深覆盖层上面板堆石坝的圆弧型防渗墙

覆盖层的防渗设施大都采用混凝土防渗墙。防渗墙在靠近两岸部位及靠近顶部常存在较大的拉应力，易导致混凝土开裂并产生渗漏，影响大坝的安全。采用平面上防渗墙轴线呈圆弧型的防渗墙来改善防渗墙的应力性状，并用三维有限元法数值分析对圆弧型防渗墙与直线型防渗墙的应力变形性状进行分析比较，论证了以圆弧型防渗墙替代直线型防渗墙的技术合理性，建议面板堆石坝坝基防渗采用圆弧型防渗墙更为有利。

Arc type diaphragm wall for concrete face rockfill dam built on deep alluvium deposit

A concrete diaphragm wall is always used to prevent the seepage through the deep alluvium deposit for conerete face rockfill dam built on it. The tensile stress distributed the zones near by the both riversides and the top zone of the concrete diaphragm wall are usually big and sometimes are even larger than the tensile strength of concrete, that usually leads to cracking of diaphragm wall which decreases the safety of diaphragm wall and dam. In order to solve this complex problem, a new idea-- arc type diaphragm wall is suggested. Comparison between the stress-deformation behavior of arc type diaphragm wall and that of plane type diaphragm wall has been made by using three-dimensional finite element method numerical analysis. The calculation result shows that the tensile stress of arc type diaphragm wall is much less than that of plane type diaphragm wall although the compression stress of arc type diaphragm wall is a little larger. Since the tensile strength of concrete is only less than 10 percent of compression strength, tensile stress is the main control factor of diaphragm wall. So the arc type diaphragm wall is probably reasonable especially for concrete face rockfill dam built on a deep alluvium deposit.