Study on strength influencing factors and strength model of cemented backfill with mixed aggregate

The strength of cemented backfill is one of the important indexes affecting the filling effect. There are many factors that affect the strength of cemented backfill. In order to explore the influence law of the cemented backfill strength, firstly, the strength test of cemented backfill with mixed aggregate was carried out on the basis of physical and chemical analysis of test materials and the particle size distribution analysis of mixed aggregate. Then, according to the test results, the effects of particle size distribution of mixed aggregate, solid mass concentration Cw,%, cement content Bw,%, and their interaction on the strength of backfill were analyzed. Finally, the strength model of cemented backfill with mixed aggregate was established by using industrial filling parameters such as aggregate gradation, solid mass concentration Cw,%, and cement content Bw,%, and the reliability of the model was analyzed, and the model verification test was carried out. The results show that the strength of cemented backfill is affected by single factors such as aggregate gradation, solid mass concentration Cw,%, and cement content Bw,% and is also affected by the interaction of these factors. Except for a few points, the relative error of the model is less than 10%. The verification test results show that the average relative error values of 3-day, 7-day, and 28-day strength of cemented backfill with mixed aggregate are 6.32%, 2.46%, and 0.92%, respectively, which shows that the model has a good applicability for predicting the strength of the backfill with mixed aggregate in Jinchuan mine.