煤矿充填体弱化采动影响的“移动切眼”理论研究

Backfill mining is a green mining method which can control the mining pressure and surface subsidence, and realize the coordinated development of resource exploitation and environmental protection. There is a significant difference in ground pressure behavior and strata control between the backfill and traditional caving method. This project is aimed at key scientific problems including how to scientifically express the state of weakened mining influence induced by backfill body (shorted as Weakening Effect), what’s the feature difference of strata pressure in backfill stope and Whether it is reasonable to put forward a new “moving set-up room” theory. Through theoretical analysis and simulation method to research the mechanism of weakened influence of mining activities induced by backfill body. At first, based on the analysis of the application of typical backfill face, get the basic characteristics of the Weakening Effect. Then, using Pro/E and ABAQUS to simulate the dynamic circulation process of “coal cutting, support moving and supporting-backfilling”, real-time monitor some typical data, such as the stress concentration coefficient, to study the strata behavior of backfill stope under multi factor. And then according to the similarly weak mining influence features of "set-up room" in traditional caving mining stope, put forward an “moving set-up room” theory to intuitively express this weaken effect in backfill mining induced by backfill body, and show basic dynamic law of the stress field and displacement field in backfill stope and get the critical condition from the backfill rate controlling and so on. Finally, based on the newly “moving set-up room” theory, to guide the design of mine pressure control in backfill mining stope.

充填采煤技术是通过充填体控制覆岩运动，实现资源开采与环境保护协调发展的绿色开采方法，其充填采场矿压显现与岩层控制较垮落法有显著区别。针对充填体对采动影响弱化效应的科学界定、充填采场矿压显现特征差异及“移动切眼”理论构建等关键科学问题，采用理论分析、仿真模拟等相结合的研究方法研究充填体弱化采动影响机制。通过总结典型充填工作面应用情况，分析充填体弱化采动影响的基本特征；联合采用Pro/E、ABAQUS等软件进行“采煤-移架-充填”循环工艺的仿真模拟，并实时监测应力集中系数等反馈采动影响指标的数据，研究多因素耦合作用下充填采场的矿压显现规律；结合“切眼”对采动影响微弱的特征分析，提出采用“移动切眼”理论学说直观表达充填体对采动影响的弱化效应，进而表征充填开采应力场与位移场动态演化的基本规律；并从充实率控制等方面给定充填采场形成“移动切眼”的临界条件；最终基于“移动切眼”理论指导充填采场矿压设计。

固体充填采煤技术作为绿色开采技术的典型代表，其在“三下”压煤解放、固废处理、地表变形控制等方面具有显著的技术优势，国家鼓励矿井采用充填采煤技术回收煤炭资源，充填采场采动影响状态与程度是充填开采岩层控制的关键，充填体对采动影响有明显的弱化效应，但如何定性定量表征充填体弱化采动影响的状态与程度尚需深入研究。.基于此本项目通过采用理论分析、数值模拟和现场试验等研究手段，实测分析了充填体对采动影响的弱化效应、构建了充填开采采场“移动切眼”理论学说，分析了“移动切眼”理论的临界条件及工程案例设计，取得以下研究成果：（1）总结了充填采煤工程应用情况，分析得到典型充填工作面充填体弱化采动影响的基本特征，具体是最大动载系数1.19，充填体应力稳定在2.78Mpa，充填体最大变形值为211.5mm，充实率稳定在81.3%；并采用煤壁峰值应力、应力集中系数和顶板下沉量三个指标表征了充填采场矿压显现弱化规律，充填（充实率90%）相比垮落法矿压显现显著弱化，表现为煤壁峰值应力减弱48.5%，应力集中系数仅为二分之一，顶板最大下沉量仅为垮落法开采的10.2%。（2）进一步分析了充实率、充垮比、煤柱宽度等因素影响充填采场应力和位移弱化规律：充实率影响弱化效应体现为充实率越大，煤壁支承峰值应力降低越明显；充垮比影响弱化效应体现为充垮比越大，弱化矿压显现效应越明显；增加煤柱宽度有益于降低采场矿压。分析了工作面开切眼破坏原岩的量化特征，提出了提出充填采场“移动切眼”理论学说：充填采煤工作面对采动的影响等效于一个缓缓前行的开切眼对覆岩采动的影响。（3）给出了充填开采采场形成“移动切眼”效应的临界条件解算方法，设计了某矿形成“移动切眼”效应的临界充实率为80%。研究成果深化了充填采煤矿压控制理论，为充填开采矿压控制设计提供了理论依据。.依托项目发表学术论文7篇（SCI 3篇、EI4篇）、获授权发明专利6件、获科研奖励3项、制订国家标准1项、科技成果鉴定（国际领先水平）1项。