全尾砂胶结膏体固化过程热-水-力-化多场性能响应机制及协同表征

Paste backfill technology is one of key solutions to establish green mines. However, the difficulty confronting us in monitoring and characterization of curing paste materials needs to be solved urgently, provided that solidification process of paste in stopes has come into the era of black-box curing operation. Firstly, paste materials at different ratio of cement versus tailings or mass fraction is prepared. Several sets of samples are cured successively for 28 d in a homemade device, which could undertake curing and monitoring simultaneously. In this process, temperature (T), volumetric water content (H), suction (M) and electrical conductivity (C) are monitored and recorded. Then the response mechanism of coupling performance for curing paste materials in the multiple effect of thermo, hydro, mechanical and chemistry is verified, considering different ratio of cement versus tailings and mass fraction. Furthermore, the internal cause of hydration and other performances under varying mixture ratio is analyzed and a correlation mechanism of paste performances in multi-field is established. After that, the sensibility and contribution of each term of multi-field for curing paste is analyzed. A hierarchical coupling characterization method considering thermo, hydro, mechanical and chemistry is established. Then a method monitoring multi-field performances of paste in stopes is proposed. This paper scientifically clarifies interaction of each term in multi field for curing paste, which provides a reference for monitoring and warning operations for curing paste in stopes.

膏体充填技术是绿色矿山建设的重要举措之一，但膏体料充填到空区后即进入“黑箱”养护时代，其固化过程难以监测和表征，是膏体充填亟待解决的技术难题。首先，制备不同灰砂比和质量浓度的膏体料，采用自制多场性能同步监测装置，分别对各膏体固化过程中温度（热）、体积含水率（水）、基质吸力（力）和电导率（化）进行连续监测28天，探明膏体固化过程中热、水、力、化多场性能随不同灰砂比和质量浓度的响应规律。其次，分析不同配比影响下膏体水化机理和各性能演化过程发生内因，构建膏体热-水-力-化多场性能同时演绎关联机制。再次，对膏体固化过程多场性能响应敏感性和贡献进行分析，建立具有层级的膏体固化过程热-水-力-化“四位一体”协同表征方法。最后，建立传统终端表征强度与固化过程多场性能互馈机制，提出采场膏体多场性能监测方法。本项目将科学诠释膏体固化过程中多场性能交互作用这一复杂过程，为采场膏体固化过程监测-预警提供技术原型。

传统的膏体特性研究中，评价膏体性能最常用的方法就是对膏体试块进行单轴抗压强度测试，但单轴抗压强度只能表征膏体的终端强度，不能认清膏体内部多场性能之间的耦合作用，膏体固化过程多场性能监测和表征对充填设计至关重要。项目以全尾砂胶结膏体为研究对象，将宏观-微观-细观相结合，采用室内实验、理论分析和回归分析，研究膏体固化过程中多场性能演化规律以及协同表征机制：.（1）研发了膏体固化过程多场性能监测装置。该装置可对膏体料固化过程中温度、体积含水率、基质吸力、电导率进行同步连续监测，为项目顺利开展提供了硬件保障。.（2）开展了不同配比条件下膏体固化过程多场性能监测实验，探明了膏体固化过程中热、水、力、化多场性能随不同灰砂比和质量浓度变化的响应规律及影响机理。结果表明，膏体灰砂比和质量浓度对固化过程多场性能的影响有相同规律；相同条件下，膏体质量浓度越高，体积含水率越低、水化反应速率越快，相应的基质吸力和强度越高。.（3）开展了膏体固化过程多场性能关联性研究，建立了不同灰砂比和质量浓度膏体热-水-力-化学性能关联机制，并将膏体固化过程分为了自适应阶段、快速发展阶段和平稳发展阶段。.（4）分析了各场性能与膏体强度之间关系，建立了不同灰砂比和质量浓度条件下，基于固化性能的膏体强度协同表征方法。结果表明，膏体的基质吸力、体积含水率、电导率都与单轴抗压强度呈多元线性函数关系。.（5）提出了采场膏体固化过程多场性能监测方法。研究成果将为采场膏体固化过程监测-预警提供技术原型，为金属矿充填开采提供理论指导。