| In the drainage field of the open-pit coal mine,due to the arid climate to the mining area,the vegetation growth is difficult,the soil moisture content is seriously insufficient,resulting in the degradation of the land and the deterioration of the ecosystem,and the construction of green mines has become a hot topic of current research.Therefore,by carrying out soil water evaporation loss tests and plant growth tests under the deep water replenishment mode,this thesis compared the changes of soil water holding capacity and plant growth and development under the traditional surface water replenishment mode.On this basis,combined with the near-surface soil sequence,a set of deep water replenishment system for open-pit dump was invented.The main achievements of the thesis are as follows:Based on the theory of soil water evaporation,by analyzing the change law of soil water holding capacity,daily water loss and cumulative water loss related indexes and time,it is concluded that deep water filling changes the positive and negative correlation between daily soil water loss and water holding capacity.The water evaporation rate of group T1(Surface water replenishment)is 1.3 times that of group T2(Deep hydration).Under the condition of drought,soil water will move deeper to avoid evaporation.The evaporation loss in deep water replenishment mode is much less than that in traditional surface water replenishment mode.By comparing the cumulative evaporation loss of water under different rainfall sizes,it was found that the water loss was mainly concentrated on the first day after the rainfall ended,and in the case of moderate heavy rain(2.6-15.9 mm·h),the water loss gap between T1 and T2 groups gradually increased with the increase of rainfall.On the basis of previous experiments,plant planting experiments under the condition of deep water replenishment were carried out.With the help of plant height,root length and other related indicators,it was concluded that under deep water replenishment,various growth indicators of plants were superior to traditional surface water replenishment,and the variation degree of various indicators reached medium.Among them,the fresh root weight reached 56%.By recording the water-heat change characteristics of soil in different periods,it is found that under the condition of deep water replenishment,soil moisture characteristics generally change periodically,and under the condition of no water replenishment,soil moisture decreases slowly compared with surface water replenishment,which can improve the foundation for water to stay in the soil for a long time,so as to improve the water nutrient support for plants.In the early and middle stages,at the same time point,soil temperature in the case of deep water replenishment was greater than that of surface water replenishment in the range suitable for plant growth,indicating that the influence of deep water replenishment on soil temperature was more conducive to plant growth than that of surface water replenishment.In view of the soil layer distribution of open-pit mine dump,a method was proposed to construct near-surface soil sequence from bottom to top with this layer as the bottom layer,water blocking layer,water storage and water replenishing layer,core layer,planting layer and evaporation blocking layer.On this basis,water pipeline was buried in the soil to achieve deep water replenishing,and water resource utilization efficiency was improved in arid and semi-arid areas.It plays a supporting role in the growth and development of vegetation,improves the ecological restoration effect,realizes the sustainable development of human and nature,and invented a set of mature system,which has been recognized by the state.The purpose of this system is to reconstruct the soil sequence in the dump so that water can stay in the soil longer and provide water and nutrient support for the growth and development of vegetation.The precise water replenishment is carried out directly inside the soil in a way similar to drip irrigation.The water flow driven by gas reduces the use of water resources and avoids the freezing of low-temperature water pipes in winter.In addition,in order to improve the efficiency and accuracy of the system,a total of 6 sensors are used to analyze and dynamically control water refill,and remote unmanned operation is realized.Concrete analysis of each soil layer laying,material collection and storage,buried water pipes and vegetation planting and other construction links,and Heidaigou open pit coal mine as an example,estimated construction costs and expected benefits,for the successful application of the system and spread to the open-pit mine production all over the country to lay the foundation,and for the mine environment improvement and agricultural production to bring practical help.The thesis has 36 figures,20 tables and 86 references. |
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