300m级拱坝喷涂聚脲防渗仿真模型试验及应用

针对300 m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300 m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3 mm厚GB板+喷涂4 mm厚聚脲和直接喷涂7 mm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3 MPa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,克服了混凝土开裂而聚脲变薄的缺陷,提高了聚脲的防渗效果。

Simulation model test of spraying polyurea as anti-seepage layer on 300-m high arch dams and its application

The method of adding a flexible anti-seepage layer is put forward as a solution to the problem of cracks in upstream surfaces of arch dams over 300 m high.Three compound anti-seepage schemes using sprayed polyurea as the main body are chosen based on stress characteristics of 300 m arch dams.At the same time,bending tests,bond strength tests,anti-seepage tests at high water pressure,and simulation model tests were carried out.In order to check the possibility of field construction,a field technological test was conducted.Two schemes were selected,one combining a 3 mm GB flexible plate and a 4 mm polyurea coat,and the other consisting of the spraying of a 7 mm polyurea coat.The test results indicate that the ployurea layer can resist water pressure over 3 MPa while the ratio of ployurea thickness and the concrete crack is greater than 0.57.Spraying polyurea technology can meet requirements for large areas and quick construction.The compound application for the polyurea coat and GB board not only avoids the thinning of polyurea by a concrete crack but also improves the anti-seepage effect of polyurea.