Abnormality diagnosis of cracks in the concrete dam based on dynamical structure mutation

Abstract

A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the downstream face of a concrete gravity arch dam is analyzed with the proposed method. Two distinct mutations are discovered to indicate that the abnormality diagnosis of cracks in the concrete dam is achieved dynamically through this method. Furthermore, because it can be directly utilized in the measured crack opening displacement series to complete abnormality diagnosis, it has a good prospect for practical applications.dynamical structure mutation, cracks in the concrete dam, method of the fuzzy cross-correlation factor exponent in dynamics, abnormality diagnosis of cracks Citation:Gu C S, Li Z C, Xu B. Abnormality diagnosis of cracks in the concrete dam based on dynamical structure mutation.

Order typical small probability diagnosis method of concrete dam crack behavior abnormality

“…李雪红等人 [20] 认为裂缝的时效变形反映了裂缝的稳 定性和转异特征, 采用相空间重构技术对时效变形 重构相平面, 由此识别裂缝的转异点, 确定裂缝转异 发生的时间. Gu 等人 [21] 提出了混凝土坝裂缝转异诊 断的动力学模糊互相关因子指数法, 实现了混凝土 坝裂缝的动态转异诊断, 此外, Li 等人 [22] [23] 在 1963 年提出的, 在金 属裂缝诊断领域得到了成功应用. 一些学者将裂缝 尖端张开位移 CTOD 理论, 引入到混凝土结构裂缝 的诊断分析中, 通过不同尺寸混凝土构件的试验, 得 出混凝土结构的临界裂缝尖端张开位移 CTOD c 与试 件尺寸无关的结论, 进一步的研究表明, 临界裂缝尖 端张开位移 CTOD c , 可作为控制混凝土断裂的重要 材料参数 [24] .…”

Research advance in failure risk and local strength failure for high arch dams

“…Fu et al [143] studied the possible cracking of Xiaowan high arch dam under temperature-stress coupling action according to the monitoring data, which can provide the scientific basis for cracking prevention. Besides, Bao et al [144,145] and Gu et al [146] studied the variation of existing crack in dam and gave some advises for dam safety. And the researches of Liu et al [147] and Lei et al [148] on monitoring of crack initiation and expansion were from microscopic and macroscopic views respectively.…”

Inferring rules for adverse load combinations to crack in concrete dam from monitoring data using adaptive neuro-fuzzy inference system

“…From Figure 8 and Table 1, we can observe that with regard to the crack opening displacement, low reservoir water level and low temperature are the most adverse load combination, and high reservoir water level and low temperature are also a significantly adverse load combination. In fact during the dam operations, the dam suffered from two load combinations of high temperature and low water level and three load combinations of low temperature and low water level, which made the crack irreversible change during the end of 1976 to early 1977 [4,5,14]. Therefore, in order to achieve the stability of the crack and the safety of the dam, we should control the reservoir at the medium reservoir water level, i.e.…”

“…The integrity and safety assessment of concrete dams is an important engineering task, in which cracks are one of the main symptoms and of significant negative influence [1][2][3][4]. The formation and propagation of cracks in concrete dams are largely affected by the combinations of various loads, such as hydrostatic loads, temperature loads, and dynamic earthquake loads [1][2][3][4][5][6][7], during the dam operations.…”

“…The formation and propagation of cracks in concrete dams are largely affected by the combinations of various loads, such as hydrostatic loads, temperature loads, and dynamic earthquake loads [1][2][3][4][5][6][7], during the dam operations. Different load combinations may have different influences on the crack behaviors.…”