典型山体地貌下受山坡与建筑间距影响的低矮房屋风荷载风洞试验研究

Wind tunnel test on low-rise buildings influenced by spacing between hillside and building in typical mountain terrain

通过风洞试验对3种典型山体地貌下低矮房屋的风压分布规律进行研究,并与无周边干扰的低矮房屋风压分布进行对比,讨论了低矮房屋在0°风向角下,随山坡与建筑间距变化时,平均风压系数、体型系数的变化规律,进而分析了低矮房屋在0°~90°风向角下平均风压系数的变化趋势。结果表明：当房屋后方有山坡时,建筑迎风面、背风面、侧面和屋面所受风压均为正压;随着房屋与山坡间距的增大,迎风面所受正压总体先减小后增大,侧面与背风面所受正压总体减小,屋面边缘处开始出现负压且绝对值逐渐增大;接近无周边干扰时,建筑表面风压变化显著,其迎风面正压继续增大,而背风面、侧面和屋面所受风压变为负压。从体型系数上看,背风面受山体的影响最为明显,而迎风面受山体的影响较小。迎风屋檐、左侧面左边缘处、右侧面右边缘处及迎风面中线、背风屋面中线、背风面中线处可能产生相对其他部位更大的风压,在设计时应考虑这些较高的局部风压而引入局部风压系数,以避免房屋的局部破坏。在受山体环境影响时,不同风向角下的平均风压系数与无周边影响时相差较大,当风向角为0°且无周边干扰时,迎风屋面的平均风压系数出现负压极值-1.15,在进行低矮房屋设计时,应考虑受山体环境影响时低矮房屋的最不利风向角。

The wind pressure distribution on scaled model of low-rise building in three typical mountain terrain of coastal areas was studied with pressure measurement wind tunnel tests. At the same time, they were compared with the wind pressure distribution of low-rise building in isolated condition. The study mainly focused on the variation of average pressure coefficient and shape coefficient with the change of spacing between the hillside and building under wind attack of 0° , then the trends of average wind pressure coefficients of low-rise building under wind attack of 0- 90° were analyzed. It is found that when the mountain is behind low-rise building, the values of wind pressure on windward, leeward, flank and roof are positive. As the distance increases, the positive value of wind pressure on windward decreases and then increases gradually. The positive value of wind pressure on flank and leeward decreases generally and the pressure on leeward, flank and roof changes to negative, whose absolute value increases generally. In isolated condition, the pressure changes obviously, the pressure on windward continues to increase and the pressure on leeward, flank and roof changes to negative. From the aspects of shape coefficients, the influence on leeward affected by hillside is the most obvious, and the influence on windward is small. Some part, such as windward cave, left edge of left side, right edge of fight side, midline of windward, leeward, should be paid more attention in the design for their absolute values of the mean pressure coefficients. With respect to relatively high partial wind pressure, partial wind pressure coefficient can be introduced in design to avoid partial damage to low-rise building. At different wind angle, the mean wind pressure under the conditions of being affected by slope is significantly different from that under isolated condition. When the wind angle is 0°, the negative peak value （ - 1.15 ） of mean wind pressure coefficient is observed on windward cave under the isolated condition. The wind load producing the most negative effect shall be taken into account in the calculation when designing low-rise building.