基于RSM-BBD的废石-风砂胶结体配合比与强度试验研究

充填料浆配合比的选择直接决定了充填体的强度及运行成本。根据两种骨料混合堆积密实度试验,得到废石风砂最优配比。利用Design-Expert软件中的Box-Behnken中心组合试验设计及响应面法(RSM)研究了料浆质量分数、水泥用量和骨料配比对充填体不同龄期内无侧限抗压强度的影响规律,建立了以粗骨料胶结体3,7,28 d强度为响应值的三元二次回归模型,并对该模型的适用性进行了验证。试验结果表明,充填体强度不仅受单一因素影响,而且两因素之间的交互作用对强度影响显著。由模型的响应曲面可知,质量分数与骨料配比的交互作用对充填体早期强度影响显著,水泥用量与骨料配比的交互作用对充填体中期强度影响显著,质量分数与水泥用量的交互作用对充填体后期强度显著。通过回归模型及建立的充填材料成本函数,优选出一组料浆配合比,经现场试验满足生产要求。

Experimental research on mix proportioning and strength of cemented hydraulic fill with waste rock and eolian sand based on RSM-BBD

The selection of cement-tailings ratio directly determines both the strength of the filling body and the running cost of a mine.The optimum ratio of waste rock and aeolian sand is obtained according to the packing density test of two kinds of mixed aggregates.Using Box-Behnken design and response surface methods (RSM) in Design-Expert software,the influence laws of the slurry concentration,dosage of cement and aggregate ratio on the strength properties of cemented hydraulic fill (CHF) at different ages are studied.Two order polynomial regression model with three factors is established,in which the strengths of 3 days,7 days and 28 days are used as response values.And the suitability of the regression model has been verified.The research shows that the strength of the filling body is not only affected by single factor,and the interaction between the two factors is also significant.According to the response surface,the initial,medium and post strength of backfill body are remarkably affected by the interaction of the slurry mass concentration and aggregate ratio,cement content and aggregate ratio and the slurry mass concentration and cement content respectively.By the regression model and the cost function of backfill materials,a set of optimum slurry mixture ratio is obtained,and the field test has proven that it can meet the requirement of production.