矿用湿式喷射混凝土配合比优化设计及实验研究

发布时间：2019-06-04 05:53

【摘要】：矿井巷道利用湿式喷射混凝土(以下简称湿喷混凝土)进行支护具有降低工作面粉尘浓度、减少回弹、提高喷射质量和支护效果等优点。对改善矿井掘进、支护工作条件,保障安全、健康生产具有重要意义。但是,湿喷混凝土在泵送过程中易出现管道堵塞问题,甚至出现爆管等严重威胁安全生产的问题。而且,湿喷混凝土作业粉尘浓度还有待进一步降低,以保证职工健康。这些都是矿井安全生产工作非常重要的部分。因此,本文通过对配合比进行优化设计,进而得到作业过程中粉尘浓度较小、职业危害较低,泵送、喷射和支护效果均较好的湿喷混凝土。运用理论分析、试验研究、安全评价方法优化和现场应用等多种手段,研究矿用湿喷混凝土最优的配合比设计。详细分析了原材料的种类、用量对湿喷混凝土工作性、可泵性、可喷敷性、产尘分析和经济性的影响,不但得到了适用于湿喷混凝土配合比设计所需原材料种类和用量的范围,而且找到了对湿喷混凝土配合比设计影响较大的五种因素(用水量;水灰比;砂率;速凝剂添加量;和聚丙烯纤维长度)。设计五因素四水平共16组配合比的正交实验,在保证强度的基础上,用坍落度表示流动性,用压力泌水率表示粘聚性,用我们课题小组自主研发的泵送压力实验平台测定的压降表示可泵性。通过正交实验分析,分别得到五种因素与湿喷混凝土性能的相关性曲线,并且从16组配合比中优选出两组实验效果较好的配合比。利用优选出的两组配合比重新调整得到五组新的配合比,进一步研究湿喷混凝土的可喷敷性、产尘分析和经济性。分别进行回弹率测定、粉尘浓度测定和经济性计算,从五组配合比中选出最优的三组配合比。借助安全评价方法中的层次分析法对配合比进行精选,以最优配合比为总目标、以可喷敷性、产尘分析和经济性为判断层、以三组配合比为方案层进行理论分析,其中根据经验及实际情况我们选择三种性能的重要度排序为:可喷敷性经济性产尘分析。通过分析比较最终精选出一组最优的配合比。在相关实验和分析的基础上,于某矿井进行现场效果检测,保证工艺技术条件、喷射相关特征参数以及原材料的种类等条件一致的情况下,分别按照精选出的配合比和目前使用的配合比进行应用,检验最优配合比的的效果。
[Abstract]:The use of wet shotcrete (hereinafter referred to as wet shotcrete) for support in mine roadway has the advantages of reducing dust concentration in working face, reducing springback, improving spray quality and supporting effect. It is of great significance to improve mine excavation, support working conditions, ensure safety and healthy production. However, wet shotcrete in the pumping process is prone to pipeline blockage, and even pipe explosion and other serious threats to safety in production. Moreover, the dust concentration in wet shotcrete operation needs to be further reduced to ensure the health of workers. These are very important parts of mine safety work. Therefore, by optimizing the mix design, this paper obtains the wet shotcrete with low dust concentration, low occupational harm and good pumping, spraying and supporting effects in the process of operation. The optimal mix proportion design of mining wet shotcrete is studied by means of theoretical analysis, experimental research, optimization of safety evaluation method and field application. The effects of raw materials and dosage on the workability, pump ability, spraying ability, dust production analysis and economy of wet shotcrete are analyzed in detail, and the range of raw materials suitable for wet shotcrete mix proportion design is obtained. Five factors (water consumption) which have great influence on the mix proportion design of wet shotcrete are found. Ratio of water to cement; sand ratio; amount of accelerator; and length of polypropylene fiber). The orthogonal experiment of 16 groups of mix proportion with five factors and four levels was designed. On the basis of ensuring strength, slump was used to represent liquidity and pressure bleeding rate was used to indicate cohesion. The pump performance is expressed by the pressure drop measured by the pumping pressure experimental platform developed by our project group. Through orthogonal experimental analysis, the correlation curves between five factors and the performance of wet shotcrete are obtained, and the better mix proportion of the two groups is selected from 16 groups of mix proportion. Five groups of new mix ratios were obtained by adjusting the optimized mix proportion of the two groups, and the spraying property, dust production analysis and economy of wet shotcrete were further studied. The springback rate, dust concentration and economy were measured, and the optimal three groups were selected from the five groups. With the help of the analytic hierarchy process (AHP) in the safety evaluation method, the mix proportion is selected, the optimal mix ratio is taken as the overall goal, the spraying ability, dust production analysis and economy are taken as the fault judgment, and the three groups of mix ratios are taken as the scheme layer for theoretical analysis. According to the experience and actual situation, we choose the importance of three kinds of performance as follows: injectable economic dust production analysis. Through analysis and comparison, a group of optimal mix ratios are selected. On the basis of relevant experiments and analysis, the field effect test is carried out in a mine to ensure that the technological and technical conditions, the jet related characteristic parameters and the types of raw materials are consistent. According to the selected mix ratio and the current mix ratio, the effect of the optimal mix ratio is tested.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD353

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