低矮建筑屋盖风雪流作用场地实测与数值模拟

发布时间：2018-01-12 16:25

本文关键词：低矮建筑屋盖风雪流作用场地实测与数值模拟　出处：《振动与冲击》2017年22期 　论文类型：期刊论文

【摘要】：为了研究风雪流对低矮建筑屋盖的作用,制作了6组缩尺模型,在常遇雪天气候下,开展了屋盖积雪特性场地实测与模化分析,考虑了典型的阶梯型屋面以及平屋面、双坡屋面、女儿墙等因素的影响,提出了典型低矮建筑屋盖积雪荷载模化模型。研究表明:阶梯型屋面的积雪分布与已有的场地实测及风洞试验结果相似;平屋面雪荷载沿来流方向呈倒U型分布,可模化为均匀分布,但随着风速变化,积雪漂移使积雪形态可能向倒V型演化,建议考虑其线性非均匀分布对结构的不利影响;风速较低时,双坡屋面的积雪漂移量较少,对迎风侧屋盖更不利,国内外规范均侧重考虑了积雪漂移对背风侧的影响,建议考虑弱风条件下积雪漂移对迎风侧的不利影响;女儿墙的存在使屋面积雪量有较大的增加,屋盖前缘和后缘区域的漂移长度差异较大。结合风洞试验与场地实测,考虑雪粒子与风场的双向耦合、雪粒碰撞、黏结,探索性地对阶梯型屋面的积雪分布进行了二维数值模拟,论证了DEM-CFD风雪流模拟方法的可行性。
[Abstract]:In order to study the effect of snow flow on the roof of low buildings, six groups of scale models were made, and the site measurement and modeling analysis of snow cover characteristics were carried out under the usual snowy weather. The effects of typical stepped roof, flat roof, double slope roof and parapet are considered. A model of snow cover load modeling for typical low rise buildings is proposed. The results show that the snow cover distribution of stepped roof is similar to that of existing sites and wind tunnel tests. The snow load on the flat roof presents an inverted U shape distribution along the direction of the flow, which can be modeled as uniform distribution, but with the change of wind speed, the snow drift may lead to the evolution of the snow cover shape to the inverted V type. It is suggested that the adverse effects of its linear nonuniform distribution on the structure be considered. When the wind speed is low, the snow drift of double-slope roof is less, which is more disadvantageous to upwind side roof, and the influence of snow drift on leeward side is taken into account in domestic and foreign codes. It is suggested that the adverse effects of snow drift on the upwind side be considered under the condition of weak wind. Due to the existence of parapet, the amount of snow on the roof increases greatly, and the drift length of the front and rear edge of the roof varies greatly. Combined with the wind tunnel test and the site measurement, considering the two-way coupling of snow particles and wind field, the snow particle collision is considered. Two dimensional numerical simulation of snow cover distribution of stepped roof is carried out, and the feasibility of DEM-CFD snow flow simulation method is demonstrated.
【作者单位】：西南交通大学土木工程学院;西南交通大学高速铁路线路工程教育部重点实验室;
【基金】：国家自然科学基金项目(51378428) 西南交通大学青年科技创新项目(SWJTU12CX069)
【分类号】：TU312.1
【正文快照】： 随着全球极端气候的频繁出现,因风雪流作用导致房屋结构垮塌的报道常见诸于媒体,既有事故调查表明:雪荷载过大、局部不均匀堆载及风雪耦合作用是导致灾害发生的主要原因[1]。特别是近年来被广泛使用的大跨度建筑钢结构,因其竖向刚度较弱、围护体系轻薄,对竖向荷载的非均匀分布

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