煤矸石基质温度场影响特征及复垦效应研究

发布时间：2018-04-22 04:29

本文选题：煤矸石温度场 + 水分空间分布　；参考：《安徽理工大学》2017年硕士论文

【摘要】：为探析煤矸石基质风化过程中温度场影响特征及复垦效应,本文通过构建不同类型的复垦复垦地块,建立土壤墒情监测基站,分层分区埋设高精度温度和湿度传感器,动态监测重构土壤水平与垂向梯度的温度及水分,分析了温度场变化机理及其影响下土壤水分的空间分布特征,并利用数学方法构建了热耦合水分迁移模型。同时通过测定了上覆土壤的理化性质指标、农作物的生理生态特性及重金属含量,评定了复垦地块土壤质量等级,分析了农作物的食品安全性,研究了污染物在农作物中的空间分布和富集特征,并进一步确定复垦效应最佳的煤矸石基质颗粒配比和覆土厚度。实验结果显示:(1)煤矸石基质在与水和大气发生物理化学反应过程中会释放热量,使得经压实后散热环境不良的煤矸石充填基质内部温度也不断积聚变化,其中以粗粒径煤矸石为充填基质的复垦地块温度场变化最为剧烈;对各复垦地块土壤温度、水分数据分析可得,重构土壤温度与水分相关性显著,在一定温度范围内,土壤水分是随着温度增加而增加,超过限值,土壤水分随土壤温度升高而降低。(2)六类复垦复垦地块的土壤水分、土壤速效养分均低于原状地块。作为充填基质的煤矸石速效养分难以释放,持水保肥能力差。综合考虑土壤质量综合指标值、小麦株高、产量以及复垦工程的生态环境效益和经济效益等方面,由数据分析可得知,煤矸石复垦地的覆土厚度选择在50cm,即可满足作物生长需求;煤矸石粒径为中粗级配比(80mm的煤矸石所占比例分别为70%)是比较合理的。(3)六类复垦地块小麦籽粒中As、Cu、Zn、Cd质量分数均低于重金属质量分数限值,处于安全水平;除Ⅵ号复垦地块Cr含量低于1.Omg/kg的重金属限值外,其余各复垦地块小麦籽粒中Cr质量分数均超标,最大值高于标准值1.83倍。各复垦地块种植的小麦籽粒中的重金属元素富集程度均低于其他器官,As、Cu、Pb、Zn、Cd、Cr等重金属元素在小麦茎中的富集程度高于其他器官。
[Abstract]:In order to analyze the influence characteristics of temperature field and reclamation effect in weathering process of coal gangue matrix, this paper establishes the base station of soil moisture monitoring by constructing different types of reclamation land, and lays high precision temperature and humidity sensors in stratified subdivision. The temperature and moisture of horizontal and vertical gradient of soil were dynamically monitored and reconstructed. The variation mechanism of temperature field and the spatial distribution characteristics of soil moisture under the influence of temperature field were analyzed, and the thermally coupled water migration model was constructed by mathematical method. At the same time, the physical and chemical properties of the overlying soil, the physiological and ecological characteristics of crops and the content of heavy metals were determined, and the soil quality grade of the reclaimed land was evaluated, and the food safety of the crops was analyzed. The spatial distribution and enrichment characteristics of pollutants in crops were studied, and the optimum proportion of coal gangue matrix particles and the thickness of overlying soil were determined. The experimental results show that the coal gangue matrix releases heat during the physicochemical reaction with water and the atmosphere, which makes the internal temperature of the coal gangue filling matrix, which has poor heat dissipation after compaction, also continuously accumulates and changes. The temperature field of reclaimed land with coarse coal gangue as filling matrix is the most dramatic, and the soil temperature of each reclamation plot can be obtained by water data analysis, and the correlation between soil temperature and water content is significant in a certain temperature range. Soil moisture increased with the increase of temperature and exceeded the limit value. Soil moisture decreased with the increase of soil temperature. The available nutrients of coal gangue as filling matrix are difficult to release, and the capacity of soil and water conservation and fertilizer conservation is poor. Considering the comprehensive index value of soil quality, wheat plant height, yield, ecological environmental benefit and economic benefit of reclamation project, it can be known from the analysis of data. The thickness of covered soil of coal gangue reclamation land is 50 cm, which can meet the demand of crop growth. The proportion of coal gangue with medium to coarse ratio of 80 mm is 70) it is reasonable. 3) the mass fraction of As-CuCuZn-Zn ~ (+) CD in wheat grain of six types of reclamation land is lower than the limit of heavy metal content, and it is at the safe level. With the exception of Cr content in reclamation plot VI being lower than the limit of 1.Omg/kg, the content of Cr in wheat grain in other reclamation plots exceeded the standard, and the maximum value was 1.83 times higher than the standard value. The enrichment degree of heavy metal elements in wheat grains planted in different reclamation plots was lower than that in other organs, such as As-CuCuPbPbPbPbPbZn-Cdzhu-Cr, in wheat stems, which was higher than that in other organs.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD849.5;TD88

【相似文献】