基于损伤理论的混凝土裂缝扩展研究

Study of Crack Propagation of Concrete Based on Damage Theory

采用Loland损伤模型,推导了Ⅰ-Ⅱ复合型裂缝尖端区域的损伤断裂区域方程,得到各损伤区形状及范围;并提出了基于缝端损伤区域的裂缝发展的双D损伤判据和双R损伤半径判据;利用有限元软件建立并模拟Ⅰ-Ⅱ复合型裂缝在起裂荷载以及失稳荷载作用下损伤区域,将有限元计算结果与理论结果进行对比分析,以验证本文方法的合理性;将损伤区理论应用于工程实例中,计算出带裂缝重力坝的起裂损伤区以及失稳损伤区,分析了坝体裂缝在相应荷载作用下的安全性.

According to Loland damage model,the damage region equation of Ⅰ-Ⅱ mixed mode cracks in the crack tip and the size and shape of the damage area of various kinds of damage zones are obtained.The double D and double R damage criterion,which is used to describe the damage development of concrete crack,is put forward based on the essential concept of damage mechanics.Ⅰ-Ⅱ mixed mode are established which is based on finite element software to get the damage zone under the initiation load and instability load;and then the calculated results are compared with the theoretical result in order to verify the rationality of this method. Finally,the damage zone theory is applied to the case study for calculating the crack initiation damage zone and unstable damage zone of cracked gravity dam,so as to analyze the safety of dam cracks under corresponding loads.