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为了证实加载历程对破碎煤样渗透特性的影响,利用一套由齿轮泵、换向阀、溢流阀和渗透仪等组成的渗透回路,在CMT5305型电子万能试验机试验系统上测试了配径碎煤在两种不同试验方案下的渗透特性,得到了两种方案配径碎煤的渗流速度、渗透率、非Darcy流因子与孔隙度的关系。研究表明:①第1种试验方案的渗流速度和渗透率与孔隙度的关系用幂函数拟合,第2种试验方案的渗流速度和渗透率与孔隙度的关系可用指数函数拟合。②孔隙度较大时,渗透率和非Darcy流因子与加载历程有关;孔隙度较小时,渗透率和非Darcy流因子趋于稳定,与加载历程无关。③随着孔隙度的减小,方案1非Darcy流因子由负变正,配径碎煤的渗透性加强;方案2非Darcy流因子始终为负值,配径碎煤的渗透性减弱。④两种方案的非Darcy流因子与孔隙度均可采用三次多项式拟合,多项式的系数与加载历程有关。
In order to verify the impact of loading process on the permeability characteristics of broken coal samples, a set of penetration circuit consisting of gear pump, reversing valve, pressure relief valve and permeation meter was used to test the diameter distribution of CMT5305 universal testing machine According to the permeability characteristics of crushed coal under two different experimental schemes, the relationship between percolation velocity, permeability, non-Darcy flow factor and porosity of the two kinds of schemes was obtained. The results show that: ① The relationship between seepage velocity and permeability and porosity of the first experimental scheme is fitted by a power function. The relationship between seepage velocity and permeability and porosity of the second experimental scheme can be fitted by exponential function. (2) When the porosity is large, the permeability and non-Darcy flow factors are related to the loading history; when the porosity is small, the permeability and non-Darcy flow factors tend to be stable, which has nothing to do with the loading history. (3) As the porosity decreases, the non-Darcy flow factor in Scheme 1 is negative and positive, and the permeability of the broken coal increases. In Case 2, the non-Darcy flow factor is always negative and the permeability of the broken coal decreases. ④ The non-Darcy flow factors and porosity of the two schemes can be fitted by cubic polynomial. The coefficient of polynomial is related to the loading history.