泥石流作用下砌体房屋破坏机理与结构优化

山洪泥石流是我国山区导致房屋损毁和人员伤亡的主要灾种。由于地形条件限制，我国山区房屋大量分布在较为平坦的泥石流堆积扇上，成为泥石流爆发时的危害对象。针对砌体结构这一山区房屋的主要结构类型，提高其在泥石流作用下的稳定性，是一个亟待解决的问题。本文分析了泥石流对房屋作用特点，提出砌体结构房屋中关键承重结构的破坏模式。以墙体弯曲应力破坏准则为基础，结合泥石流冲击力与流速流深的定量关系，建立了基于泥石流流速流深的砌体墙结构破坏模型，找出了不同砌体墙的破坏临界条件。从结果可以看出，传统砌体结构抵抗泥石流冲击能力极低。以240mm厚的墙体为例，当泥石流流速为4m/s时，一旦泥石流深度超过0.4m，受到正面冲击的墙体将会发生破坏。在考虑砌体墙结构特性的基础上，本文提出了泥石流危险区砌体房屋优化方案。进而，通过七盘沟泥石流灾害调查中的房屋破坏实例，验证了方案的可行性，为提高受泥石流作用影响的房屋的抗灾能力提供新思路。

Failure mechanism and structure optimization of masonry building due to debris flow impact

Flood and debris flow are the main contributor of mountain hazards in China. Along these years, due to the space limitation, buildings, which are the main element at risk, are mostly located at debris flow alluvial fan. This have led to buildings extreme vulnerable when mountain hazards occur. Based on the characteristic of debris flow impact and structural behavior of masonry structure, failure mechanism of the masonry brick wall is identified. The bending stress failure criteria of brick wall is calculated based on the debris flow velocity and depth. Failure curve of brick walls are constructed to assess wall failure subject to different flow velocity and depth. Base on the result, two structure optimization plan are proposed. The brick wall failure model and optimization plan is verified by a masonry building at Qi Pan Valley after a devastating debris flow event on 2013. The advantages and limitations of two structure optimization plan were discuss.