煤矸石山风化堆积物水分动态研究

Research on Water Dynamics of Weathered Coal Gangue Dumps

以山西省阳泉市280煤矸石山为研究对象,通过对煤矸石物理性质、水分入渗特性和水分含量的分析,初步研究了煤矸石山风化堆积物水分的动态特征。研究结果表明,煤矸石质地较差,砾石和块石平均含量达86.07%。煤矸石山孔隙组成以非毛管孔隙为主,其剖面4个深度(0—15cm,15—30cm,30—45cm,45—60cm)的毛管孔隙度平均值分别为1.40%,1.36%,1.32%和1.17%,导致土壤持水量常年维持在较低水平,0—60cm的平均土壤持水量为19.7t/hm2。Kostiakov入渗模型能较好地反映研究地区煤矸石风化物的入渗过程,且在入渗过程中煤矸石风化物一直保持着较高的渗透速率。煤矸石风化堆积物水分季节性变化主要受降水量及其季节分配的影响,随着季节性降水量的增加,矸石风化物水分平均含量也相应升高。煤矸石山的储水量与降水量之间,表现出较好的一元线性正相关关系。在降雨量较少,或是降雨次数多,雨强较大的情况下,裸露煤矸石地的储水量往往大于覆土煤矸石地的储水量。一般情况下,煤矸石山30—40cm深处有明显的干层,使得煤矸石山下层在旱季保持有较多的水分。

Water dynamics of the 280 coal gangue dumps in Yangquan City, Shanxi Province was preliminarily studied by the analyses of physical properties, water infiltration characteristics, and water content of the weathered gangue. Results showed that coal gangue texture was poor and the average content of gravel and boulder was as high as 86.07%. The coal gangue dumps were dominated by non-capillary pore and the average values of capillary pore at the four depths （15, 30, 45, and 60 cm） in the profile were 1.40%, 1.36%, 1.32%, and 1. 17M, respectively. This caused soil water-holding capacity maintaining at a low-level throughout the year and the average water-holding capacity at 60 cm depth was 19.7 t/hm^2. Kostiakov infiltration model can well describe the infiltration process of weathered gangue. During the infiltration process, weathered gangue had higher infiltration rate. The seasonal change in water content of weathered gangue was mainly influenced by the amount of rainfall and its distribution. With the increasing seasonal rainfall, the average water content of weathered gangue rose correspondingly. Water storage of gangue dump was linearly related with the amount of rainfall. When the amount of rainfall was low, or rainfall event was highly frequent, water storage of exposed gangue was more than that of the gangue dump covered with soil. Generally speaking, there was a dry layer between 30 and 40 cm in gangue dump, which made the lower layers of gangue dump keeping more moisture in dry season.