裂纹方向压应力对混凝土断裂过程区尺度的影响

针对平行于裂纹方向作用有压应力的无限大板I型中心裂纹问题，基于Muskhelishvil应力函数得出的裂纹尖端最大拉应力和最大压应力确定了修正的莫尔强度理论的适用条件；推导了裂纹尖端微裂区临界值的解析表达式；采用幂函数模型描述的拉应变软化模型，确定了断裂过程区临界值。结果表明应用修正的莫尔强度理论评估混凝土I型裂纹尖端微裂区和断裂过程区尺度是合理的；微裂区和断裂过程区尺度随平行于裂纹方向压应力作用的增加而增加。

Influence of Compression in the Crack Direction on Concrete FPZ Size

Based on the maximum tensile stress and the maximum compressive stress obtained by Muskhelishvil stress function at the crack tip, the applicable condition of the modified Mohr strength criterion was determined for Griffith mode I crack problem in which the compressive stress is applied in the crack direction. The analytical expression of critical characteristic micro crack zone size ahead of the crack was derived, and the critical fracture process zone (FPZ) size was yielded out with a power exponent tensile strain softening model of concrete. The results show it is accessible that the modified Mohr strength criterion can be used to predict the micro crack zone sizes and FPZ sizes of Griffith mode I crack problem and moreover, the micro crack zone sizes and FPZ sizes increase with the applied compressive stresses in the crack direction.