防止高拱坝坝踵开裂和屈服的工程措施研究

对防止高拱坝坝踵开裂和屈服的两种常用工程措施周边缝和底缝进行研究．研究中坝体混凝土、缝和坝基材料采用不同的非线性材料模型．结合292m高的小湾拱坝对设缝前后的坝体位移场、应力场、开裂区和屈服区进行分析研究,重点讨论设缝对坝体屈服和开裂的影响．对小湾拱坝的研究结果表明：(a)未设缝时,在坝基附近的垫座内出现较大范围的开裂和屈服;设置周边缝时,垫座内的开裂和屈服明显减少;设置底缝时,坝踵附近的开裂和屈服明显减少,但在设缝两侧,尤其是两侧缝端附近,垫座内的屈服现象比无缝情况时更严重．(b)小湾拱坝设周边缝的效果要优于设底缝,设缝范围可限制在缝面开裂的范围内．

Engineering measures for prevention of cracking and yielding of high arch dams

The feasibility of two usual engineering measures of setting peripheral joints and base joints to prevent cracking and yielding of high arch dams is studied for arch dam design. Different nonlinear material models of dam bodies, joints, and dam foundations are adopted in the calculation. With the Xiaowan arch dam, 292m in height, as an example, the displacement field, stress field, and cracked and yield region of the dam in the absence and presence of joints in the dam body are compared, with emphasis placed on the influences of joints on the cracking and yielding of the dam body. The results show that without joints, large areas of cracking and yielding occur in the cushions near the dam foundation, and that peripheral joints and base joints obviously reduce the cracking and yielding in cushions and near the dam heel, while on two sides of base joints, especially at the ends of the joints, the yielding in the cushion is more serious than that without joints. It is also concluded that the effect of peripheral joints is superior to that of base joints, and that joint setting should be limited to the regions where joint face cracking occurs.