采动压力作用下深部蠕变煤柱突变失稳致冲机理

A coal pillar, which was in creep state for a long time, would likely to collapse and then even trigger rockburst under the influence of the front abutment pressure, and will cause serious threaten to safety production of deep coalmine. In this project, the theoretical analysis, laboratory test, numerical simulation and field test are comprehensive used to study on those reative research: ①Mechanical response and fracture evolution characteristics of high-stress creeped coal was investigated during loading process, and the stress threshold indicating that the high-stress creeped coal is susceptible to loading failure, is obtained, and then damage constitution relation was establish by defining damage variables using fractal dimension of crack propagation; ②the progressive failure and aging evolution of coal pillar under different front abutment pressure was studied, and the effect of creep pillar stress and front abutment pressure on the coal pillar failure was revealed, and then leading factor that the effect the coal pillar instability was achieved; ③On the basis of analysis on the mechanical process of coal pillar instability in deep coal mining under front abutment pressure, nonlinear dynamic structural model for coal pillar instability was established and catastrophe mechanics criterion that characterized by creep pillar stress and front abutment pressure was obtain, and then the main force source that control coal pillar instability in under different stress conditions was identificated. The results of this project will provide theoretical basis and guidance for safe and efficient production of deep coalmine.

长期处于蠕变状态的深井煤柱在采动应力影响下易失稳破坏，甚至引发冲击地压动力灾害，给矿井安全生产造成严重威胁。本项目拟采用室内试验、理论分析、数值模拟和现场测试等综合研究方法，研究如下创新性内容：①探讨高应力蠕变煤体加载力学响应及破裂演化特征，获得不同蠕变煤体加载破坏所需的阈值应力，以裂纹分形维数为损伤变量构建高应力煤体损伤本构关系；②研究不同采动应力环境下深部蠕变煤柱渐进破坏及时效演化特征，揭示煤柱蠕变应力、采动应力对煤柱失稳的影响规律，获得深部蠕变煤柱失稳的主导因素；③分析采动影响下深部蠕变煤柱失稳灾变的力学过程，建立采动应力作用下深部蠕变煤柱突变失稳致冲非线性动力学结构模型，提出以煤柱蠕变应力、采动应力为特征的灾变力学判据，获得不同应力条件下蠕变煤柱灾变的主控力源，阐明采动应力作用下深部蠕变煤柱失稳灾变机理。本项目研究成果将为深部矿井的安全高效开采提供理论依据与指导。

井下煤柱类型多样，包括区段煤柱、边界煤柱和采区煤柱等，其中采区煤柱（宽度20m至40m不等）是井下煤柱的重要组成部分，肩负着保障上（下）采区大巷稳定的重要任务，一旦破坏失稳严重影响整个区域通风、运输以及行人安全。本项目采用试验研究、理论分析、数值模拟和现场测试相结合的方法，研究如下创新性内容：.（1）利用MTS伺服压力试验机、高精度声发射仪、霍普金森压杆等实验设备，开展不同条件下高应力煤体常规三轴、蠕变-动载冲击力学试验，获得不同加载条件下应力-应变演化规律，洞察煤体微裂纹的形成、发展、贯穿形成裂纹群的演化力学机制及特征，为分析采动应力下蠕变煤柱破裂损伤提供依据。.（2）在掌握深井煤体变形破坏的基础上，基于损伤力学，建立了考虑损伤的Burgers蠕变模型，推导相应的蠕变本构关系，基于该本构关系，利用FLAC3D开展了动载冲击下深井煤柱稳定性分析，并进行现场验证。.（3）在掌握深井煤柱失稳破坏影响因素的基础上，基于弹性薄板理论建立了冲击动载下高应力煤柱-顶板非线性失稳结构力学模型，揭示动载作用下深井煤柱的突变失稳机理，推导了煤柱稳定性判别式，并通过现场实践验证。.（4）基于深井煤柱稳定性判别关系，建立了深井煤柱稳定性控制体系，并通过现场实践验证。.本项目已获得授权国家发明专利6项，国外发明专利1项，发表相关学术论文7篇，其中SCI收录2篇、中文EI检索4篇，北大中文核心论文1篇，相关研究成果经中国煤炭工业协会组织的专家鉴定，认为“项目成果达到国际领先水平”，具有很强的国际竞争力和示范性，有助于我国煤矿安全生产的科技进步。