聚脲基复合防渗体系设计及作用机理研究

发布时间：2018-05-10 14:47

本文选题：伸缩缝 + 裂缝　；参考：《中国水利水电科学研究院》2017年硕士论文

【摘要】：大坝、隧洞、箱涵、渡槽等水工建筑物的渗漏不仅造成水量损失,同时影响水利工程运行安全,因此水工建筑物渗漏问题亟待解决。针对南水北调穿黄隧洞和天津干线箱涵防渗工程,中国水科院结构材料研究所李炳奇教授提出聚脲基复合防渗体系(EP_DTEW工法),该体系具有适应潮湿环境、与混凝土基材粘结良好、适应伸缩缝变形、环保无毒等优点。本文基于损伤断裂力学的界面内聚力模型(CZM)有限元法,对该防渗体系的作用机理进行了仿真模拟,针对水工建筑物的裂缝及伸缩缝,研究表面涂层防渗体系结构、嵌缝材料防渗体系结构,在水压及伸缩缝变形荷载工况下破坏过程,对聚脲基复合防渗体系的材料和结构给出了设计理论及方法。界面内聚力模型应用于防渗结构的有限元计算研究在国内尚属首例。主要研究内容如下:(1)进行了聚脲基复合防渗体系结构的试验研究。分别对伸缩缝表面涂层结构及嵌缝结构进行了室内压水试验,得到防渗涂层法向位移随反向水压变化的试验数据,以及嵌缝材料表面应变随反向水压变化的试验数据,为仿真计算模型参数确定提供了依据。计算及试验结果对比分析表明,内聚力模型能够揭示防渗体系界面粘接层的破坏机理。(2)建立裂缝、伸缩缝的表面涂层防渗结构模型,该模型适用于基面产生及扩展裂缝、施工缝、低水压伸缩缝等混凝土表面柔性防渗。采用双线性内聚力模型有限元法进行剥离破坏模拟,得到表面涂层荷载—法向位移曲线,与室内压水试验数据进行比较,给出合理的界面内聚力模型参数。进而分析了表面涂层厚度与水压荷载的关系。同时,模拟了伸缩缝水压和变形混合工况下,表面涂层厚度、弹性模量和界面内聚力模型切向粘结强度对剥离长度的影响。对裂缝承受变形工况,探讨涂层弹性模量改变对于界面破坏时伸缩缝变形的影响。为水工建筑物表面涂层防渗设计的材料及结构提供了理论依据和方法。(3)建立伸缩缝的嵌缝防渗结构模型,该模型适用于承受高反向水压的伸缩缝防渗结构。采用指数内聚力模型有限元法进行剥离破坏模拟,得到嵌缝材料荷载—应变曲线,与室内压水试验数据进行比较,给出合理的界面内聚力模型参数。进而分析了嵌缝材料弹性模量、泊松比变化对水压荷载的影响,给出了嵌缝材料深度与水压荷载的关系。进一步,在嵌缝材料承受反向水压后,施加伸缩缝变形工况下,嵌缝材料深度、伸缩缝宽度变化时,界面破坏时伸缩缝变形值的变化情况。伸缩缝变形后,施加水压荷载的工况下,给出嵌缝材料深度及嵌缝材料的力学性能变化与水压荷载的关系。为嵌缝防渗体系的材料及结构设计提供了理论依据和方法。本研究为合理选择界面内聚力模型参数、准确预测聚脲基复合防渗体系界面破坏时水压和伸缩缝变形提供技术支撑,研究结果为伸缩缝防渗体系设计提供理论支持和指导。
[Abstract]:The leakage of hydraulic structures, such as dam, tunnel, box culvert and aqueduct, not only causes water loss, but also affects the operation safety of water conservancy projects. Therefore, the leakage of hydraulic structures should be solved urgently. Professor Li Bingqi of the Institute of structural materials of the China Academy of water science and Engineering has put forward the compound of polyurea based on the south to North Water Diversion Tunnel and the trunk culvert of Tianjin trunk line. The anti seepage system (EP_DTEW method) has the advantages of adapting to the wet environment, adhering to the concrete base material well, adapting to the deformation of the expansion joint and the non toxic and so on. This paper is based on the interfacial cohesion model (CZM) finite element method based on the damage fracture mechanics, and simulated the action mechanism of the seepage control system, aiming at the cracks in the hydraulic structure and the cracks and the cracks in the hydraulic structure. The structure of the anti-seepage system of surface coating, the structure of the seeping proof system, the failure process of the water pressure and the deformation load of the expansion joint are studied. The design theory and method of the material and structure of the polyurea composite anti-seepage system are given. The finite element calculation of the interface cohesive model applied to the seepage control structure is the first case in China. The main research contents are as follows: (1) the experimental study on the structure of the composite anti-seepage system of the polyurea base was carried out. The indoor pressure water test was carried out on the surface coating structure and the seam structure of the expansion joint respectively. The experimental data of the change of the normal displacement with the reverse water pressure of the impervious coating and the experimental data on the variation of the surface strain with the reverse water pressure on the surface of the seams were obtained. The calculation and test results show that the cohesive force model can reveal the failure mechanism of the interface bonding layer of the seepage proof system. (2) the model of the surface coating anti seepage structure of the cracks and the expansion joints is established. The model is suitable for the mixing of the base surface and the expansion cracks, the construction joints, the low hydraulic expansion joints and so on. With the bilinear cohesive model finite element method, the bilinear cohesive force model is used to simulate the stripping failure, and the surface coating load - normal displacement curve is obtained. The reasonable interface cohesion model parameters are compared with the indoor pressure water test data, and the relationship between the thickness of the surface coating and the hydraulic load is analyzed. The influence of surface coating thickness, modulus of elasticity and tangential bond strength of cohesive force model on peeling length under the mixed conditions of water pressure and deformation of contraction joints. The effect of the change of elastic modulus of coating on the deformation of expansion joint during interface failure is discussed. The theoretical basis and method are provided. (3) the model of the seture anti seepage structure of the expansion joint is established. This model is suitable for the seepage prevention structure of the expansion joint with high reverse water pressure. The simulation of the peeling failure is carried out by the finite element method of the exponential cohesion model, and the load strain curve of the seam material is obtained, and it is compared with the indoor pressure water test data. The influence of the elastic modulus of the joint material and the change of Poisson's ratio on the hydraulic load is analyzed, and the relationship between the depth of the seam material and the hydraulic load is given. Further, the interface failure is damaged when the seam material is subjected to the reverse hydraulic pressure to apply the depth of the joint material and the width of the expansion joint under the deformation condition of the expansion joint. The change of the deformation value of the expansion joint. After the deformation of the expansion joint, the relationship between the depth of the seam material and the mechanical properties of the sewn material and the hydraulic load is given under the condition of applying the water pressure load. This provides a theoretical basis and method for the material and structure design of the seture anti-seepage system. This study is a reasonable choice of the parameters of the cohesive force model. It provides technical support for the accurate prediction of water pressure and expansion joint deformation when the interface damage of the polyurea composite anti-seepage system is destroyed. The research results provide theoretical support and guidance for the design of the expansion joint seepage control system.

【学位授予单位】：中国水利水电科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV543

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