宽尾墩+台阶式溢洪道的消能形式已被许多工程所应用,但从近年工程运行情况看,个别工程出现台阶面破坏现象。根据工程模型试验资料,结合同类工程原型观测资料,对有可能在宽尾墩水舌作用下,影响台阶面出现破坏的时均压强、近底流速、掺气浓度等水力学参数分别进行了测试分析;同时,依据台阶面脉动压强和时均压强试验测试数据,采用材料力学方法,对台阶面混凝土分层后的受力情况也进行了分析。结果表明若台阶面碾压混凝土出现分层与表面止水破坏,则脉动压强就会通过表面缝隙与层面间隙作用于混凝土,混凝土也可能因此出现最大正应力,而当最大正应力超过混凝土的抗拉强度,台阶面混凝土就可能出现破坏。

Joint energy dissipation of stepped spillway and flaring gate pier was used in many projects, but the stepped surface damage was recently found in several projects. According to the model test and prototype measurement, the hydraulic parameters such as time average pressure, flow velocity near bottom and aeration concentration possibly affecting the damages of stepped surface under the action of nappe of flaring gate pier were analyzed. In the same time, the method of mechanics of materials was used to conduct force analysis of stepped concrete layers in association with fluctuating pressure and testing data of time average pressure. Results show that, under the conditions of stratifying of roller compacted concrete(RCC) and the damage of surface sealant , fluctuating pressure will act on concrete through surface fissures or interlayer fissures . Thus the maximum tensile stress will possibly occur and when it exceeds tensile strength of concrete, stepped concrete surface is possible to be harmed.