Abstract
The concrete face of a rockfill dam is a long and thin slab structure, which is highly susceptible to fracture when subjected to the settlement of the dam. The study of the generation and propagation of cracks in the concrete face of rockfill dams is of great significance to dam construction and face crack prevention. In this study, the initiation and propagation of cracks in the concrete face of a rockfill dam are investigated using an extended finite element method (XFEM) and ABAQUS software for the Gongboxia concrete-face rockfill dam. A numerical model for this dam is established using a finite element method, and the face stress and deformation distributions are obtained. Based on the results, a numerical model is built to find the location where cracks are initiated in the face. The displacement of the entire model is treated as the equivalent displacement for the numerical model. XFEM is utilized throughout the modeling process to obtain the stress concentration, crack initiation, and crack propagation in the concrete face, and an analysis of crack initiation and propagation is conducted. Finally, the effects of the thickness of concrete covers and reinforcement layers on the stress intensity of crack tips are also discussed using the established numerical model, and techniques for controlling the fracturing of the concrete face have been proposed in this paper.
Highlights
Monitored data from projects show that several concreteface rockfill dams display varying degrees of cracks during construction and operation, most of which are transverse cracks in the middle or lower parts of the face [1]
A deflection of the face, which is a part of the antiseepage body of a concrete-face rockfill dam, due to a large deformation can lead to face cracking. is leads to severe leakage when the cracks penetrate and connect with one another
Cracks on the concrete face of rockfill dams can be classified into two major groups: (i) microcracks with a random distribution, which impact the compression and tensile strengths of concrete, and (ii) macrocracks, which result in anisotropy of the mechanical properties of concrete
Summary
Monitored data from projects show that several concreteface rockfill dams display varying degrees of cracks during construction and operation, most of which are transverse cracks in the middle or lower parts of the face [1]. Jin and Arson [5] used conventional finite element methods to simulate the process of concrete-face cracking based on the crack model and obtained stress distributions during the cracking process. E extended finite element method (XFEM) has been widely applied for the simulation of cracks in the concrete face of rockfill dams to overcome the deficiencies of crack propagation modeling using finite element methods. Dolbow et al [11] introduced discontinuous functions and near-tip crack functions to study crack propagation in the concrete face of rockfill dams and obtained the distribution of the crack tip intensity factor and the elements that affect its change. E Gongboxia rockfill dam in Qinghai Province, China, is analyzed in this study, for which an overall computational model yields the deformation of the concrete face, which is treated as an equivalent displacement load acting on the cracks on the concrete face of the numerical model. Based on the cracks on the concrete face in the numerical model, the propagation and evolution of cracks are studied, including stress concentration, crack initiation, and crack propagation. e effects of concrete cover thickness and reinforcement layers on the stress intensity of crack tips are discussed with the established numerical model
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