算裂纹尖端张开位移，并将其应用于裂纹尖端动态强度因子KI的测定，从而得到KI随时间的变化曲线。根据裂纹萌生时间确定动态韧性。
Blasting excavation method by using explosive is still widely applied in mining and quarrying, and therefore, rock dynamic fracture toughness under blasting loads is one of the most concerned subjects in rock dynamics. In this paper, blasting experiments by using detonators and cement mortar specimens with a mode-I crack were conducted. The crack initiation time was determined by the strain signal recorded by a signal conditioner. The pressure acting on the hole was obtained by the strains measured from the two strain gauges near the hole, and then the pressure was applied as the dynamic boundary condition of the hole in the subsequent numerical calculation by using ANSYS code. The crack tip open displacements were calculated and applied in the determination of crack tip dynamic intensity factorsKI, and accordingly the curve ofKIversus time was obtained. The dynamic toughness was determined according to the time of crack initiation.