掺石灰石粉的胶结充填体强度研究

Study on Strength of Cemented Backfill with Limestone Powder

为揭示石灰石粉掺量、胶凝材料添加量和质量浓度对胶结充填体强度的影响规律,建立掺石灰石粉的充填体强度的计算模型。首先通过物化试验证实石灰石粉和废石均可满足骨料使用标准;根据级配试验获得废石和石灰石粉的不均匀系数和曲率系数,结合土力学标准,由不均匀系数可知废石级配中缺少细骨料,极易被压实,孔隙率较大,影响充填体强度;开展不同石灰石粉掺量、胶凝材料添加量和质量浓度的3 d、7 d和28 d充填体强度试验,通过方差分析确定各影响因素与充填体强度的关系为正相关,增加石灰石粉掺量可有效提高不同龄期充填体强度;最后以一元非线性理论为基础,利用SPSS曲线估计建立各龄期充填体强度多元非线性模型,各龄期强度计算模型的平均绝对误差为0.389,0.0575和0.18,模型预测精度较高,对石灰石粉工业应用具有一定指导意义。

In order to reveal the influence law of the limestone powder content,cementitious material content and the mass concentration on the strength of cementitious backfill,the calculation model for the strength of cemented backfill with limestone powder was established.Firstly,through physical and chemical test analysis,it was confirmed that both limestone powder and waste rock can meet the aggregate usage standards.According to the grading test,the uneven coefficient and curvature coefficient of waste rock and limestone powder were obtained.Combined with the soil mechanics standard,it could be known from the variation factor that there was a lack of fine aggregate in the grading of waste rock,which was easy to be compacted and has a large porosity,so as to affect the backfill strength.Strength tests of backfill at 3 d,7 d and 28 d with different limestone powder contents,cementitious materials contents and mass concentrations were carried out.Through variance analysis,it was found that the relationship between each influencing factor and backfill strength was positively correlated.Increasing the limestone powder content could effectively improve the backfill strength at different ages.Finally,based on the unitary nonlinear theory,the SPSS curve was used to establish the multivariate nonlinear model of the backfill strength at each age.The average absolute error of the strength calculation model at each age was 0.0389,0.0575 and 0.18,with a relatively high prediction accuracy.The study has a certain guiding significance for the industrial application of limestone powder.