【作者】 韩世栋；

【导师】 顾冲时；

【作者基本信息】 河海大学 ， 水工结构工程， 2007， 硕士

【摘要】 本文针对带缝坝的安全问题，结合大型有限元分析软件ABAQUS，以大坝实测资料为基础，采用相关数学、力学理论和方法，对带缝坝的安全性分析及预警方法进行了研究，其主要的研究内容有：(1)较为系统地分析了混凝土坝裂缝产生的原因，基于粗集和模糊神经网络理论，研究了混凝土坝裂缝成因挖掘的实现方法。(2)从裂缝对混凝土坝强度、稳定、耐久性及整体性等影响方面，研究了裂缝对大坝安全的危害性。(3)研究了温度场仿真分析基本原理及其在ABAQUS中计算温度场的方法；对比分析了裂缝的各种有限元分析模型，在此基础上，二次开发了ABAQUS，结合工程实例，综合评价了裂缝对大坝的危害性。(4)基于实测资料，应用小波分析理论，提取了运行期裂缝的时效变形，据此研究了裂缝开度随时间的演变规律；综合应用灰色和神经网络理论，建立了裂缝开度的组合预测模型；此外，对裂缝的失稳判据和监控指标进行了研究。(5)在对裂缝的演变规律、裂缝开度的预测模型以及裂缝失稳判据研究基础上，探讨了裂缝的安全预警和拟定预警指标的方法，并用置信区间法拟定了裂缝开度的预警区间。更多还原

【Abstract】 Combining with prototype observation data of the dam and ABAQUS which is a general-purpose finite element analysis software, the safety analysis and early-warning method for the dams with cracks are studied by using mathematical theories and mechanical methods. The main contents are as follows.(1) The cause of concrete dam’s crack is systematically analyzed. Combining rough set theory with fuzzy neural network, the realized method of cause mining of concrete dam’s crack is presented.(2) The harmfulness of the cracks is studied from the strength, stability, duration and entirety of the concrete dams.(3) The simulation theory of temperature field and the calculative method of temperature field in ABAQUS are studied, and the various finite element models of concrete dam’s crack are contrasted. On this basis, the ABAQUS is developed and the jeopardizing degree is comprehensively evaluated by living example.(4) Combining with prototype observation data, the wavelet theories is applied to distill secular component of crack. Then the regularity of evolution is studied. A nonlinear assembled prediction model is established by using the theories of the gray and neural network. In addition, the destabilizing criterion and monitoring index of crack are studied.(5) Combining with the regularity of evolution, the prediction model and the destabilizing criterion of crack, the security early-warning method and how to confirm early-warning index are discussed.更多还原