为研究煤矿区用矸石作为垫底基质进行土壤剖面重构土壤水分再分布过程和剖面热扩散与气体浓度变化特征,以指导工程设计和重构土壤熟化技术应用,在实验室设计了一种煤矿区重构土壤水气热运移模拟装置,通过布设在土柱系统不同深度的温湿度传感器和CO2浓度检测仪,连续监测重构土壤剖面含水量、温度和CO2浓度。结果表明:煤矸石层具有良好的阻水性,阻碍水分的入渗,增加上层土壤的持水能力。但是,煤矸石的持水性差,煤矸石层的含水量低于土壤层10%左右;煤矸石具有更佳的热扩散性,在加热过程中煤矸石层的温度远大于土壤层,在重构土壤中容易形成稳定的温度梯度,尤其在煤矸石层与土壤层之间存在明显的温度差。土壤层的温度受底部加热的影响较小,短期内主要受室温影响,其变化曲线与室温日变化曲线基本一致,最大波动幅度在2.89℃;底部通CO2对土壤层CO2浓度的影响非常小,气体在煤矸石层向土壤层扩散时容易受到土壤层的阻隔,导致气体在土壤层下界面累积;煤矸石层会对邻近土壤层产生较大影响,影响微生物的生存环境,导致微生物的活性下降。当覆土厚度为60cm时,煤矸石层对土壤层的影响较小,随着覆土厚度的增加,煤矸石的影响会逐渐削弱。
In order to characterize water redistribution and gas-heat diffusion of reconstruction soil filled with gangue in coal mining areas,guide engineering design and rebuild soil ripening technology,a simulator was designed in laboratory.Soil water content,temperature and soil CO2 concentration could be constantly measured by laid sensors and detectors in different depth of soil column.The results showed that soil water infiltration process was slowed down and the water-holding capacity of the upper soil was increased because of good water resistance from coal gangue layer.However,the water content of coal gangue layer was significantly lower,approximately 10%,than that of topsoil due to the poor water-holding capacity of gangue.Coal gangue had higher thermal diffusivity,higher temperature than that of topsoil with heating,could form sustainable temperature gradient and temperature difference with topsoil layer in reconstruction soil.The effects of heated from below on topsoil was small,which it was mainly influenced from indoor temperature in the short run.In addition,the temperature changing curve of topsoil is similar with the temperature of laboratory and its biggest fluctuation range was for 2.89℃.The effects of aerating CO2 from column bottom on CO2 concentration of topsoil soil was also very small,because gas transport from coal gangue layers to soil ones would easily be cut off as so to gas accumulated in the soil layer below.The coal gangue could have a negative impact on microbial living environment to adjacent topsoil layers and declined microorganism activities.The effects of coal gangue on topsoil layer were brought down when the cover soilthickness was 60 cm.The influences gradually would be weakened with the thickness increased.