基于SVM的粗骨料膏体性能预测及优选方法

Coarse aggregate paste performance prediction and proportioning optimization method based on SVM

膏体充填能够改变矿区周围岩石的应力状态,减少矿区周围的环境问题,在国内外地下矿山得到广泛应用。膏体合理配比的确定需要进行大量实验,亟需寻找一种简单有效的方法去对膏体的性能进行预测。对此,本文开展了27组配比的强度和坍落度测试,采用PSO、Grid和GA算法优化后的支持向量机(SVM)进行训练,对比分析预测结果对算法进行优选。基于算法模型进行膏体性能预测,采用极差分析手段揭示了不同影响因素对充填体性能的影响,最后采用线性规划原理得到了最佳配比参数。结果表明:核函数的参数c和惩罚系数g随算法不同而变化,不能作为评判预测精度的依据。Grid算法和PSO算法可以分别对坍落度和强度进行精准预测。由于膏体中自由水含量的影响导致坍落度受粗骨料-尾砂比和浓度的影响较大。不同龄期条件下水泥掺量和浓度对充填体强度的影响始终处于主导地位,随着龄期增加粗骨料“骨架”效应逐渐显现。以金川矿山实际充填需求为例,获得其最低成本配比条件为水泥掺量为280 kg/m~3,粗骨料-尾砂质量比为1∶1,废石-棒磨砂比为1∶1.44。

Paste filling can change the stress state of the rocks around the mine and reduce the environmental problems around the mine, which is widely used in underground mines at home and abroad. The determination of paste’s reasonable ratio requires a lot of experiments, and there is an urgent need to find a simple and effective method to predict the paste performance. Thus, strength and slump tests of 27 sets were conducted in this paper,and the SVMs optimized by PSO, Grid, and GA algorithms were trained to compare the prediction results for algorithm optimization. Then the paste performance prediction was carried out based on the corresponding model,and the influence degree of different factors on the paste performance was revealed using extreme difference analysis. Finally, the optimal proportioning parameters were obtained by using the linear programming principle.The results show that the parameter c and the penalty coefficient g vary with the algorithm and cannot be used as a basis for judging the prediction accuracy. Grid algorithm and PSO algorithm can make accurate predictions of slump and strength respectively. Because of free water content in paste, the slump is mainly influenced by the coarse aggregate-to-tailing ratio and concentration. At the same time, the influence of cement content and concentration on the strength of the filler under different age conditions is always dominant. Moreover, the “skeleton” effect of coarse aggregates gradually appears with the curing age increase. The lowest cost ratio to meet the actual filling requirements of Jinchuan mine is 280 kg/m~3 of cement, a coarse aggregate-tailing mass fraction ratio of 1∶1, and a waste rock-rod mill sand ratio of 1∶1.44.