水工混凝土弥散型裂缝数值模型中开裂判据的研究

STUDY ON HYDRAULIC CONCRETE CRACKING CRITERION IN SMEARED CRACK NUMERICAL MODEL

重大水利工程中,混凝土结构多处于高水压环境,坝体或多或少存在着裂缝,然而大部分开裂的混凝土坝仍能够安全运行,从而引申出是否可以允许混凝土结构出现裂缝,多大的裂缝才不至于引起破坏,以及用怎样一个合理的指标来对混凝土开裂程度进行描述评判的问题。该文以等效塑性应变表征混凝土弥散型裂缝模型数值模拟中的开裂破坏,通过混凝土单轴拉伸数值模拟,并根据试验资料及相关文献,建立了等效塑性应变与主拉应变、裂缝宽度之间的关系,得到对应于"有害裂缝"的等效塑性应变值。将方法和成果运用到混凝土重力坝的开裂研究中,具有较好的实际工程意义。

In major hydraulic engineering, concrete structures are usually in the environment of high water pressure, and the dam has more or less cracks. However, most cracking concrete dams are still able to operate safely, which gives rise to the problems of whether or not to allow the appearance of cracks in concrete structures, how wide cracks that will not cause damage, and what a reasonable index can be used to describe and judge the extent of concrete cracking. In this paper, equivalent plastic strain represents concrete cracking damage in a smeared crack numerical model. Through the numerical simulation of concrete uniaxial tensile and based on experimental data and related literatures, the relationship between the equivalent plastic strain and principal tensile strain and crack width was established, and the value of equivalent plastic strain corresponding to 'harmful cracks' was obtained. The method and results are applied to the study on the cracking for a concrete gravity dam, which has a good practical engineering significance.