化石燃料消耗的不断增加，导致浅部矿产资源加速枯竭，因此，矿产资源开采逐渐向地层深部延伸已成为国家的重大发展需求，同时深部地层中所蕴含的丰富地热能也属于资源开采的范畴。矿床-地热协同开采是将充填采矿与地热资源开采相结合，利用充填体的蓄热/释热提取地热能，借助深井采矿已有条件为地热能开采的动力供应和管路布设提供保障，可有效节约地热资源开发所需的钻探和开采成本。本论文以实现深部矿产资源与地热协同开采为着眼点，以该协同体系的核心—充填体作为研究对象，对充填体蓄/释热过程及其影响因素、充填材料配比及其优化、充填材料改性处理及其蓄/释热性能等进行实验测试与分析，主要研究及结论如下：

      以相似理论为指导，搭建充填体蓄/释热模化实验台对传统充填体展开蓄/释热实验研究，分析管排布置方式、换热介质速度、围岩温度对其蓄/释热性能的影响。结果表明：随着换热管间距增加，换热介质出口水温、换热量及系统总效率都有所提升，而采用蛇形管时比采用管间距为18cm时其总能效系数更大，总能效系数增加5.5%，可见，与增加管间距相比，蛇形管因换热面积的增大更有利于热量提取。换热介质流速是影响充填体蓄/释热性能的重要因素之一，对于蛇形管排，围岩温度为45℃，流速为0.7m/s对充填体热量提取效果最佳，系统总能效系数最高，其值为46.1%。围岩温度升高会导致系统总能效系数有所降低，对于蛇形管排，流速为0.7m/s，围岩温度从35℃增加到55℃时，总能效系数从47.9%降低到44.5%，降低幅度为3.4%。

        以传统充填材料为基础，使用石墨、铜粉、铝屑粉等材料替代部分尾砂制作标准试件养护28天后对其单轴抗压强度、导热系数、比热容、密度等物性参数进行测试，实验结果表明：随着改性材料加入，标准试件的抗压强度、密度、比热容都有所降低，导热系数有所提升。不同改性材料及不同替代比例下的测试结果表明，添加10%的钢渣粉替代尾砂对试件抗压强度影响程度最小，降低幅度为14.6%。使用10%的煤气化渣替代尾砂时比热容的下降幅度较小，降低幅度为56.4%。用10%的石墨替代尾砂时对试件导热系数提升效果最佳，增加幅度为60.2%。

       通过对改性充填材料进行综合分析，选用10%的石墨替代尾砂制作缩尺模型展开蓄/释热实验研究，分析围岩温度、换热介质入口温度、充填体初始温度对蓄/释热性能的影响。由实验结果可知：进口温度降低可使充填体释热更充分，当入口温度由22℃降低至6℃时，总效率由70.4%增加到81.3%，增加幅度为10.9%。适当提高充填体初始温度，系统的总效率也得到提升，初始温度由14℃增加至26℃总能效系数增加幅度为13.3%。在同样的采热条件下，与传统充填体相比，改性充填体总能效系数提升幅度较大，当围岩温度为35℃，总能效系数提升幅度最大，为29.9%。

      本研究探索了适用于矿山-地热协同开采的管排布置模式、换热介质流速、入口水温等参数以及充填材料优化配比，揭示了改性充填材料下典型采热管排布置的传热基本特征及机理，提高了矿井充填体地下换热体系的能量利用水平，拓展和完善了充填体-采热介质之间换热的基础理论体系，为践行“矿床-地热协同开采”提供基础数据支撑。

          The increasing consumption of fossil fuels leads to the accelerated depletion of shallow mineral resources. Therefore, the gradual extension of mineral resources exploitation to deep strata has become a major national development demand; meanwhile, the rich geothermal energy contained in deep strata also belongs to the category of resource exploitation. The collaborative exploitation of deposit and geothermal energy combines backfill mining with geothermal resource mining, extracts geothermal energy by using heat storage/ release of backfill body, and provides guarantee for the power supply and pipeline layout of geothermal resources development by virtue of existing conditions of deep-well mining, which can effectively save drilling and mining costs required for geothermal resources development. In this paper, based on the collaborative exploitation of deep mineral resources and geothermal energy, taking the core of collaborative system-backfill body as the research object, the heat storage/release process of backfill body and its influencing factors, the backfill material proportion and its optimization, the modification of backfill material and the heat storage/release performance of modified backfill body are tested and analyzed. The main researches and conclusions are as follows:

