真三轴条件下生物质与煤混燃灰地聚物充填体渐进破坏机制研究

生物质与煤混燃灰具有活性，但作为胶凝材料制备充填体还有待研究，充填体在真三轴条件下的渐进破坏机制尚不清楚。项目采用碱激发和机械活化激发生物质与煤混燃灰活性并掺入少量矿渣制备地聚物胶凝材料，以破碎的煤矸石为骨料制成膏体充填材料，采用响应面法与满意度函数法确定充填体的最优配合比，测试胶凝材料和充填体的微观结构及化学成分，分析强度形成机理。采用自制的可视化真三轴试验机与白光数字散斑方法，研究不同中间主应力、不同加载速率和应力-应变混合加载路径下充填体的渐进破坏规律，分析充填体的变形局部化启动与演化特征、泊松比和能量释放演化特征，根据损伤能释放率建立充填体的损伤准则与损伤演化准则，通过算子分离算法的弹性预测、塑性修正和损伤修正建立损伤本构模型并进行二次开发，揭示真三轴条件下生物质与煤混燃灰地聚物充填体的渐进破坏机制。项目研发新型膏体充填材料并分析破坏机制，对膏体充填开采的研究与应用具有推动作用。

Co-combustion of biomass and coal ash is a substance with pozzolanic activity, but the preparation of binder for cemented paste backfill (CPB) requires further study, and the progressive failure mechanism of CPB under true triaxial conditions is unclear. In this project, the co-combustion of biomass and coal ash with a small amount of slag as the geopolymer binder is mechanically activated and activated by alkali, and crushed coal gangue is used as the aggregates for preparing the CPB. The response surface method and desirability function method will be used to determine the optimal proportion of CPB. The microstructure and chemical composition of the binder and the CPB will be tested to analyze the strength formation mechanism. A visual true triaxial testing machine and white light digital speckle correlation method will be used to study the progressive failure of CPB under different intermediate principal stresses, different loading rates, and mixed stress-strain loading paths. The localized deformation initiation and evolution characteristics, Poisson's ratio and energy release evolution of CPB will be analyzed. The damage criterion and damage evolution criterion of the CPB will be established according to the damage energy release rate. The damage constitutive model will be established through elastic predictions, plasticity corrections and the damage correction of the operator splitting technique, and secondary development will be carried out. The progressive failure mechanism of the co-combustion of biomass and coal ash geopolymer CPB under true triaxial conditions will be revealed. In this project, a new type of CPB will be developed, and the failure mechanism will be analyzed, which will promote the study and application of paste backfill mining.