Subjects: Mechanics >> Basic Mechanics submitted time 2023-04-24 Cooperative journals: 《应用力学学报》
Abstract： Discontinuous deformation analysis(DDA)is a numerical method that computes the mechanical behaviors of discrete deformable-block systems,which can be used to simulate the cracking failure of rock by the sub-block method.Considering the similarity of morphology between Voronoi polygonal particles and rock mineral grains shapes at the mesoscale,a generation method of Voronoi particle element model based on random circles is proposed.By simulating the cracking failure process of intact rock disc and rock discs with a pre-existing crack,the feasibility of simulating rock cracking failure with the Voronoi sub-block element DDA is verified.Results indicate that the rock disc shows higher integral strength with the decrease of the number of sub-block elements.With the increase of the element number,the crack initiation position is closer to that in reality,and the failure path gets clearer.With a large-enough number of the elements,the cracking failure simulation results of the discs with different pre-existing crack inclinations are highly consistent with the experimental results,and the influence of the center machining hole in the disc on the failure path can be accurately captured as well.The Voronoi sub-block element DDA can effectively simulate the cracking failure process of rock,which provides conditions for the further simulation of rock cracking failure with Voronoi particle elements.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： This paper fully reviews the progress in the research and application of discontinuous deforma-tion analysis ( DDA) and numerical manifold method (NMM) in the field of rock mechanics and engi-neering problem simulations. First , the research status of related theories and algorithms is expounded , in-cluding the solution to the problem of spurious rotational volume expansion and energy loss in DDA, thesub-block element DDA method and the nodal-based DDA method for fracturing failure simulation，andthe development of particle DDA method.Research on fracturing simulation capability and dual cover sys-tems of NMM ，as well as development of the meshless NMM and particle NMM are also included.Re-search on simplex integration，high-order method，material constitutive model，and explicit and parallelcomputing are also involved.Moreover , research on contact-related problems is specially discussed.Subse-quently , this paper expounds on the representative research and application works of DDA and NMM inthe engineering fields of rock mass slope instability and rockfall ，deformation and failure of undergroundrock mass structure，stress wave propagation and rock blasting，seismic breakage and instability of rockmass structure，and rock mass anchoring.On this basis , the main problems and challenges of the researchand application of DDA and NMM are abstracted and discussed ，including the calculation control parame-ters，calculation efficiency，multi-physics fields，three-dimensional methods，and the commercial devel-opment of the programs，and corresponding countermeasures are proposed.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： To study the mechanical interaction process and mechanism between rock bolt and rock mass inthe pullout experiment , an interface coupling algorithm between the rock bolt and rock mass is introducedinto the discontinuous deformation analysis ( DDA) method, and the slip debonding of the rock bolt in therock mass is represented by multi-linear bond-slip interface model.By comparing the simulation resultswith the experimental results , the parameters of the tri-linear and four-linear bond slip interface modelsfrom literatures are revised , and the correctness and applicability of the proposed interface coupling algo-rithm are validated.Through DDA simulations of rock bolt pullout based on the multi-linear bond-slip in-terface models with revised parameters , the pulling force and displacement relationship, and the distribu-tion and variation rules of the interface shear stress and bolt axial force under dfferent pulling force levels are studied. The influence of the rock bolt modulus on the rock bolt pullout mechanical response is also in-vestigated.
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