(1. 石家庄铁道大学 省部共建交通工程结构力学行为与系统安全国家重点实验室，石家庄 050043；
2. 石家庄铁道大学 河北省金属矿山安全高效开采技术创新中心，石家庄 050043；
3. 石家庄铁道大学 安全工程与应急管理学院，石家庄 050043；
4. 北京科技大学 土木与资源工程学院，北京 100083；
5. 石家庄铁道大学 道路与铁道工程安全保障省部共建教育部重点实验室，石家庄 050043)
摘 要: 为了模拟与现场膏体充填体(CPB)较为相近的养护环境，分析养护压力对其强度的影响机理，以某铜矿全尾砂为研究对象，研究养护压力和养护时间对膏体充填体强度的影响规律。采用扫描电镜观察膏体充填体的微观结构，并对扫描电镜图像进行二值化处理，应用分形理论从定量角度对其机理进行分析。结果表明：随着养护压力的增加，膏体充填体的强度呈一元二次函数增长，但增长的速率逐渐减小，且膏体充填体的强度随养护时间的延长逐渐增加；膏体充填体的计盒维数随养护压力的增大而增大。养护压力对膏体充填体强度的影响机理在于：由于养护压力的增加，使孔隙水压力消散，水化反应加快，孔隙被水化产物所填充，使膏体充填体内部孔隙减小，形成新的膏体充填体承载骨架，进而使膏体充填体强度增加。
关键字: 膏体充填体；养护压力；强度；微观结构；分形维数
（1. State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang 050043, China;
2. Hebei Technology and Innovation Center on Safe and Efficient Mining of Metal Mine, Shijiazhuang Tiedao University, Shijiazhuang 050043, China;
3. School of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang 050043, China;
4. School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China;
5. Key Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Shijiazhuang 050043, China）
Abstract:To simulate the similar curing environment of field condition for cemented paste backfill(CPB) materials, and to analyze the influence of curing stress on the strength of CPB materials, the total tailings in one copper mine was selected as the research object, the effects of the curing stress and curing time on the strength of CPB materials were studied. The scanning electron microscope was used to observe the microstructure of cemented paste backfill materials, and the computer image processing technology was applied for the binary processing for the SEM image, then the fractal dimension method was adopted to analyze the compressive strength mechanism. The results show that the strength of CPB materials increases with the increase of the curing stress, and it shows the quadratic function of one variable, also the strength increases significantly with the increase of curing time. The box-counting dimension increases with the increase of curing stress. The mechanism for the influence of curing stress on the strength of CPB materials is that, with the increase of curing stress, the porosity decreases greatly due to the dissipation of pore water pressure, and the hydration reaction increases, the pores are filled by the hydration products, also the pores are decreased for the CPB, forming the new bearing frame of CPB materials, which resulting in the increase of strength for CPB materials.
Key words: cemented paste backfill materials; curing stress; strength; microstructure; fractal dimensions
