摘要
对小湾工程高水头、大流量坝身泄洪条件下，护坡不护底水垫塘进行了系统地试验研究．在按基岩微弱风化界面铺设动床的情况下，水垫塘基岩冲刷试验表明，坝身泄洪的水垫塘控制工况是表、中孔联合泄洪的工况；在各种泄洪工况下，当基岩抗冲流速为 10～12 m／s 时，校核洪水下基岩冲刷平衡深度小于 15 m．改变二道坝高度的冲刷试验表明，二道坝高度能减少基岩冲刷平衡深度，但高度增加值和基岩冲刷平衡深度的减少值并不相等，适宜的二道坝高程为 1 004．00～1 008．00 m．改变水垫塘两岸边坡的冲刷试验表明，水垫塘底宽对基岩冲刷平衡深度的影响较大，坝身表、中孔单泄时，水垫塘底宽应大于挑流水舌横向重叠的宽度；表、中孔联合泄洪时，水垫塘底宽应大于水舌入水总宽度，否则基岩冲刷平衡深度急剧加深． 根据试验研究和分析提出了一种护坡不护底水垫塘的优化体型——勺型水垫塘，给出了体型尺寸和相应的试验结果．试验表明，小湾水电站水垫塘在现有泄洪布置和基岩抗冲流速 10～12 m／s 的前提下，采用护坡不护底的型式是可行的，如能实现，则将取得显著的经济效益．
： Systematic research on the cushion pool with lining slope but no bottom protection under the circumstance of high arch dam with large discharge has been carried out． Firstly，as river bed are comparatively wide，model tests on rocky scour in the cushion pool show that the control scour depth of cushion pool happen on the joint operations on surface outlets and middle outlets as well． Among the various discharging conditions，rocky scour depth as flood occurs only once in ten-thousand years is less than 15 m on condition that anti-erosion velocity of rock in the cushion pool reaches the range of from 10 to 12 m／s． Secondly，research through changing the depth of secondary arch dam indicates that is the decease of the scour depth is unequal to its increment even though the elevation is able to decrease the scour． The best elevation changes from 1 004 m to 1 008 m after close testing and reasoning． Scour tests on changing the slopes and the base width of cushion pool obtain that the base width gives great effect on the scour depth． In the joint operation，the width should be little greater than the transverse width of water jets as they enter water，or rocky scour may sharply deepen． Lastly，an optimized scoop shaped of cushion pool in the form of lining slope but no bottom protection is proposed． Experiment show that it is feasible for Xiaowan cushion pool to adopt the form of the lining shopes but no bottom protection on condition that anti-erosion of rock can reach between 10 and 12 m／s，which can arrive a considerable economic benefit if it is applied to put into practice．
出处
《水利水电技术》
CSCD
北大核心
2001年第5期52-56,共5页
Water Resources and Hydropower Engineering
基金
"九五"重点科技攻关项目!(96-221-05-01-02)
关键词
水垫塘
基岩
高拱坝
护坡不护底
小湾工程
： cushion pool；rock；scour depth；high arch dam；large discharge with lining slope but no bottom protection；Xiaowan Project
