突变理论在地质力学模型试验失稳判据中的应用

发布时间：2018-05-23 18:58

本文选题：尖点突变理论 + 有限元　；参考：《工程科学与技术》2017年04期

【摘要】：地质力学模型试验是研究高坝工程稳定安全性的重要方法之一,如何较准确的通过测试结果建立大坝失稳判据,判断坝与地基的失稳破坏过程,得到综合稳定安全系数,是地质力学模型试验的关键技术问题。本文由突变理论及其相关性质,选用较为成熟的尖点突变模型及其标准势函数公式,推导出相应的失稳突变判别式,建立基于尖点突变理论的失稳判据,并通过相关算例进行有限元分析,依据计算成果的变位超载系数关系,提出超载安全系数,并与有限元塑性区贯通、计算不收敛等失稳判据对比分析,印证尖点突变模型失稳判据的可靠性和适用性。再将其应用于丹巴水电站地质力学模型试验中,试验结果给出了闸坝在正常蓄水位和降强之后超载作用下的位移场,获得了闸坝的变形及分布特征,揭示了裂缝发展的全过程及其破坏机制,得到降强系数为1.18,超载系数为1.8~2.0,确定了闸坝整体稳定安全系数为2.12~2.36。根据尖点突变理论,由试验测试成果建立相关失稳判据,据此提出破坏过程及综合稳定安全系数,并与常规地质力学模型试验分析成果进行对比,分析结果验证了基于地质力学模型试验测试成果的尖点突变模型失稳判据的合理性。
[Abstract]:The geomechanical model test is one of the important methods to study the stability safety of high dam engineering. How to establish the dam instability criterion accurately through the test results, judge the failure process of dam and foundation, and obtain the comprehensive stability safety factor. It is a key technical problem in the model test of geomechanics. Based on the catastrophe theory and its related properties, the more mature cusp catastrophe model and its standard potential function formula are used to deduce the corresponding unstable catastrophe discriminant, and the instability criterion based on the cusp catastrophe theory is established. The safety factor of overload is put forward according to the relation of the displacement and overload coefficient of the calculation results, and compared with the failure criterion of finite element, such as the plastic zone, the calculation of non-convergence, and so on. The reliability and applicability of the instability criterion of the cusp catastrophe model are verified. Then it is applied to the geomechanical model test of Danba Hydropower Station. The result of the test gives the displacement field of the gate dam under the action of the normal water level and the overloading after the drop of strength, and the deformation and distribution characteristics of the dam are obtained. The whole process of fracture development and its failure mechanism are revealed. The strength reduction coefficient is 1.18 and the overload coefficient is 1.82.0.The overall stability safety factor of the dam is determined to be 2.12 ~ 2.36. According to the cusp catastrophe theory, the relevant instability criterion is established from the test results, and the failure process and the comprehensive stability safety factor are put forward, and the results are compared with the results of the conventional geomechanical model test and analysis. The analysis results verify the rationality of the instability criterion of the cusp catastrophe model based on the test results of the geomechanical model test.
【作者单位】：四川大学水利水电学院水力学与山区河流开发保护国家重点实验室;成都理工大学博物馆;
【基金】：国家自然科学基金资助项目(51379139;51409179)
【分类号】：O192;TV64

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