基于裂缝口开度的水工混凝土结构裂缝性态监控方法

针对复杂工况下带缝水工混凝土结构的裂缝扩展判据难以用于工程实际,且常规有限元法扩展法需不断进行网格重建的问题,推导了包含裂尖效应的渗流—应力耦合的扩展有限元模型,以此分析并建立了裂缝口开度与宏观裂尖开度在裂缝扩展全过程的关系,提出了基于粘着力的宏观裂尖判别法,并从数值分析角度验证了宏观裂尖开度临界值的无尺寸效应,利用其与裂缝口开度的关系建立了水工混凝土结构裂缝起裂、稳定扩展、失稳扩展全过程的监控方法,最终通过算例验证了该方法的合理性。

Monitoring Method of Crack Behavior in Hydraulic Concrete Structure Based on Crack Mouth Opening Displacement

For the difficulty of applying classical fracture criteria to the actual engineering, and the computational cost due to re-meshing the geometry discontinuities in simulating crack growth by traditional FEM. In this paper, the XFEM model considering near-tip singular behavior is derived under the effect of hydro-mechanical (HM) interaction. And then it establishes the relationship between the crack mouth opening displacement (CMOD) and the crack-tip opening displacement (CTOD) in the whole process of crack extension. A method of determining macro crack-tip is proposed based on cohesive force. At the same time, the critical value of CTOD is investigated and proved to be a material parameter from the perspective of numerical analysis. Based on the relationships between CMOD and CTOD, the safety monitoring method of crack extension in hydraulic concrete structure is established during the whole cracking process related to crack initiation, stable expansion and unstable expansion. Finally, the proposed method is verified by the numerical calculation.