基于石膏材料的小结构重力坝损伤本构模型研究

Damage of Gypsum Material Gravity Dam Model

大坝模型试验的模型材料力学性能是试验成功与否的关键影响因素。基于石膏模型材料基本力学性质和混凝土材料基本相似的实际情况,考虑石膏模型材料的孔隙率,在能量损伤理论模型的基础上,结合工程规范,建立了石膏模型材料的受拉损伤本构模型。同时,分析了模型材料应变率对材料峰值应力的影响,引入动应力提高系数,并给出了与应变率相关的模型材料受拉损伤本构模型。利用该本构模型模拟了动荷载下石膏模型重力坝的破坏过程,并与模型试验结果进行对比。结果表明:数值模拟得到的重力坝开裂破坏的位置、形式与模型试验结果较为接近。

Mechanical property of dam model material is the critical factor to success. Since the fundamental mechanical property of GMM （gypsum model material） is basically similar with that of concrete, so based on energy damage model, a tensile damage constitutive model for GMM was established by taking into account the porosity of GMM and engineering specifications. In addition, a quantitative analysis of the effect of model material strain rate on the GMM peak stress was conducted, a dynamic stress increase factor was introduced. Thus a tensile damage constitutive model related with strain rate for GMM was obtained. Using this constitutive model, the failure process of gravity dam gypsum model subiected to dynamic loading was simulated and its results were compared with experimental one. Results show that the crack damage position and crack pattern of gravity dam from numerical simulation are close to that from model experiment.