(1. 石家莊鐵道大學(xué) 省部共建交通工程結(jié)構(gòu)力學(xué)行為與系統(tǒng)安全國(guó)家重點(diǎn)實(shí)驗(yàn)室，石家莊 050043；
2. 石家莊鐵道大學(xué) 河北省金屬礦山安全高效開(kāi)采技術(shù)創(chuàng)新中心，石家莊 050043；
3. 石家莊鐵道大學(xué) 安全工程與應(yīng)急管理學(xué)院，石家莊 050043；
4. 北京科技大學(xué) 土木與資源工程學(xué)院，北京 100083；
5. 石家莊鐵道大學(xué) 道路與鐵道工程安全保障省部共建教育部重點(diǎn)實(shí)驗(yàn)室，石家莊 050043)
摘 要: 為了模擬與現(xiàn)場(chǎng)膏體充填體(CPB)較為相近的養(yǎng)護(hù)環(huán)境，分析養(yǎng)護(hù)壓力對(duì)其強(qiáng)度的影響機(jī)理，以某銅礦全尾砂為研究對(duì)象，研究養(yǎng)護(hù)壓力和養(yǎng)護(hù)時(shí)間對(duì)膏體充填體強(qiáng)度的影響規(guī)律。采用掃描電鏡觀察膏體充填體的微觀結(jié)構(gòu)，并對(duì)掃描電鏡圖像進(jìn)行二值化處理，應(yīng)用分形理論從定量角度對(duì)其機(jī)理進(jìn)行分析。結(jié)果表明：隨著養(yǎng)護(hù)壓力的增加，膏體充填體的強(qiáng)度呈一元二次函數(shù)增長(zhǎng)，但增長(zhǎng)的速率逐漸減小，且膏體充填體的強(qiáng)度隨養(yǎng)護(hù)時(shí)間的延長(zhǎng)逐漸增加；膏體充填體的計(jì)盒維數(shù)隨養(yǎng)護(hù)壓力的增大而增大。養(yǎng)護(hù)壓力對(duì)膏體充填體強(qiáng)度的影響機(jī)理在于：由于養(yǎng)護(hù)壓力的增加，使孔隙水壓力消散，水化反應(yīng)加快，孔隙被水化產(chǎn)物所填充，使膏體充填體內(nèi)部孔隙減小，形成新的膏體充填體承載骨架，進(jìn)而使膏體充填體強(qiáng)度增加。
關(guān)鍵字: 膏體充填體；養(yǎng)護(hù)壓力；強(qiáng)度；微觀結(jié)構(gòu)；分形維數(shù)
（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
