破碎矸石分级加载蠕变过程中的渗流试验研究

An seepage experimental study on broken gangue under step loading during creep process

为研究破碎矸石变形后的渗流规律,利用渗透仪、液压泵等组成的渗流系统,在DDL600电子万能试验机上采用分级加载方式,对5种不同粒径破碎矸石进行了蠕变过程中的渗流试验,得到了各级应力水平下岩样的渗透参数,及其Kelvin-Volgt蠕变模型中的各特征参数E0,E1,η1,并对其变化规律进行了分析。结果表明:1)不同粒径岩样随着应力水平的变化,其孔隙度大小差异逐渐减小,同一应力水平下,颗粒间的相互调整随时间推移逐渐停止;2)破碎岩样的蠕变参数E0,E1,η1均随应力水平的提高而增大,小粒径矸石的比面较大,在压缩过程中与其他粒径岩样相比其轴向变形小、蠕变参数E0大,大粒径矸石颗粒间的充填效果明显且其变形大,孔隙连通性减弱,渗流时黏滞阻力大;3)随着孔隙度减小,岩样的渗透率与非Darcy流β因子的绝对值两者近似呈反比关系。破碎矸石密实度越大非Darcy流特性越显著,当颗粒细化程度较大时,破碎矸石渗流过程中易发生渗流失稳。

The permeability test of crushed coal gangues during creep process is performed after these crushed coal gangues which vary in five different diameter sizes, such crushed coal gangues are loaded in different grades in DDL600 electronic universal testing machine by using a set of seepage system consisted of permeability Tester and hydraulic pump, etc. Then, the permeability parameters of coal gangue samples under different levels of the stress and various characteristic parameters of E0, El, 1/1 in Kelvin-Volgt creep model are obtained. The variations of these parameters are analyzed. The results are as follows： 1） the porosity difference of the coal gangue samples in different sizes decreases gradually with the change in stress levels; under the same stress level, the mutual adjustment between particles gradually stop over time; 2） the creep parameters of crushed gangue samples, E0, El, and ql increase with the increase of stress levels; because gangues with smaller-size surface have larger specific surfac-es, the axial deformation of these gangues is smaller and creep parameter E0 ~s larger m me compression process comparing to the samples with other particle sizes. The larger-size particles have good filling effects. Samples＇ large deformation could generate their weak connectivity and the viscous resistance of seepage is higher; 3） as the porosity decreases, an approximately inverse relationship between the abso- lute value of gangue permeability and that of the factor of non Darcy flow can be found; the bigger the compactness of crushed gangue samples is, the more notable non-Darcy property is. The seepage insta- bility of broken crushed coal gangues occurs when the breakage of refinement is serious.