P波对大体积混凝土裂缝的扩展作用研究

根据断裂动力学理论及弹性P波与裂缝相互作用的分析，利用混凝土的动态断裂韧度，研究了大体积混凝土深层或贯穿裂缝在爆炸应力波P波作用下的扩展，得到了含裂缝混凝土的安全质点振动速度，并讨论了P波频率及其入射角对安全质点振动速度的影响。结果表明，频率越低、入射角越大的应力波对混凝土裂缝的扩展作用越大，频率为10 Hz垂直入射条件下，混凝土裂缝不扩展的安全质点振动速度仅为0.95 cm/s，与水利水电工程施工组织设计手册中规定的混凝土重力坝、混凝土闸墩等大体积混凝土结构的安全振速5 cm/s有较大差距，含裂缝混凝土更加容易被破坏。

Research on crack propagation of mass concrete under effect of longitudinal wave

Based on the theory of fracture dynamics, the analysis of the interaction of longitudinal wave and crack, and the dynamic fracture toughness of concrete, the deep or the perfoliate crack propagation of mass concrete under blasting longitudinal wave was studied; the safe peak particle velocity (PPV) for concrete with crack was obtained; and the effect of the frequency and the incidence angle of longitude wave was studied. The result indicated that the lower frequency and the higher incidence angle of longitudinal wave will easily lead to the crack propagation. On condition of frequency at 10 Hz and incidence angle at 90 degree, the safe PPV of concrete with crack is 0.95 cm/s; it is lower than the value on the handbook of construction planning of hydraulic and hydroelectric projects, which is 5 cm/s for concrete gravity dam and concrete sluice board, the concrete with crack is easily been destroyed.