不同类型拦挡坝拦蓄特征试验研究

由于陇南泥石流灾害破坏性强，拦挡坝拦蓄性能不清晰，因此通过无泄水涵洞拦挡坝、有泄水涵洞拦挡坝及不设拦挡坝的对比试验，模拟了泥石流发生后坝体的拦蓄性能和流体特征。通过试验获取了坝后淤积物体积函数模型，并讨论了拦挡坝振动加速度、冲击力和槽底不同位置处含水率变化情况。结果表明：加拦挡坝减弱了泥石流对试验槽壁和槽底的陶蚀振动，无泄水涵洞拦挡坝因坝体封闭，短期内淤积了大量泥石流，导致其对试验槽的振动小、流通间隙短，对坝前的冲击力整体减弱，水石分离变差；有泄水涵洞拦挡坝因涵洞的汇流、疏通作用，导致其对试验槽振动较大、流通间隙较长，其坝后淤积量为无泄水涵洞拦挡坝的1/3,且因涵洞的分流作用，使其对坝前冲击力整体增大。分析含水率数据得出，淤积区和未淤积区的分界处，其含水率较其他部位低。基于上述单拦挡坝的性质，再加之陇南多数拦挡坝已淤满，因此，构绘了多坡度新型拦挡坝，其主要特征为，在坝体的背面设置了不同坡度的冲击面，其很好地减弱了泥石流的冲击力，多坡度面分别为跌水区、缓坡区、大角区。

Experimental Study on the Retaining Characteristic to Different Style Retaining Dams

Due to the strong destructiveness of debris flow in Longnan, the retaining performance of the retaining dam is not clear. Therefore, the retaining performance and fluid characteristics of the dam body after the occurrence of debris flow were simulated through the comparative test of the retaining dam without discharge culvert, the retaining dam with discharge culvert and the retaining dam without retaining dam. The volume function model of sediment behind the dam was obtained through experiments, and the vibration acceleration, impact force and water content changes at different positions of the retaining dam were discussed. The results show that the addition of retaining dam weakens the ceramic erosion vibration of debris flow on the wall and bottom of the test groove. Due to the closure of the dam body, the retaining dam without discharge culvert has deposited a large amount of debris flow in a short time, resulting in small vibration to the test groove, short flow gap, overall weakening of the impact force in front of the dam, and poor separation of water and stone. Due to the confluence and dredging effect of the culvert, the retaining dam with discharge culvert has large vibration to the test groove and long flow gap. The sedimentation behind the dam is 1/3 of that of the retaining dam without discharge culvert, and the impact force in front of the dam is increased as a whole due to the diversion effect of the culvert. The analysis of water content data shows that the water content at the boundary between the silted area and the non silted area is lower than that at other parts. Based on the nature of the above single retaining dam and the fact that most of the retaining dams in Longnan are full of silt, a new multi slope retaining dam was constructed. Its main feature is that the impact surface with different slopes is set on the back of the dam body, which can well weaken the impact of debris flow. The multi slope surfaces are water drop area, gentle slope area and Dajiao area respectively.