摘要
针对煤层回采顶板垮落法产生的采煤固废堆放量大、长壁胶结充填开采中采充失衡等问题,内蒙古察哈素煤矿31采区采用连采连充巷式胶结充填采煤工艺,采用“隔三采一”的回采方式及“三强一弱”的充填模式。充填材料配比对充填成本与效果具有重要影响,针对原胶结充填材料中水泥消耗大、粉煤灰消纳少的问题,基于泰波理论确定矸石最佳粒径级配系数n为0.5,在此基础上,利用响应面法(RSM)优化材料配比。基于RSM-BBD (Box–Behnken Design)设计13组试验,建立充填体3、7及28 d单轴抗压强度与水泥质量分数X_(1)、粉煤灰质量分数X_(2)、固料质量分数X_(3)及3因素交互作用(水泥与粉煤灰交互作用X_(1)X_(2)、水泥与固料质量分数交互作用X_(1)X_(3)、粉煤灰与固料质量分数交互作用X_(2)X_(3))的回归模型,模型P值均小于10-4,模型可靠性强。试验结果表明:不仅单一因素对强度影响显著,且各因素的交互作用也对强度有一定的影响。强度随X_(1)与X_(3)的增加而增大,随X_(2)的增加先增大后减小,X_(1)对前期影响最显著,X_(3)对后期影响最显著,X_(2)对强度影响随龄期增长逐渐显著。X_(2)X_(3)对7 d强度影响显著,X_(1)X_(2)对28 d强度影响显著,X_(1)X_(3)对3、7和28 d强度均有显著影响。在X_(1)X_(3)对7、28 d强度的交互影响中,水泥与固料质量分数会相互促进两者对强度的增强作用,而在其他交互影响中,一因素的增加会对另一因素的影响效果起抑制作用。基于RSM确定合理配比为X_(3)取78%~79%, X_(2)取19%~20%;高强度充填时X_(1)取9%~10%,低强度充填时X_(1)取8%。察哈素煤矿303工作面共采出煤炭16.8万t,消纳矸石16.22万t,粉煤灰消纳增加量与水泥消耗减少量均达到1万t以上,大大节省了粉煤灰处理费用与水泥成本,具有良好的环境效益与经济效益。
In view of the problems of large stacking of solid waste caused by roof caving method in coal seam mining and imbalance between mining and filling in long-wall cemented backfilling,the No.31 ming area of Chahasu Coal Mine in Inner Monogolia uses continuous mining and filling roadway cemented backfilling mining technology,adopting the“mining at intervals of three”mining method and the“three with high strength filling and one with low strength filling”filling mode.The filling material ratio has an important influence on the filling cost and effect.In order to solve the problems of high cement consumption and less absorption of fly ash utilization in the original cemented filling materials,the optimal particle size grading coefficient n of gangue was determined based on Talbot gradation theory as 0.5,and material ratio was optimized using the Response Surface Method(RSM).Based on Box–Behnken Design(RSM-BBD)of 13 groups of tests,a regression models of the single-axis compressive strength of the backfilling body at 3,7 and 28 days with the cement mass fraction X_(1),fly ash frection X_(2) and solid mass fraction X_(3),and the interaction of the three factors(X_(1)X_(2),X_(1)X_(3),and X_(2)X_(3))was establish ed.The P values of the models were all less than 10−4,which indicates that the model has strong reliability.The test results show that not only does the single factor has a significant effect on the strength,but the interaction of factors also has a certain impact on the strength.Specifically,the strength of backfill increases with the increase of X_(1) and X_(3),but increases first and then decreases with the increase of X_(2).Besides,X_(1) has the most significant effect in the early stage,X_(3) has the most significant effect in the later stage,while the effect of X_(2) on the strength gradually becomes significant as the age period increases.X_(2)X_(3) influences the 7-day strength of backfill significantly,X_(1)X_(2) influences the 28-day strength significantly,and X_(1)X_(3) has a significant effect on the strength at 3,7 and 28 days.In the interaction effect of X_(1)X_(3) on the strength of backfill at 7 and 28 days,the content and mass concentration of cement promote each other,capable of increasing the strength,while in the interaction,the increase of one factor will have an inhibitory effect of the other.Base on RSM,the reasonable ratio was determined as X_(3) at 78%‒79%,X_(2) at 19%‒20%;X_(1) at 9%‒10%for high strength filling,and X_(1) at 8%for low strength filling.The No.303 working face of Chahasu Coal Mine mined a total of 1.68×105 tons of coal,and consumed 1.622×10^(5) tons of gangue,with an increase of fly ash utilization and an decrease of cement consumption of more than 1.0×10^(4) t,greatly saving of fly ash treatment and cement cost,bringing good environmental and economic benefits.
作者
王树帅
徐斌
李杨
杨震
WANG Shushuai;XU Bin;LI Yang;YANG Zhen(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2023年第3期73-84,共12页
Coal Geology & Exploration
基金
国家自然科学基金项目(51804310)
国家自然科学基金面上项目(52174095)。
关键词
连采连充
巷式胶结充填
响应面RSM
优化材料配比
交互作用
工程应用
内蒙古察哈素煤矿
continuous mining and filling
roadway cemented backfilling
Response Surface Method(RSM)
optimization of material ratio
interaction term
engineering application
Chahasu Coal Mine in Inner Mongolia
