基于分布式感测的采动覆岩变形破坏机理及离层演化过程研究

Coal seam mining often causes land subsidence and collapse which poses a threat to the safety of ground structures and geological environment. At present, the study on mechanism of uneven settlement and collapse of the coal seam, especially the deformation and failure of overlying strata is limited. This project aims to detect the overburden deformation caused by mining. Similar material model test, field test, theoretical analysis and numerical simulation are used to study the failure mechanism of overlying rock and evolution of abscission layer caused by coal seam mining. Based on the distributed optical fiber sensing technology, the project puts forward a distributed sensing method for monitoring the deformation and failure of overburden rock. Special sensing optical cables for monitoring overburden rock deformation are developed. Based on sensing optical cable pull-out tests, the coupling performance of cable and rock-soil mass is analyzed and the mechanical transfer model of the cable and rock-soil mass interface is established. According to the theory of cantilever beam and key stratum, the safety evaluation system of the deformation and failure zone of mining overburden rock is established. This project will reveal the mechanism of overburden deformation-failure effect on the surface environment, and to achieve distributed sensing and warning forecast from micro deformation to macro disaster. Moreover, it provides the basis and technical support for mining safety assessment and development of coal mining control standards.

煤层开采引起地面沉降和塌陷，对地面构筑物安全和地质环境产生影响。当前煤层开采导致地面不均匀沉降和塌陷的机理，尤其是覆岩变形破坏机理及离层演化过程研究还不够深入。本项目以矿山开采引起的上覆岩层变形破坏监测为对象，采用相似材料物理模型试验、现场测试、数值模拟和理论分析相结合的方法，研究采动覆岩变形破坏机理及离层演化过程。基于分布式光纤感测技术，提出采动覆岩变形破坏的分布式感测方法；研发覆岩变形监测用特种感测光缆；通过光缆拉拔耦合性试验，分析感测光缆与岩土体的耦合性能，建立感测光缆-岩土界面拉拔力学传递模型；根据悬臂梁和关键层理论，建立采动覆岩变形破坏影响区的安全性评估体系。通过本项目的研究，将从本质上揭示覆岩变形破坏对地表环境影响的机理，实现从细观变形到宏观灾变的分布式感测和预警预报，为开采巷道和地表环境的安全评估及煤层开采控制标准的制定提供理论依据和技术支撑。

本项目紧紧围绕“基于分布式感测的采动覆岩变形破坏机理及离层演化过程研究”这一中心课题，主要以矿山开采引起的上覆岩层变形破坏为监测对象，开展了覆岩变形破坏机理研究；采用相似材料物理模型试验、现场测试、数值模拟和理论分析相结合的方法，深入探讨了煤层开采过程中上覆岩体的变形破坏与离层演化特征，为采动覆岩变形破坏机理和离层演化评价提供了新的思路和方法。项目取得了一批创新成果：（1）研发了适用于覆岩变形监测用的特种感测光缆并对其性能进行了标定，同时对光缆的适用条件进行了分类；（2）掌握了感测光缆与岩土体耦合性作用过程，建立了光缆-岩土体界面应变传递力学模型，并用该模型对光缆与岩土体的耦合性能进行分析评价；（3）建立了采动覆岩变形监测系统框架，优化了监测数据采集与传输，实现了数据自动识别和异常处理等功能；（4）提出并应用了煤层采动覆岩变形分布式光纤监测技术，获得了淮北地区煤层开采过程中上覆岩体变形分布规律和离层演化过程；（5）提出了采动覆岩变形破坏致灾潜力评价方法，并对“两带”高度进行了判定。本项目的研究实现了从细观变形到宏观灾变的分布式感测和预警预报，为开采巷道和地表环境的安全评估及煤层开采控制标准的制定提供了参考依据和技术支撑，相关研究成果具有良好的应用推广价值。