Compaction Strength Affected to Air Barrier Property of Covering Materials on Coal Rejects Dumping Pile

In order to study the related rolling compaction method and parameters in the covering layer building process of the coal rejects dumping pile, in combin ation with the site conditions of the coal rejects dumping pile contral in Yangyquan No. 3 Mine, based on the powder soil and fly ash applied as the test material, an ind oor simulation was applied to measure and test the air barrier property of the samples under the different compaction strengths. The paper analyzed the compaction str ength affected to the fire resistance effect of the material and discussed the rolling strength in the comprehensive control of the spontaneous combusted coal rejects du mping pile affected to the barrier function effect of the covering layer. An optimal rolling strength was provided. The results showed that the compaction strength would affect the air seepage velocity of the material and there was a negative index function relationship between the compaction strength and the material. With the compacti on strength increased, the air barrier property of the material would be steadily increased. When the compaction power per unit volume was increased from 50 kJ 1 m3to 300 kJ 1 m3, the average permeability would be reduced from 1.22 x10-13m2to2. 17 x 10- 15m2. Under the different pressure difference, there was a characteristic poin t in the curve of the permeability velocity varied with the compaction function. When the pressure difference was 2 ~ 10 kPa, the most effective compaction power of the unit volume was 100 ~ 150 kJ 1 m3.