FEM-SBFEM联合计算库水—坝体—无限地基系统的地震响应

发布时间：2018-01-15 20:40

本文关键词：FEM-SBFEM联合计算库水—坝体—无限地基系统的地震响应　出处：《沈阳工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：库水-大坝-无限地基系统的相互作用问题是重力坝在地震荷载作用下坝体动力响应的重要因素之一,研究坝体在地震荷载作用下的动力响应是混凝土大坝安全评估的重要基础。基于比例边界有限元法(the Scaled Boundary Finite Element Method-SBFEM)计算上游坝面库水压力、基于无限单元法考虑无限地基辐射阻尼的影响,计算库水-混凝土重力坝-无限地基系统不同工况下的地震响应。基于SBFEM方法计算混凝土坝面动水压力,并将其与有限元法联合计算库水-坝体-无限地基系统的地震响应;利用大型有限元计算软件Abaqus基于无质量地基模型和无限地基模型联合SBFEM分别计算了不同地基弹性模量以及非均匀地基条件下库水-坝体-无限地基系统的地震响应,并将计算结果进行对比分析,得到一些有意义的结论;然后利用SBFEM与Abaqus的联合计算,探讨了库水-坝体-无限地基系统在不同地基弹性模量,不同阻尼比以及地基非均匀工况下坝体的地震动力响应及损伤区域,使其对坝体建设和抗震安全评价具有一定的参考价值。最后通过对比计算得到以下结论:在弹性情况下,随着地基弹性模量的增加,坝体的动力响应逐渐增大,由此可见随着地基刚度的增加,对坝体的影响也变大;在弹塑性情况下,地基弹性模量大于坝体的弹性模量(无质量地基模型与无限地基两种模型)时,坝踵处均出现损伤,坝体的中间薄弱区则出现损伤区域并且贯穿至上游坝面;而小于坝体的弹性模量时,坝踵处则无损伤,但坝体的中间薄弱区也出现损伤区域并且贯穿至上游坝面;在弹性情况下,与无限地基模型相比,无质量地基模型计算所得的坝体位移以及应力分布基本相同但峰值明显增大;在弹塑性损伤情况下,非均匀地基条件下出现的损伤区域略小于均匀地基的损伤区域,并且非均匀地基初始损伤时间也早于均匀地基的,特别是无质量地基模型(非均匀地基)损伤区域出现的时间更早一些。
[Abstract]:The interaction between reservoir, dam and infinite foundation system is one of the important factors for the dynamic response of gravity dam under earthquake load. To study the dynamic response of dam body under earthquake load is an important foundation of concrete dam safety assessment. The Scaled Boundary Finite Element method-SBFEMs calculate the upstream dam surface water pressure. The effect of radiation damping on infinite foundation is considered based on infinite element method. The seismic response of reservoir-concrete gravity dam-infinite foundation system under different working conditions is calculated. The dynamic water pressure on concrete dam surface is calculated based on SBFEM method. The seismic response of the system of reservoir water dam body and infinite foundation is calculated in conjunction with the finite element method. Based on the massless foundation model and infinite foundation model combined with SBFEM, the large finite element calculation software Abaqus is used to calculate the elastic modulus of different foundation and non-uniform foundation respectively. Seismic response of limited foundation system. The results are compared and analyzed, and some meaningful conclusions are obtained. Then, by using SBFEM and Abaqus's joint calculation, the elastic modulus of reservoir, dam and infinite foundation system in different foundation is discussed. The seismic dynamic response and damage area of dam body under different damping ratio and non-uniform working condition of foundation. It has certain reference value for dam construction and seismic safety evaluation. Finally, through comparison and calculation, the following conclusions are obtained: in elastic case, with the increase of elastic modulus of foundation, the dynamic response of dam body increases gradually. It can be seen that with the increase of foundation stiffness, the influence on dam body also becomes greater. When the elastic modulus of the foundation is larger than the elastic modulus of the dam body (both the massless foundation model and the infinite foundation model), damage occurs at the dam heel. The weak area in the middle of the dam body is damaged and runs through the upstream dam surface. When the elastic modulus of the dam is less than that of the dam, there is no damage at the heel of the dam, but the weak area in the middle of the dam is also damaged and runs through to the upstream surface of the dam. In the elastic case, compared with the infinite foundation model, the displacement and stress distribution of the dam body calculated by the massless foundation model is basically the same but the peak value is obviously increased. In the case of elastic-plastic damage, the damage area under the condition of non-uniform foundation is slightly smaller than that of the uniform foundation, and the initial damage time of the non-uniform foundation is earlier than that of the homogeneous foundation. In particular, the damage zone of the non-uniform foundation model appeared earlier.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV698.13

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