露天煤矿剥离物不同配比表土替代材料的物理性质

Physical Properties of Topsoil Substitute Materials Formed by Overburden Materials in Open-pit Coal Mine with Different Ratios

[目的]探究利用不同配比露天煤矿剥离物制备的表土替代材料物理性质特征,为露天矿表土替代材料研发及剥离物综合利用提供理论依据。[方法]以蒙东地区某露天煤矿矿山剥离物为研究对象,使用环刀法、激光粒度仪及X射线荧光光谱测定表土替代材料容重、孔隙度、田间持水量、粒径、比表面积及其组成,运用灰色关联及主成分分析法分析了物理性质间的关系,探究影响表土替代材料物理性质的核心指标,筛选适宜的表土替代材料配比。[结果]①影响表土替代材料物理性质的两个重要指标分别为容重和田间持水量,影响表土替代材料持水能力的重要指标是微粒比表面积和总孔隙度;②心土(钙层土)及细砂的比例增高30%,将导致表土替代材料持水能力下降22%;③影响表土替代材料容重的重要指标是粒径跨度和D 10;④5A(下泥岩段:上泥岩段:底板土:心土:沙=3∶3∶4∶1∶2)和7A(下泥岩段:上泥岩段:底板土:心土:沙=2∶1∶2∶2∶2)处理容重和持水能力均较好,为最优表土替代材料配比。[结论]通过调节露天煤矿剥离物配比可以有效改善矿山表土替代材料物理性质,在表土替代材料配置过程中应提高泥岩和底板土的比例并降低钙层土比例来提高持水能力,露天煤矿剥离物表土替代材料适宜的容重配比为泥岩∶生土∶沙=2∶2∶1。

[Objective]The physical properties of topsoil substitute materials formed by overburden materials in the open-pit coal mine with different ratios were explored,in order to provide a theoretical basis for the development of topsoil substitute materials and comprehensive utilization of stripping materials in open-pit coal mines.[Methods]Taking the stripping material of an open-pit coal mine in Eastern Inner Mongolia as the research object,the bulk density,porosity,field capacity,particle size,specific surface area and composition of topsoil substitute materials were determined by cutting ring method,laser particle size analyzer and X-ray fluorescence spectrometry.The relationships between physical properties of topsoil substitute materials were analyzed by the grey relational analysis and principal component analysis,and the core indexes affecting the physical properties of topsoil substitute materials were analyzed to obtain the most appropriate ratio of topsoil substitute materials.[Results]①The two important indexes affecting the physical properties of topsoil substitute materials were bulk density and maximum field capacity,while the main indexes influencing the field capacity were specific surface area and total porosity of particles.②The increase of the proportion of heart soil(Calcium layer soil)and fine sand by 30%,would lead to the decrease of the field capacity of topsoil substitute material by 22%.③Diameter span and D10 were the key indexes determining the bulk density of topsoil substitute materials.④5A(lower mudstone∶upper mudstone∶floor soil∶heart soil∶sand=3∶3∶4∶1∶2)and 7A(lower mudstone∶upper mudstone∶floor soil∶heart soil∶sand=2∶1∶2∶2∶2)had better bulk density and field capacity,both of them were the optimal substitute material ratio for the topsoil in this test.[Conclusion]The physical properties of topsoil substitute materials can be effectively improved by adjusting the ratio of overburden materials in open-pit coal mines.In the preparation process of topsoil substitute materials,the proportion of mudstone and floor soil should be increased and the proportion of calcium layer soil should be decreased to strengthen the water holding capacity.The suitable bulk density ratio of topsoil substitute materials formed by overburden materials in open-pit coal mines is mudstone∶raw soil∶sand=2∶2∶1.