基于“两介质-三界面”模型的散煤注浆固结宏细观规律

为了预判水泥浆注浆加固淮北矿区松散煤层效果,提供合理注浆参数,确保松散破碎围岩体注浆加固后稳定,文章基于离散元思想,将散煤和水泥视为颗粒,结合散煤-水泥浆胶结体单轴压缩试验和颗粒流模拟软件,研究散煤注浆加固效果,从宏-细观角度揭示散煤水泥浆注浆加固规律。文章构建了散煤-水泥"两介质-三界面"模型;校核了散煤-水泥浆胶结体三界面细观力学参数,分析了颗粒配比和胶结体孔隙率对散煤注浆加固效果的影响规律。研究结果表明："两介质-三界面"模型包括散煤颗粒、水泥颗粒,散煤颗粒之间胶结界面、水泥颗粒之间的胶结界面和散煤与水泥颗粒之间的胶结界面,模型不仅能够模拟常规岩体力学实验,还能够进行胶结参数影响特性研究,适用于散体介质注浆加固效果预判;散煤-水泥浆胶结体单轴压缩强度σc和弹性模量E随着散煤与水泥颗粒配比γ增加先增大后减小,存在最佳配比,散煤含量增加的过程分为初期骨料强化和后期胶结弱化两个阶段;胶结体单轴压缩强度σc和弹性模量E随着孔隙率n增加而加速减小,粒径越小、充填程度越高的注浆材料,加固效果越好。在现场注浆设计施工过程中,根据现场围岩破碎程度,优选粒径小、可注性好的浆液,能够获得较好的注浆加固效果。

Macroscopic and microcosmic consolidation law of loose coal grouting based on the “two media three interfaces” model

In order to predict the effect of cement slurry grouting on reinforcing loose coal seam at Huaibei mining area in China,and provide some reasonable grouting parameters to ensure the stability of loose broken surrounding rock mass,this study revealed the grouting reinforcement law of cement slurry from macro micro perspective.Based on the discrete element theory,the uniaxial compression test on the samples of coal cement and the particle flow simulation software,the “two media three interfaces” cementing model for loose coal and cement was developed.The model not only includes coal particles,cement particles,but also includes interfaces between particles.In the study,the coal cement consolidation microscopic mechanical parameters,the effects of ratio and porosity of the consolidation body were analyzed.The study shows that the “two media three interfaces” model can not only simulate the rock mechanics experiment,but also model the influence of consolidation parameters,and is suitable for predicting the effect of grouting reinforcement.The uniaxial compressive strength (σc) and the elastic modulus (E) of the consolidated body increase first,and then decrease with the increasing proportion of loose coal and cement particles.The process of increasing loose coal content is divided into two stages: the initial stage of aggregate reinforcement and the later stage of cementation weakening.The uniaxial compressive strength (σc) and the elastic modulus (E) of the consolidation body decrease with increasing porosity,and the smaller particle and the higher degree of filling,the better the reinforcement effect.In the process of site grouting design and construction,using cement slurry with small particle size and good injection ability can obtain a better grouting reinforcement effect.