Snow distribution on a building surface is uneven due to the complicated drift movements of snow grains affected by the wind. Therefore, an accurate estimation of the snow distribution on a building’s roof is essential in protecting its structure. The existing wind tunnel tests of snow distribution on roofs do not consider the influences of falling snow, resulting in deviations between the test results and the actual snow distribution. In this study, a wind tunnel test method considering the snow falling process was proposed to simulate the irregular snow distribution on stepped flat roofs during snowfall. Based on the test data, the variation rule of snow distribution on the stepped flat roof with different test methods and conditions is summarized. (1) The results of the conventional snow erosion test, which neglected the influences of falling snow, deviated from the existing measurement results. (2) The test results of the proposed method with varying wind speeds and grain sizes met the double-linear or triple-linear rule, which conformed to the measurement results. (3) The initial snow significantly influenced the snow distribution on the front of the lower roof on windward side but only slightly affected the snow distribution on the other locations. The research conclusions could provide significant contributions to the actual engineering design.

由于受风影响的雪粒的复杂漂移运动，建筑表面的雪分布不均匀。因此，准确估计建筑物屋顶上的积雪对保护建筑物的结构至关重要。现有的屋顶雪分布风洞测试没有考虑降雪的影响，导致测试结果与实际雪分布之间存在偏差。在这项研究中，提出了一种考虑降雪过程的风洞测试方法，以模拟降雪期间阶梯状平屋顶上不规则的积雪。根据试验数据，总结了不同试验方法和条件下阶梯平屋顶积雪的变化规律。（1）常规雪蚀测试的结果，忽略了落雪的影响，与现有的测量结果有所不同。（2）所提方法在不同风速和粒度下的测试结果均符合双线性或三线性法则，与测量结果吻合。（3）最初的降雪显着影响了迎风侧下屋顶前部的降雪分布，而对其他位置的降雪分布影响很小。研究结论可为实际工程设计提供重要的贡献。（3）最初的降雪显着影响了迎风侧下屋顶前部的降雪分布，而对其他位置的降雪分布影响很小。研究结论可为实际工程设计提供重要的贡献。（3）最初的降雪显着影响了迎风侧下屋顶前部的降雪分布，而对其他位置的降雪分布影响很小。研究结论可为实际工程设计提供重要的贡献。