浅埋煤层开采经常诱发一系列的生态环境问题，为研究浅埋煤层开采区地面塌陷影响下的土壤水分运移规律并提出相应的调控方法，以西部风沙区浅埋煤矿为研究对象，将采煤塌陷对包气带结构的影响分为3个阶段:开采前，包气带较薄，土壤颗粒相对均一;开采中，水位明显下降，包气带厚度急剧增加，裂缝发育且土壤颗粒均一性变差;开采后，风沙区大多数地裂缝自然弥合，但土壤中的黏性颗粒减少，砂性颗粒增多，出现明显的粗化现象。以此为物理背景，构建了不同裂缝宽度二维土壤水分运移模型，结果显示:无裂缝时湿润锋平行向下运移，同一深度的土壤含水率基本相同，裂缝存在时湿润锋沿着裂缝快速运移，优势渗流现象明显;土壤含水率随裂缝宽度的增加呈减小趋势，含水率影响范围随裂缝宽度增加呈增大趋势;当包气带厚度大于极限蒸发深度(300 cm)时，入渗补给量和包气带厚度基本无关，仅会延长土壤水分通过包气带运移到潜水面的时间，对地下水的潜在补给量影响较小。现场调查了塌陷区和非塌陷区沙蒿的生长状况:受塌陷区土壤水分匮缺(吸水水源不足，含水率小于0.1 cm3/cm3)和塌陷诱发的植被根系密度降低(吸水通道降低，根系总干质量减小21.7%)2种因素影响，塌陷区沙蒿平均地上生物量相对非塌陷区减小22.2%。提出了地面塌陷影响下的土壤水分运移调控方法:煤层开采中，通过调整工作面宽度和开采厚度，减小地面塌陷的发育程度，从而减小塌陷区土壤含水率的损失量;开采后，开展塌陷区土壤重构时，考虑不同植被的耗水特征，在植被根系土壤层下衬垫10～30 cm的黄土，可明显提升植被根系层的土壤含水率，加速矿区植被恢复进程。

The extraction of shallow buried coal seam often induces a series of ecological environment problems.Taking the shallow buried coal mine of blown-sand area as the study object,the influence of mining subsidence on soil water movement law was studied.The influence of coal mining subsidence on aeration zone structure was divided into three stages:prior to mining,the vadose zone thickness was thin,and the soil particles were relatively uniform;mining in progress,the water level dropped obviously,the vadose zone thickness increased sharply,and the homogeneity of soil particles became worse;end of mining,most of the ground fissures in blown-sand region were naturally healed,but the clay particles in the soil were reduced and the sand particles were increased,resulting in obvious soil coarsening phenomenon.Based on this definition,a two-dimensional simulation model of soil water transportation with different fissure widths was created.The results showed that the wetting front of soil water was downwards paralleled,and the soil moisture content of the same depth was essentially the same.However,the wetting front quickly moved down along the fracture and the dominant seepage phenomenon was obvious.With the increase of fissure width,the soil moisture tended to decrease while the impact radius of soil moisture tended to increase.The infiltration amount was basically irrelevant to the aeration zone thickness when aeration zone thickness was greater than the ultimate evaporation depth(300 cm),and the increasement of the aeration zone thickness only extended the time of groundwater recharge from precipitation.The field ecological investigation was also carried out in study area.The average aboveground biomass of Artemisia in mining subsidence had a reduction of 22.2% compared to normal area because of soil water shortage (insufficient water sources,the soil water content was less than 0.1 cm3/cm3) and root damage (fewer water channel,the dry root weight decreased 21.7%).The means of regulation and control for soil water movement in mining area were proposed:in order to reduce the loss of soil water content in subsidence area,the degree of fracture development would be reduced by adjusting the mining width and height in progress of mining;at the end of mining,a 10-30 cm thicknesses of loess liner laid under the soil layer was recommended when carrying out soil reconstruction in subsidence area,which could greatly improve the soil water content of vegetation root zone and accelerate the process of vegetation restoration.

1 研究区概况

2 塌陷影响下的包气带结构变异特征

3 塌陷影响下的土壤水分运移规律

   3.1 水分运移概念模型及控制方程

   3.2 计算参数及工况

   3.3 结果及分析

   3.4 土壤水分变异对植被生态的影响

4 塌陷源头减损与土壤重构

   4.1 塌陷源头减损

   4.2 土壤重构

5 结论