中文摘要：

通过混凝土Ⅰ-Ⅱ复合型拉剪断裂试验设计及成果分析,基于双K断裂准则,分别计算了混凝土Ⅰ-Ⅱ复合型拉剪断裂试件失稳断裂破坏时考虑断裂过程区影响的临界有效裂缝长度ac及其对应的应力强度因子KⅠ和KⅡ,建立了考虑断裂过程区影响的混凝土Ⅰ-Ⅱ复合型拉剪断裂判据,并用二次抛物线拟合了其临界曲线.与不考虑断裂过程区影响的判据临界曲线相比,考虑断裂过程区的影响,可提高裂缝稳定性计算的安全度,降低材料抗裂性能的要求.

英文摘要：

Based on the double-K fracture criterion,the critical effective crack length ac and the corresponding stress intensity factors KⅠ and KⅡ of Ⅰ-Ⅱ mixed tensile-shear fracture specimens at failure were calculated through the design and the analysis of tensile-shear fracture tests on Ⅰ-Ⅱ mixed model of concrete. A new Ⅰ-Ⅱ mixed tensile-shear fracture K criterion was established considering the influences of fracture process zone. The critical curve of the new fracture K criterion was fitted with the quadratic parabola. Compared with the critical curve without consideration of the influences of fracture process zone,the critial curve of the proposed model indicate that the safety of calculating the stability of cracks is improved and the requirements of crack-resistant behaviors of material are reduced.