废石胶结充填体配比优化及与围岩合理匹配研究

Study on Proportion Optimization of Waste Rock Cemented Filling Body and Reasonable Matching with Surrounding Rock

为研究废石胶结充填体的孔隙特征和强度变化规律,对不同灰砂比和不同废石粒径比的废石胶结充填体进行了核磁共振和单轴压缩试验,基于能量释放与耗散原理,将室内废石胶结充填配比试验与贵州长田簸箕田1#矿实际开采情况相结合,分析废石胶结充填体与围岩的匹配程度。结果表明,充填体灰砂比大于1∶3时,充填体的孔径分布和孔隙度对废石粒径比不敏感,灰砂比小于1∶3时,充填体的孔径分布和孔隙度受废石粒径比作用显著;随着灰砂比的减小,充填体的单轴抗压强度呈先增大后减小的趋势,废石胶结充填体灰砂比为1∶2时,其单轴抗压强度达到最高值;在相同灰砂比的充填体中,废石粒径比3∶2为最优配比。基于上述试验结果,通过充填体损伤理论对充填体的变形能进行进一步分析计算,并结合贵州长田簸箕田1#矿围岩开挖实际情况,将试验中第9组废石胶结充填体(灰砂比为1∶3,废石粒径比为3∶2)应用到该矿最合理。

In order to study the pore characteristics and strength variation law of waste rock cemented filling body,nuclear magnetic resonance and uniaxial compression tests were carried out on waste rock cemented filling bodies with different cementsand ratios and different particle size ratios of waste rock.Based on the principle of energy release and dissipation,the indoor waste rock cemented filling proportion test was combined with the actual mining situation of 1#mine in Bojitian,Changtian,Guizhou to analyze the matching degree of waste rock cemented filling body and surrounding rock.The results show that when the cement-sand ratio of the filling body is greater than 1∶3,the pore size distribution and porosity of the filling body are not sensitive to the particle size ratio of the waste rock.When the cement-sand ratio is less than 1∶3,the pore size distribution and porosity of the filling body are significantly affected by the particle size ratio of waste rock.With the decrease of cement-sandratio,the uniaxial compressive strength of the filling body increases first and then decreases.When the cement-sand ratio ofwaste rock cemented filling body is 1∶2,the uniaxial compressive strength reaches the highest value.In the filling body withthe same cement-sand ratio,the particle size ratio of waste rock of 3∶2is the optimal.Based on the above test results,thedeformation energy of the filling body is further analyzed and calculated by the filling body damage theory.Combined with theactual situation of surrounding rock excavation in 1# mine of Bojitian,it is the most reasonable to apply the 9th group(cementsand ratio 1∶3and particle size ratio of waste rock 3∶2)in the test to the mine.