一、前言涵洞是铁路和公路上,小型人工泄水建筑物的基本型式之一。虽然每一座的造价较小,但数量大,就其投资总额而言,为数仍然可观。实际使用的经验表明,涵洞的损毁多半由于在水流作用下涵洞出口附近所形成的冲刷而引起的。因此,正确估计涵洞下游冲刷深度是保证涵洞安全和降低涵洞造价极为重要的问题。涵洞下游冲刷现象是水流、河床泥沙和建筑物三者综合影响的结果,尽管其建筑规模较小,而问题的性质却仍然甚为复杂。目前这方面的理论发展还极不成熟,国外也研究不 I. Introduction Culverts are one of the basic types of small-scale artificial drainage structures on railways and highways. Although the cost of each one is relatively small, it is still large in number and still substantial in terms of its total investment. The actual experience shows that most of the culvert damage is caused by erosion formed near the culvert exit under water flow. Therefore, it is extremely important to properly estimate the scour depth at the downstream of culverts to ensure the safety of culverts and reduce the cost of culverts. Scouring downstream of culverts is the result of a combined effect of water flow, riverbed sediment and buildings, despite the small size of the building and the nature of the problem, which is still quite complex. At present, the theoretical development in this area is still immature, and foreign studies are not