【作者】 宋亚新；

【导师】 张发旺； 荆恩春；

【作者基本信息】 中国地质科学院 ， 地质工程， 2007， 博士

【摘要】 神府—东胜矿区(神东矿区)位于我国西北干旱半干旱地区,生态环境脆弱,水资源天然不足。随着煤炭资源的持续开采,地表产生大面积塌陷,地下水位大幅下降,生态环境破坏问题越来越突出。如何有效利用包气带土壤水资源成为保证矿区农业植被生理需水和塌陷区生态再建的关键问题。针对神东采煤塌陷区生态再建的科学问题,以干旱区生态再建的限制性因素——包气带土壤水为出发点,通过野外地质调查、室内物理模拟试验、野外原位试验以及野外测试对神东采煤塌陷区包气带水分运移及生态环境效应进行了研究。取得的主要进展和认识如下:(1)塌陷非稳定阶段,塌陷裂隙对土壤水分散失具有重要影响,与塌陷区非裂缝带土壤水相比,塌陷裂缝部位(及塌陷裂缝发育带)土壤水分损失几乎达50%,接近或低于凋萎系数,对植被生存、生长构成威胁。(2)与非塌陷区相比,塌陷稳定区有更强的接纳降水的能力,表现在采煤塌陷稳定区土壤含水量明显高于非塌陷区,对区域生态再建有利。但在春旱季节,塌陷稳定区浅层(30cm左右)土壤储水量低于非塌陷区,对浅根系植被萌芽不利。(3)塌陷稳定阶段,地表塌陷裂缝被填充,但包气带中下部或多或少存在隐伏裂隙,但几乎不起导水作用,在对该阶段的孔隙—裂隙包气带水分运动进行模拟时,可直接利用孔隙结构体进行代替。(4)室内实验结果表明,定雨强降雨入渗过程中,细砂和粗砂中湿润锋移动都分为两个阶段:降雨期间,湿润锋前移距离与深度呈线性关系;降雨结束后(水分再分配阶段),湿润锋前移距离与深度呈幂函数关系。入渗水分迁移速度随深度增加呈指数衰减。表明塌陷稳定阶段降雨通过深厚包气带对地下水补给是一个漫长的过程。更多还原

【Abstract】 Shenfu-Dongsheng mining area is located in the arid and semi-arid region of northwest of China, with frangible entironment and deficient water resources. With the durative development of coal mine resources, it made the ground collapsing extensively and ground water level decreasing to a large extent and the geological and entironmental problem is increasingly prominent. How to use soil water resources reasonably and efficiently is highly important for physiological water requirement of vegetation and entironmental reconstruction of subsidence area. In consideration of the entironment reconstruction in Shendfu-Dongsheng subsidence area, soil water of mining area, as a limiting factor of entironment reconstruction, is focused on. Using geologic survey, physical simulation in laboratory, in situ field experiments and field measurement, this paper researches the migration of soil water and entironment effect in Shenfu-Dongsheng subsidence area. The main results are as follows:(1) In unsteady phase, ground fissures caused by collapsing facilitate the loss of soil water. The soil water content of fissure district is about 50% less than that of non-fissure district of subsidence area, which close to or below wilting coefficient. This will be a great threat for the survival and growth of vegetation.(2) Contrast to non-subsidence area, the steady subsidence area has stronger ability to accept precipitation, which can be concluded from the truth that soil water content of steady subsidence area is apparently larger than that of non-subsidence area. This will be helpful to the entironment reconstruction of subsidence area. But in dry spring, the steady subsidence area has a lower water-storing capacity in shallow layer (above 30cm) than that of non- subsidence area, which will be a disadvantage for the budding of short-root vegetation.(3) In steady phase, fissures in shallow layer of unsaturated zone are filled up, but some hidden fissures are still exist in middle and deep layer, which are no use for transmitting water in unsaturated condition. Thus, we used pore structure instead of pore-fissure structure in the simulation of soil water migration in steady phase.(4) In the condition of constant rainfall intensity, the process of wetting front moving in fine sand and coarse sand can be divided into two phases. In the first phase (i.e. during rainfall), the depth of wetting front is linear with rainfall time. In the second phase (i.e. after rainfall or the course of soil water redistribution), power function works. Migration velocity of infiltration water is an exponential decline with depth. It shows that the recharge of groundwater by rainfall needs a very long time in the condition of thick unsaturated zone in steady phase.更多还原