某金矿全尾砂充填体早期强度性能分析

Analysis on the Early Strength of Backfill with Unclassified Tailings in a Gold Mine

针对某金矿以水泥为主要胶凝材料造成的充填成本高、早期强度低的问题,以该金矿全尾砂为骨料,选用生石灰、石膏、水淬矿渣、水泥为辅料,在分析全尾砂物化性质的基础上,采用全面法试验设计,制备料浆质量浓度为70%、72%、74%、76%和灰砂比1∶4,1∶6,1∶10和1∶20的充填料浆,测定养护龄期为1,3,7,14d时抗压强度。结合Design-Expert软件筛选并评估影响全尾砂充填体早期强度的显著性因素。试验结果表明:料浆质量浓度和养护龄期一定时,充填体早期强度与灰砂比表现为正比关系;控制养护龄期和灰砂比不变,随着料浆质量浓度的增大,充填体强度增长越明显;在灰砂比和料浆质量浓度相同的条件,充填体强度与养护龄期呈正相关,对充填体早期强度影响敏感性顺序为灰砂比>养护龄期>料浆质量浓度。通过试验可知,在灰砂比1∶4,料浆质量浓度76%时,充填体1d强度可达0.76MPa,3d强度可达1.19 MPa,7d强度可达2.09 MPa,14d强度可达2.21 MPa。将试验结果应用于工程实践,可为矿山充填提供理论依据和数据参考。

In view of the problems of high filling cost and low early strength caused by cement as the main cementitious material in a gold mine,the unclassified tailings of the gold mine was used as aggregate,and quicklime,gypsum,water quenched slag and cement were selected as auxiliary materials.Based on the analysis of physical and chemical properties of the unclassified tailings,a comprehensive test design was adopted to prepare slurry with mass concentration of 70%,72%,74%and 76%,as well as cement-sand ratio of 1:4,1:6,1:10 and 1:20.The compressive strength of backfill at curing ages of 1,3,7,14 days was measured.Design-Eexpert software was used to screen and evaluate the significant factors that affect the early strength of the backfill with unclassified tailings.The test results showed that the early strength of the backfill was in direct proportion to the cement-sand ratio when the slurry mass concentration and curing age were fixed,and it would increase more obviously with the increase of slurry mass concentration when the curing age and the cement-sand ratio were constant.Under the same slurry mass concentration and the cement-sand ratio,the strength of the backfill was positively related to the curing age.The sensitivity order affecting the early strength of backfill was the cement-sand ratio>curing age>slurry mass concentration.According to the test,when the cement-sand ratio was 1,4 and the slurry mass concentration was 76%,the strength of backfill can reach 0.76 MPa,1.19 MPa,2.09 MPa,and 2.21 MPa in 1,3,7,and 14 days respectively.The application of test results to engineering practice can provide theoretical basis and data reference for mine filling.