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考虑宽度与厚度的颗粒胶结模型理论分析

发布时间:2018-05-19 22:23

  本文选题:离散元 + 胶结模型 ; 参考:《岩土工程学报》2017年05期


【摘要】:在深海能源土、岩石风化等问题离散元模拟中,颗粒间胶结物的增减将对材料宏观力学特性有显著影响,因此需要建立考虑胶结厚度和宽度的胶结模型。针对离散元理论中粒间真实形状胶结物在粒间力作用下的刚度和强度确定问题,基于原始的Dvorkin理论,给出高精度的胶结力学响应理论解。求解中将位移函数对称化,提出一种修正位移试函数的方法,提高了二维颗粒微观胶结模型应力场的对称性和精度,经验证解答在定性和定量上符合有限元模拟结果。根据所得解答对胶结物几何参数进行了分析,讨论了胶结宽度和厚度对胶结刚度的影响,并给出了针对一般常见材料的刚度拟合公式。采用双剪统一强度理论分析了脆性和塑性胶结材料的初始破坏区位置,给出拉/压剪复合受力状态的强度包线。本文解答可方便快捷地获得胶结模型的大量力学响应信息,可作为试验数据的验证和补充,协助建立胶结物在复杂荷载作用下的破坏判据,进而建立完整的离散元胶结模型。
[Abstract]:In the discrete element simulation of deep-sea energy soil, rock weathering and other problems, the increase and decrease of intergranular binder will have a significant effect on the macroscopic mechanical properties of materials, so it is necessary to establish a cementing model considering the thickness and width of the cementation. In order to determine the stiffness and strength of the intergranular real shape cement under the action of intergranular force in discrete element theory, based on the original Dvorkin theory, a high-precision theoretical solution to the mechanical response of the cementation is presented. A method of modifying the displacement test function is proposed to improve the symmetry and accuracy of the stress field in the two-dimensional micro-cementing model of particles. It is verified that the solution accords with the finite element simulation results qualitatively and quantitatively. Based on the solutions, the geometric parameters of the cement are analyzed, the effects of the width and thickness of the bond on the stiffness of the cement are discussed, and the stiffness fitting formulas for common materials are given. The location of the initial failure zone of brittle and plastic cemented materials is analyzed by using the double shear unified strength theory and the strength envelope of the tension / compression shear composite state is given. In this paper, a large amount of mechanical response information of the cementing model can be obtained conveniently and quickly, which can be used as the verification and supplement of the experimental data, and help to establish the failure criterion of the cement under complex loads, and then to establish the complete discrete element cementing model.
【作者单位】: 同济大学土木工程防灾国家重点实验室;同济大学航空航天与力学学院;同济大学土木工程学院地下建筑与工程系;
【基金】:国家自然科学基金项目(11572228,51639008) 中央高校基本科研业务费专项资金—学科交叉类 国家重点基础研究发展计划(“973”计划)项目(2014CB046901) 同济大学土木工程防灾国家重点实验室自主课题(SLDRCE14-B-11)
【分类号】:TU521

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