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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.
Block stone ventilation is the main measure to protect permafrost during the construction of Qinghai-Tibet Railway. Accurately describing the air flow in block stone is the primary problem in the numerical analysis of cooling effect of block gravel roadbed.By means of wind tunnel test, The relationship between seepage velocity and pressure gradient, the average particle size of rock block in experiment is 12.5cm and the porosity is 0.487, the data of wind speed and pressure difference are measured under different fan speed.The results show that the air seepage velocity With the increase of pressure gradient, there is a nonlinear relationship between pressure gradient and seepage velocity.Based on Forchheimer equation, the permeability and inertia resistance coefficient of block rock are obtained by the experimental data.These results can be used for various rock and stone structures The basis of numerical analysis of subgrade cooling effect is provided.