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| EXPERIMENTAL STUDY OF VENTILATION PROPERTY AND PARAMETERS OF CUBIC ARRANGED CEMENT BALLS |
| TONG Gangqiang，LI Dongqing，ZHANG Mingyi |
(State Key Laboratory of Frozen Soil Engineering，Cold and Arid Regions Environmental and Engineering Research Institute，
Chinese Academy of Sciences，Lanzhou，Gansu 730000，China) |
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Abstract The block stones are widely used in Qinghai—Tibet railway construction due to the characteristics of good ventilation and heat transfer ability. It plays a positive effect on cooling permafrost. The air flow law inside the block stone layer has become a hot issue. But the particle size and shape of block stones are all irregular，and the packing methods are also random. Therefore，if directly conducting the ventilation experiment with block stone layer，the results obtained are accidentally and uncertainly. In order to avoid all above disadvantages，the permeability and inertial resistance coefficient of layer of cubic arranged cement ball with different diameters are studied by using wind tunnel tests. The diameters of balls are 0.15，0.20，0.25 and 0.30 m，respectively，and the porosities of cubic arranged cement balls were all 0.476. Results of the wind tunnel tests show that the internal pressure gradient of the cement ball layer has a good nonlinear quadratic curve relationship with the seepage velocity. The permeability and the inertial resistance coefficient are related to the diameter of cement balls. With the increase in the diameter of cement balls，the permeability increases and the inertial resistance coefficient decreases.
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Received: 08 February 2010
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2011, Vol. 30 
