考虑土体裂缝特性的XFEM复合破坏准则及ABAQUS实现

    XFEM composite failure criterion and ABAQUS implementation considering soil crack characteristics

    • 摘要: 在各类土工结构中存在大量张拉-剪切复合裂缝的问题,然而由于土体材料的复杂特性,传统数值方法难以对土体裂缝的复合破坏过程进行准确和精细化的模拟。本文在充分考虑土体裂缝特性的基础上,采用了一种土体模量相关的非局部加权平均应力作为裂缝演化判别依据,在ABAQUS软件中通过子程序二次开发实现了可统一描述土体的张拉-剪切复合破坏的判别准则,并结合扩展有限单元法(XFEM)模块模拟土体复合裂缝的演化过程。与ABAQUS自带方法的对比表明,本文所提方法对于土体裂缝演化过程的模拟更为真实,能充分反映土体材料特性的影响。最后对一个三点弯梁破坏案例和一个边坡坡顶堆载滑裂破坏案例进行了模拟分析,验证了所提方法的有效性和正确性,证明本文所提方法能较为准确地再现边坡破坏过程中裂缝的产生和扩展及最终贯穿的过程,为边坡破坏全过程精细化模拟提供了一种有效的途径。

       

      Abstract: There are a large number of tension-shear composite cracks in various geotechnical structures. However, due to the complex characteristics of soil materials, it is difficult for traditional numerical methods to accurately simulate the composite failure process of soil cracks. Considering the characteristics of soil cracks, this paper adopts a non-local weighted average stress related to soil modulus as the basis for the discrimination of crack evolution. In ABAQUS software, through the secondary development of a subprogram, the discrimination criterion of the composite failure of soil tension-shear is realized. Combing the extended finite element method (XFEM) module, the evolution process of composite cracks in soil is simulated. The comparison with ABAQUS method shows that the proposed method is more realistic in simulating soil fracture evolution and can fully reflect the influence of soil material characteristics. Finally, the effectiveness and correctness of the proposed method are verified by simulation analysis of a three-point bending beam failure case and a slope top load sliding crack failure case. It is proved that the proposed method can accurately reproduce the generation, expansion and final penetration process of cracks in the slope failure process, which provides an effective way for the fine simulation of the whole process of slope failure.

       

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