摘要
为了防止矸石山水土流失,促进煤矿废弃地植被恢复,对自然降水条件下煤矸石坡面含水量及径流变化进行观测,研究降水量及风化年限对煤矸石坡面各层含水量及产流量的影响。结果表明：1）在小雨（〈10 mm/d）条件下,煤矸石坡地表、地下径流量接近;在中雨（≥10 mm/d,〈25 mm/d）及大雨（≥25 mm/d）条件下,降雨主要以地下径流的形式流失。在小雨情况下,煤矸石坡产生的地表径流、地下径流量均较少;中雨的发生频率和累计降水量最高,累计产生的地表径流量最高;大雨发生频率最低,累计产生的地下径流量和总径流量最高。2）地表径流量与降水量显著正相关,地下径流量与最大降雨强度、平均降雨强度显著正相关。3）由于风化程度增加,与2013年相比,2014年次小雨产生的地表径流、地下径流和总径流分别降低50%、100%、80%,次中雨产生的地表径流、地下径流和总径流分别降低88%、82%、97%。4）煤矸石具有一定的蓄水能力,20～30 cm含水量最高。随着风化程度增加,10～30 cm含水量增加。尽管10 cm风化程度高,但是由于表层蒸发,含水量较低。5）由于煤矸石颗粒粗大、渗透性强,在小雨、中雨、大雨条件下,矸石坡产生的地表径流量均小于土坡,分别为土坡的4%、26%、19%。
[Background] Gangue is an undesirable material generated during shaft building,coal mining,and coal washing. Gangue is dug out from underground and piled up on the surface,which is called gangue dump. Because of the harsh site conditions of gangue dump,the recolonization of plants is very difficult. [Methods] In order to prevent erosion and facilitate revegetation in coal gangue dump,the volumetric water content and runoff of a coal gangue slope under natural precipitation were monitored for 2 years. The coal gangue was evenly spread on the 38° runoff plot and formed a slope with a depth of70 cm. The base of the slope was impermeable,and the surface and groundwater runoffs were collected separately 1 day after each rainfall event. The effects of natural precipitation and weathering on volumetric water content and runoff were tested. [Results] 1） On average,during each light rainfall event（ 〈10 mm / d）,0. 014 mm surface runoff and 0. 019 mm groundwater runoff were produced,i. e.,the amounts of surface and groundwater runoffs were similar, and a small amount of surface and groundwater runoffs were generated on coal gangue slope. Moderate rains happened at the highest frequency and accounted for most surface runoff. In each moderate rainfall event（ 10- 25 mm / d）,0. 117 mm surface runoff and 0. 962 mm groundwater runoff were generated, meaning that more precipitation was discharged as groundwater runoff. While heavy rains occurred at the lowest frequency and accounted for most groundwater and total runoff,during each heavy rainfall event（ 〉25 mm / d）,0. 254 mm surface runoff and 4. 253 mm groundwater runoff were generated. 2） The amount of surface runoff was positively correlated to precipitation,and the amount of groundwater runoff was positively correlated to maximum precipitation intensity and mean precipitation intensity. However,the correlation between precipitation intensity and surface runoff was not significant,which probably resulted from the fact that the infiltration rate of coal gangue was generally higher than the precipitation intensity. The correlation between precipitation and groundwater runoff was also not significant. 3） In 2014,due to the increase of weathering,the amounts of surface runoff,groundwater runoff and total runoff during each light rainfall event decreased by 50%,100% and 80% respectively, compared to 2013. During moderate rainfalls,they decreased by 88%,82% and 97% respectively. 4） Coal gangue held a certain amount of water,and the volumetric water content in 20- 30 cm coal gangue was the most. Volumetric water content in 10- 30 cm ones increased as gangue weathered despite less water input from precipitation in 2014, indicating water holding capacity increased. Even though gangue in 10 cm was highly weathered,the water content was low because of high evaporation rate. 5） Because of its coarse texture and high infiltration capacity,the surface runoffs on the coal gangue slope during light,moderate and heavy rainfall events were 4%,26% and 19% of those on the soil slope respectively. [Conclusion]This research will guide the practice of soil and watter conservation in gangue dump.
出处
《中国水土保持科学》
CSCD
北大核心
2016年第4期60-67,共8页
Science of Soil and Water Conservation
基金
国家林业公益性行业科研专项"四川地震灾区灾后植被恢复及可持续发展关键技术研究与示范"(201104109)
关键词
煤矸石
径流量
降水
含水量
风化
coal gangue
runoff
precipitation
volumetric water content
weathering
