通风块石层非达西效应的试验研究  

Experimental Study of Non-Darcy Effects of Ventilative Crushed-Rock Layer

作　　者：李靖波[1,2] 赵爱国[3] 杨玉贵[1] 董元宏[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000 [2]宜春学院物理科学与工程技术学院,江西宜春336000 [3]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2010年第2期335-340,共6页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金(40730736;40821001);国家高技术研究发展计划(863计划)项目(2008AA11Z103);冻土工程国家重点实验项目(SKLFSE-ZY-03)资助

摘　　要：块石通风路基是青藏铁路建设中保护多年冻土的主要措施,准确地描述空气在块石中的流动是块碎石路基冷却效应数值分析的首要问题.通过风洞试验研究了块石层内部渗流速度和压力梯度的关系,试验中块石的平均粒径为12.5cm,孔隙率为0.487,风速和压力差数据是在不同的风机转速下测得.结果表明:块石层内空气渗流速度随压力梯度增大而增大,压力梯度与渗流速度之间存在非线性关系.基于Forchheimer方程,利用试验数据获得了块石层的渗透率和惯性阻力系数.这些结果可为各种块石结构路基降温效果的数值分析提供理论基础.Crushed-rock embankment is a main cooling measure in permafrost regions along the Qinghai-Tibet Railway. An accurate description of airflow within crushed-rock layer is a key in numerical analysis of the cooling effects of crushed-rock embankment. A wind tunnel experiment is carried out to investigate the relationship between the seepage velocity and the pressure gradient within crushed-rock layer. In the experiment,the mean particle size of the crushed rock is 12.5 cm with a porosity of 0.487. The pressure gradients and the seepage velocities in the crushed-rock layer are measured under different outside wind speeds. The experimental results show that the seepage velocity increases nonlinearly with pressure gradient,and their relationship can be well-expressed by the Forchheimer equation.In addition,the permeability and the inertial drag coefficient of the crushed-rock layer are obtained based on the Forchheimer equation. The study provides a scientific basis for numerical analysis of the cooling effects of crushed-rock embankments with different structures.

关 键 词：块石层 多孔介质 非达西效应 风洞试验 多年冻土路基 

分 类 号：P642.14[天文地球—工程地质学]