深井多场耦合作用下充填体强度演化规律及调控机制

Under the coupling interaction of stress field, seepage field and temperature field, the strength of the filling body is much larger than that of the indoor experiment under the conventional maintenance condition in practices, which will cause considerable design error. This project will break through the traditional curing method of temperature and humidity control, and focus on the study of the strength evolution law and regulation mechanism of the filling body under the multi-field coupling effect. First of all, the evolution of filling body strength under multi-coupled maintenance effect will be analyzed through the way of performing relative experiment. Secondly, based on the CT scanning technology, the study will be done by analyzing the quantitatively microscopic structure characteristic of filling body, and building comprehensive characterization system of mesostructure and macro mechanics parameters to reveal the mesomechanism of the evolution of filling body under multi-coupled effect. Thirdly, the study of analyzing the stress-strain curve and destruction form, the buckling failure criterion of filling body under multi-fields in deep will be proposed, and mechanic constitutive model of the filling body will be built. At last, the refactoring and constitutive model of CT will be imported, comparing to the different characteristics of filling body in multi-factors fields, and then there will be a report to analyze evolutional factors of strength and stability factors, propose the regulation of filling body adapting to deep mining environment. This project will erect the prototype of process control technology and the strength evolution and development of the filling body under the condition of multi-field and multi-factors in deep mining, and provide the theoretical and technical guidance for deep metal filling mining.

在应力场—渗流场—温度场耦合作用下，采场充填体强度远大于常规养护条件下室内实验值，从而产生较大设计误差。本项目突破传统温度+湿度控制养护方法，开展多场多因素交互作用下的充填体强度演化规律与调控机制研究。首先，开展多场耦合养护试验，分析多场耦合作用下充填体强度演化规律；其次，基于CT技术，定量分析充填体细观结构特征，建立细观结构与宏观力学参数综合表征体系，揭示多场耦合作用下充填强度演化的细观机理；第三，分析充填体应力应变曲线与破坏形式，提出多场环境下充填体失稳破坏判据，建立多场耦合条件下充填体力学本构模型；最后，将CT重构模型导入COMSOL Multiphysics软件中，对比多场条件下充填体强度特征，分析强度演化影响因素和稳定因子，提出与深井采场环境相应的充填体强度调控措施。本项目将形成深井多场多因素耦合条件下充填体强度演化规律及过程调控技术原型，为深井金属矿充填开采提供理论和技术指导。

传统的膏体充填体强度设计中，材料配合比确定均是在室内标准恒温恒湿条件下进行，这与膏体充填体的原位养护环境存在较大差异，现场取样得到的充填体强度明显高于室内试样的强度（即设计强度）。项目以深井膏体充填体为研究对象，将宏观-微观-细观相结合，采用室内试验、理论分析和数值模拟，研究深井多场耦合作用下膏体充填体的强度演化规律及调控机制：.（1）研发了多场耦合养护环境下膏体充填体养护实验装置。.（2）开展了多场耦合养护环境下膏体充填体的力学性能测试实验，探明了多场耦合养护环境下膏体充填体物理力学性能的演化规律，构建了多场耦合养护环境下膏体充填体两段式损伤本构模型。结果表明，膏体充填体的强度随养护压力的增加呈一元二次函数的增加，随养护温度的增加呈S型函数增加，随养护时间呈现对数函数的增加趋势，且膏体充填体强度的增加速率随养护压力和养护温度的增加呈现减小的趋势。.（3）研究了多场耦合养护环境下膏体充填体颗粒接触特征、力链分布和裂纹分布特征演化规律，结果表明，随着养护压力与养护温度的增加，膏体充填体内部颗粒接触完整性破坏更小，力链分布更加均匀，裂纹数量逐渐减小。.（4）探明了多场耦合养护环境下膏体充填体内部热-水-力-化多场性能演化规律。结果表明，养护压力与养护温度越高，膏体充填体的体积含水率越小。电导率随养护时间的增加呈现出先增加后减小的趋势。.（5）研究了多场耦合养护环境下膏体充填体的物相组成、微观形貌和孔隙结构演化规律。养护压力和养护温度的增加促进膏体充填体的水化反应速度加快，产生了更多水化产物，使膏体充填体的孔隙结构更加密实，促使膏体充填体强度增加。.（6）发展了多场耦合养护环境下膏体充填体配合比优化设计新方法，提出了多场耦合养护环境下膏体充填体配合比优化设计工程措施及建议。研究成果将形成深井多场多因素耦合条件下充填体强度演化规律及过程调控技术原型，为深井金属矿充填开采提供理论和技术指导。