顾及结构关键层控制的条带充填开采地表沉陷动态预计方法研究

The surface dynamic subsidence prediction is the core problem in the application of backfill-strip mining to mine the difficult coal seam under buildings and water, but the traditional surface subsidence dynamic prediction method has not taken into account the rheological characteristics of the composite support pillar and key stratum control in backfill-strip mining, which can affect its prediction accuracy. The study object of the project is to study the surface subsidence dynamic prediction method for backfill-strip mining and its main line is “the rheological characteristics of the composite support pillar – the dynamic mechanical model of the key stratum – the combined prediction method of surface dynamic subsidence”. The rheological characteristics of the composite support pillar and the dynamic subsidence characteristics of the key stratum and surface will be studied with mechanical testing, similar materials simulation, numerical simulation and field measurement, then the dynamic deformation mechanics model of the key stratum supported by the composite support pillar. Based on the idea of multi-medium coupling modeling, a combined prediction method of surface dynamic subsidence for backfill-strip mining considering the control of the key stratum will be established, and the parameters selection of the prediction method would be proposed. The research results of this project provide the theoretic reference and technical support for the engineering design of backfill-strip mining, improve the theoretical base framework of the green mining technology as well, which will be of great theoretical value and applicable significance.

地表沉陷动态预计问题是条带充填开采应用于复杂难采煤层（如建筑物下、水体下）时面临的核心问题，但传统地表沉陷动态预计方法未顾及条带充填开采中复合支撑体流变特性和结构关键层控制作用等问题，势必会影响其预计精度。本项目将条带充填开采地表沉陷动态预计方法作为研究对象，以“复合支撑体流变特性-结构关键层动态力学模型-地表动态耦合预计方法”为研究主线，采用力学实验、相似材料模拟、数值模拟和现场实测相结合的方法，通过对复合支撑体流变特性、结构关键层及地表动态变形特征等问题的研究，优选出适合复合支撑体动态变形特征的流变模型，建立复合支撑体动态支撑下的结构关键层移动变形时空力学模型；在此基础上，结合多介质耦合建模方法，提出顾及条带充填开采结构关键层控制的地表沉陷动态耦合预计模型以及参数选取方法。研究成果对指导条带充填开采设计、完善绿色开采基础理论框架具有重要的理论与应用价值。

如何精确的预计条带充填开采地表沉陷情况，对于合理地布置条带充填工作面、减少地表建（构）筑物损害、改善矿区生态环境等有着重要的现实意义。本项目综合采用了力学实验、相似材料模拟、数值模拟和现场实测相结合的研究方法，首先设计了复合支撑体压缩实验装置，通过力学实验获取了复合支撑体压缩变形过程及压缩变形-时间的曲线，总结了复合支撑体动态压缩特征，建立了复合支撑体鲍埃丁-汤姆逊蠕变模型；再通过相似材料模拟和数值模拟，分析了条带充填开采岩层动态下沉特征以及下沉速度时间尺度效应，建立不同状态下的岩体运动速度与时间之间的函数模型；在此基础上，揭示了复合支撑体-结构岩层协同控制机理；最后，综合考虑在复合支撑体压缩特性影响下的结构关键层时空变形过程、力学模型假设、上覆岩层载荷假设、边界条件以及模型解法等问题，建立结构关键层动态力学模型，并与上覆岩层空间层状力学模型相耦合，最终建立条带充填开采岩层及地表移动变形预计模型。研究成果对指导条带充填开采设计、完善绿色开采基础理论框架具有重要的理论与应用价值。