基于压汞试验的煤可压缩性研究及压缩量校正

Study on coal compressibility and correction of compression amount based on compressibility of mercury injection test

为了提高压汞试验结果的可靠性和适用性,以准确表征煤的孔隙结构,根据弹性力学基本原理,结合分形分维的思想,在10~206 MPa压力范围内,基于压汞数据计算了煤基质的压缩系数,并结合液氮吸附数据对压汞试验结果进行校正。得到煤样的基质压缩系数在0.671×10-10~1.23×10-10m2/N,校正后总孔容与校正前相差48.62%~54.89%,孔隙结构与液氮吸附试验结果更加接近。压力大于206 MPa时煤的孔隙结构变化十分复杂,对应孔径小于6 nm的测试结果不宜采用。压力在10~206 MPa时,累计压缩量与填充量呈幂函数关系。

In order to improve the reliability and suitability of the mercury injection test results,with accurate explanation of the pore struc-ture of the coal,according to the basic principle of the elastic mechanics,in combination with the idea of the fractal dimension,within thepressure scope of 10 ~ 206 MPa,the compressed coefficient of the coal was calculated based on the mercury injection data,in combinationwith the liquid nitrogen adsorption data,correction was conducted on the mercury injection test results. The base compressed coefficient ofthe coal sample was 0. 671×10-10~ 1. 23×10-10m2/ N,the difference between the total pore volume after and before the correction was48. 62% ~ 54. 89%. The pore structure and liquid nitrogen adsorption test results were more close to each other. When the pressure was o-ver 206 MPa,coal pore structure would be varied complicated. The test results of the related pore diameter less than 6 nm would not be forapplication. When the pressure was in 10 ~ 206 MPa,the accumulated compression amount and the backfill value were in a power functionrelationship.