Numerical Realization Of Phase-field Crack Model And Its Application In Gravity Dam Engineering

Water resources are an important resource for human life and production.However,the distribution of water resources in China is seriously unbalanced due to its vast territory.The distribution and form of water resources in natural state can not meet people’s needs.Therefore,China has built a large number of water conservancy projects to achieve the purpose of redeployment of water resources in nature and flood control and disaster reduction.Among them,the large volume concrete structure(such as: gravity dam,arch dam,wharf,etc.)is especially widely used in water conservancy projects,and once the accident will cause great losses to the people’s property and safety,so the safety of water conservancy projects must be guaranteed.Since most of the water conservancy projects,especially gravity dam projects,are large volume concrete structures,a large amount of hydration heat is often generated during the construction process,and the consequent temperature load will have a significant impact on the bearing capacity and integrity of the dam.Therefore,strict temperature control and maintenance measures are required during the construction of DAMS.In addition,the dam is often subjected to huge hydrostatic pressure and many environmental factors during its operation.Moreover,many water conservancy projects in China have been in operation for a long time.In the actual construction and operation,no matter how strict maintenance and control measures are taken,there are inevitably many tiny cracks.Therefore,researchers are increasingly concerned about the initiation and propagation of cracks and their effects on the safety of dam structures.With the rapid development of computer hardware and software as well as the computational mechanics and numerical simulation method of high efficiency and repeatability advantages such as more and more accepted by people,and the numerical simulation method has produced many crack fracture damage,but inevitably have to face the crack propagation path tracking and crack the problem such as the sensitivity of the regional grid.For this reason,researchers have proposed many methods,such as grid redivision,which will greatly increase the difficulty of numerical realization and the cost of numerical calculation.Phase-field theory has been proposed to solve the above problems to a large extent.Since it was proposed,it has received a lot of attention and developed rapidly due to its advantages in crack initiation,propagation,intersection and convergence,as well as adaptability to grid density.In this paper,classical phase field theory was firstly studied,and then the unified phase field theory proposed by Wu[25] was applied to concrete and other quasi brittle materials.According to the characteristics of the governing equations of the phase field,the numerical implementation of the phase field crack model is carried out based on the powerful nonlinear solver of ABAQUS and the flexible user subroutine development function.Based on the unified phase field theory proposed by Wu and the comparative analysis of the failure experiments of classical concrete members,the advantages of the phase field theory in terms of regularization parameters and grid size are verified.Finally,the phase field model of brittle materials is adopted according to the characteristics of mass concrete structure,and the numerical simulation analysis of the gravity dam project I participated in during my postgraduate study is carried out.