           Based on similarity theory, a heat storage/release modeling test bench was built, the heat storage/release process of traditional backfill body was experimentally studied and the influence of pipe arrangement, the working fluid velocity and the  surrounding rock temperature on heat storage/release performance of backfill body was analyzed. The results indicate that the outlet temperature of working fluid, heat exchange capacity and the total efficiency of system are improved with the increase of the spacing between heat transfer pipes. The total energy efficiency coefficient of serpentine pipes is 5.5% higher than that of pipe spacing of 18cm. The increase of heat transfer area of serpentine pipe is more conducive to heat extraction than the increase of pipe spacing. The total energy efficiency coefficient has increased by 5.5%. The velocity of heat transfer medium is one of the important factors affecting the heat storage/release performance of backfill body. For the serpentine pipe, when the surrounding rock temperature is 45℃ and the velocity of 0.7m/s, the maximum heat is extracted from the  backfill body, and the total energy efficiency coefficient of the system is the highest of 46.1%. The increase of surrounding rock temperature leads to a decrease in the total energy efficiency coefficient of system. For the serpentine pipe, when the surrounding rock temperature increases from 35℃ to 55℃, the total energy efficiency coefficient decreases from 47.9% to 44.5%, with a reduction of 3.4%.

             Based on traditional backfill materials, graphite, copper powder, aluminum powder and other materials were used to replace part of the tailings and  thestandard specimens were prepared. After 28 days of curing, the uniaxial compressive strength, mini-slump, thermal conductivity, specific heat capacity, density and other physical parameters were tested. The experiment results show that the compressive strength, density and specific heat capacity of the standard specimens are reduced and the thermal conductivity is increased with the addition of modified materials. The test results of different modified materials and different substitution ratios showed that adding 10% steel slag powder instead of tailings has the weakest effect on the compressive strength of the specimen, with a reduction of 26.8%. When the mass ratio 10% of coal gasification slag is used to replace the tailings, the decrease of specific heat capacity is the least, with a reduction of 56.7%. When the mass ratio 10% of graphite is used to replace the tailings, the thermal conductivity of the specimens can be maximized by 60.2%.

        Based on the comprehensive analysis of the modified backfill materials, the mass ratio 10% of graphite was selected to replace the tailings to make a scale model and the heat storage/release experiment was carried out. The influences of surrounding rock temperature, inlet temperature of working fluid and initial temperature of backfill body on heat storage/release performance were analyzed. According to the experimental results, the decrease of the inlet temperature of working fluid can make the backfill body release heat more fully. When the inlet temperature decreases from 22℃ to 6℃, the total efficiency of the system increases from 70.4% to 81.3%, with an increase of 10.9%. The total efficiency is also improved with the appropriate increase of the initial temperature of backfill body. When the initial temperature increases from 14℃ to 26℃, the total efficiency increases by 13.3%. Under the same heat extraction conditions, compared with the traditional backfill body, the total energy efficiency coefficient of the modified backfill body improves greatly. When the surrounding rock temperature is 35℃, the total energy efficiency coefficient increases by 29.9% at the maximum.

        In this study, the parameters such as the pipe arrangement, the velocity and inlet temperature of working fluid, the temperature of surrounding rock and the optimization ratio of backfill materials suitable for the collaborative exploitation of deposit and geothermal energy were explored. The basic characteristics and mechanism of heat transfer for typical pipe arrangement under modified backfill materials were revealed. The energy utilization level of underground heat exchange system of backfill body in mine was improved, the basic theoretical system of heat transfer between backfill body and heat recovery medium was expanded and perfected. The results provide the theoretical support for the practice of collaborative exploitation of deposit and geothermal energy.

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