臺階式溢流壩消力池壓強特性試驗研究

趙相航+解宏偉+顧聲龍+賀巨龍+郭馨

摘要：為研究臺階式溢流壩不設反弧段連接時消力池底板壓強特性，結合某水庫實際工程，采用物理模型試驗方法，對臺階式溢流壩消力池底板時均壓強、脈動壓強強度和峰值等壓強特性進行了研究。結果表明，消力池底板時均壓強均為正值；在滑行水流和過渡水流時，時均壓強在水流沖擊區出現一個較大值，最大為0.926 kPa，下游反彈區形成極小值；在跌落水流時，時均壓強沿程變化較小，且隨流量的增加而增大；脈動壓強強度和峰值沿程變化規律基本一致，總體上隨流量的增加而增大，最大值出現在水流沖擊區，脈動壓強最大為1.198 kPa，隨后沿下游方向逐漸減小，并趨于穩定；臺階尺寸對消力池底板時均壓強和脈動壓強影響不大；消力池內脈動優勢頻率為0.01～4 Hz，屬低頻振動，不會危害泄水建筑物的安全。研究成果可為臺階式溢流壩消力池的優化設計提供參考。

關鍵詞：消力池；臺階式溢流壩；時均壓強；脈動壓強；頻率

中圖分類號：TV135.2 文獻標識碼：A 文章編號：1672-1683（2017）03-0171-06

Abstract：To study the pressure characteristics in the stilling basin of a stepped spillway without anti-arc，we chose a reservoir and used the physical model test method to study the pressure characteristics including time-average pressure，fluctuating pressure intensity，and peak pressure pulsation in the stilling basin of a stepped spillway.The results showed that all the time-average pressure was positive in the stilling basin.When the flow regime was skimming flow and transition flow，the time-average pressure became large in the flow impact area，reaching a maximum of 0.926 kPa；it reached the minimum in the downstream rebound zone.The time-average pressure varied slightly when the flow regime was nappe flow，and increased with the increase of flow.The variation patterns of the fluctuating pressure intensity and peak pressure were basically consistent.They both increased with the flow on the whole.The maximum value appeared in the flow impact zone.The maximum fluctuating pressure was 1.198 kPa.It then decreased gradually in the downstream direction until it became stable.The step size hardly affected the time-average pressure and fluctuating pressure on the floor of the stilling basin.The dominant frequencies of fluctuations in the stilling basin were 0.01～4 Hz，which belonged to the low-frequency vibration and will not endanger the safety of drainage buildings.

Key words：stilling basin；stepped spillway；time-average pressure；fluctuating pressure；frequency

臺階式溢洪道是結合碾壓混凝土技術提出的一種新型溢洪道消能工，廣泛應用于各類中小型工程，它具有施工工期短、消能效果好、水流摻氣濃度大、工程投資低等優點，受到廣大研究人員的重視，并進行了大量的研究[1-14]，但其研究成果主要集中在臺階段，對臺階式溢流壩壩后消力池水力特性研究的較少。Yasuda等[15]通過模型試驗對不同坡度溢洪道消力池內水躍的摻氣濃度分布和紊動強度變化進行了分析；……