坝基界面在非线性水压力驱动下的非线性断裂过程模拟

发布时间：2018-03-10 14:39

  本文选题：混凝土坝　切入点：水力劈裂　出处：《工程力学》2017年04期 　论文类型：期刊论文

【摘要】：基于多边形比例边界有限元法和粘聚裂缝模型提出了混凝土坝坝基界面在随缝宽非线性变化的水压力驱动下的非线性断裂数值模型。混凝土和基岩采用多边形比例边界单元模拟,界面裂缝的断裂过程区采用粘性界面单元模拟。因为界面裂缝总是处于复合断裂模态,故同时引入了法向和切向的界面单元,且考虑了裂纹面作用有法向和切向任意荷载时的应力强度因子求解。以裂尖为原点,裂尖附近的位移场和应力场在径向上解析求解,在环向具有有限元精度。因此无需在裂尖附近加密网格或采用富集技术即可求得高精度的解。对于界面断裂,可模拟出与两种材料差异性相关的非1/2奇异性。断裂过程区的水压力随缝面宽度变化,采用指数函数的形式进行表征,通过参数调整可实现不同分布的水压力的模拟。水压力与粘聚力考虑为与裂缝宽度相关的组合函数,便于非线性迭代的实现。结合多边形网格生成和重剖分技术,可方便地模拟界面裂缝在水力驱动下的扩展过程。算例研究表明了该文模型的有效性,从中也可看出考虑缝内水压及其具体分布形式对研究坝的稳定性具有重要影响。
[Abstract]:Based on polygonal proportional boundary finite element method and cohesive crack model, a nonlinear fracture numerical model for the interface of concrete dam foundation driven by water pressure with nonlinear variation of joint width is presented. The polygon ratio is used for concrete and bedrock. Example boundary element simulation, The viscous interface element is used to simulate the fracture process of the interface crack. Because the interface crack is always in the composite fracture mode, both normal and tangential interface elements are introduced at the same time. The stress intensity factor is solved by taking the crack tip as the origin, and the displacement field and stress field near the crack tip are analytically solved in radial direction. It has finite-element accuracy in the circumferential direction, so it is not necessary to encrypt the mesh near the crack tip or to obtain the high-precision solution by using enrichment technique. The non-#number0# singularity related to the difference between the two materials can be simulated. The water pressure in the fracture process varies with the width of the fracture surface and is characterized by exponential function. Different distribution of water pressure can be simulated by adjusting parameters. Water pressure and cohesive force are considered as combination functions related to crack width, which is convenient for the realization of nonlinear iteration. The numerical example shows the validity of the model, from which it can be seen that considering the water pressure in the joint and its specific distribution form have an important influence on the stability of the dam.
【作者单位】： 大连理工大学建设工程学部;中国水利水电科学研究院岩土所;
【基金】：国家自然科学基金项目(51009019,51579033) 中央高校基本科研业务费专项资金项目(DUT14LK40) 中国博士后基金特别资助项目(2013T60283) 国家自然科学青年基金项目(51109134)
【分类号】：TV642;TV223
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本文编号：1593775