内容摘要：针对300m级拱坝可能出现上游坝面裂缝的问题，提出了增设柔性防渗层的防渗方案。根据300m级拱坝的受力特点，选择了以喷涂聚脲为主的3种复合防渗方案，并进行了抗折试验、黏结强度试验、高水头迎水面抗渗试验及仿真模型试验。为了检验现场施工的可行性，进行了现场工艺性试验，选定了粘贴3mm厚GB柔性板+喷涂4mm厚聚脲和直接喷涂7mm厚聚脲2种防渗方案。试验结果表明：当聚脲厚度与缝宽之比大于0.57时，聚脲可以承受3MPa的水压力不渗漏；喷涂聚脲技术可以满足大面积、快速施工的要求，聚脲与GB板的配合使用，避免了混凝土开裂聚脲变薄，增加了聚脲的防渗效果。

       关键词：300m级拱坝；防渗；聚脲；仿真模型试验；GB柔性板

       中图分类号：TV441　　                   文献标识码：A

       Simulation Model Test of Spraying Polyurea as Anti-seepage Coat on Arch Dams over 300m and its Application on Xiaowan Project

       sun zhiheng1      Yunjianqing2

       1. Department of Structures and Materials, China Institute of Water Resources and Hydropower Research，Beijing 100038

       2.Kunming Hydropower Investigation Design & Research Institute，CHECC, Kunming 650051

       Abstract: In order to enclose the cracks in upstream surfaces of arch dams over 300m, the method of adding flexible anti-seepage coat is put forward in this paper. Three compound anti-seepage schemes focusing on spraying polyurea are selected based on stress characteristics of 300m arch dams. At the same time, bending test, bond strength test, anti-seepage test by high water pressure as well as stimulation model test are carried out. The test results indicate that ployurea coat can resist water pressure over 3Mpa while the ratio of ployurea thickness and concrete crack is 0.57.  Field technique test is also executed to verify the feasibility of on-site construction. In the field test, two schemes are selected, one is combining 3mm GB flexible board and 4mm polyurea coat, the other is spraying 7mm polyurea coat. The field test results indicate that spraying polyurea technology can meet the requirements for large areas and quick construction. The compound application for polyurea coat and GB board can not only avoid the thinning of polyurea but also improve the anti-seepage effect. This scheme has been applied successfully on the upstream surface of Xiaowan arch dam.