兰新铁路百里风区风沙流结构特性研究

Study on Structural Characteristics of Gobi Wind Sand Flow in 100 km Wind Area along Lan-Xin Railway

通过对兰新铁路百里风区戈壁风沙流进行现场观测研究,提出风沙流密度的新概念,解决风沙流研究中如何利用现场定时观测研究风沙流动态变化特点的重大技术难题。根据现场实测资料分析,揭示风沙流密度沿高度变化的特点,不同高度风沙流密度与风速的关系,阐明临界风速的概念,认为风区建(构)筑物所承受的压强为净风压与沙粒冲击压之和。在自然风速超过临界风速情况下,风区建(构)筑物所承受风沙流压强以沙粒与建(构)筑物碰撞压力为主,这与传统设计中以净风压作为风荷载设计完全不同,解决了风区工程设计中遇到的技术难题,避免由于对戈壁风沙流的认识不足而造成的损失,对即将修建的兰新二线提供一定的借鉴和参考,对戈壁地区风沙流科学的完善也具有一定的意义。

Through field survey of wind sand flow movement in the 100 km wind area along the Lan-Xin Railway,a new concept,the density of wind sand flow,is put forward.The relation between the height and density of wind sand flow and the relation between the density of wind sand flow and wind speed at different heights are revealed.The conception of the critical wind speed is exposed.The pressure on the structures in the wind area is considered to be the sum of the pure wind pressure and the sand collision pressure.When the natural wind speed exceeds the critical wind speed,the pressure on the structures in the wind area is considered to be primarily the collision pressure between sand and structures.This is completely different from conventional design where the pure wind pressure is taken as the wind load.The study offers some reference to construction of the second line of the Lan-Xin Railway and to perfection of the Gobi wind sand flow science.