深地开采, 膏体先行

为解决充填膏体成本高昂的问题，将污泥作为骨料制备充填膏体。采用正交试验方法，进行污泥膏体充填材料配比试验，探讨污泥质量分数、水泥质量分数、粉煤灰质量分数对充填膏体坍落度、凝结时间、抗压强度的影响。在此基础上，以污泥质量分数、水泥质量分数、粉煤灰质量分数为自变量影响因子，充填膏体抗压强度为响应目标值，结合响应面法(RSM)，建立污泥充填膏体抗压强度预测模型，揭示多目标条件下污泥膏体充填材料优化配比。研究结果表明，污泥充填膏体强度不仅受单个因素影响，而且受多个因素间交互作用影响显著。其中污泥质量分数和水泥质量分数的交互作用是影响充填膏体强度性能的关键性因素。优化的充填材料配比：充填料浆质量分数75%，石灰质量分数4%；污泥质量分数8.32%，水泥质量分数29.62%，粉煤灰质量分数20.33%。经试验验证，该配比条件下充填膏体各龄期抗压强度均满足设计要求。

Strength development and microstructural investigation of lead-zinc mill tailings based paste backfill with fly ash as alternative binder

In order to solve the problem of high cost of filling paste, sludge was used as aggregate to prepare filling paste. The orthogonal test method was adopted to carry out the proportion test of sludge paste filling materials, and the influence of sludge mass fraction, cement mass fraction and fly ash mass fraction on the slump, setting time and compressive strength of filling paste was discussed. On this basis, sludge mass fraction, cement mass fraction and fly ash mass fraction were taken as independent variables and the compressive strength of the filling paste was taken as the target value. Combined with response surface methodology (RSM), a prediction model for the compressive strength of the sludge filling paste was established to reveal the optimal ratio of sludge paste filling materials under multi-objective conditions. The results show that the strength of sludge filling paste is not only affected by single factor, but also significantly affected by the interaction among factors. The interaction between sludge mass percentage concentration and cement mass fraction is the key factor affecting the strength performance of filling paste. The optimized filling material ratio is as follows: the slurry mass fraction is 75%, and the lime mass fraction is 4%; the sludge mass fraction is 8.32%, and the cement mass fraction is 29.62%; the fly ash mass fraction is 20.33%. The test verifies that the compressive strength of the filling paste at all ages meets the design requirements under the ratio condition.