深井高应力大巷煤柱释能改性防冲机理及应用

Mechanism and application of energy release modification of coal pillar in high stress roadway in deep well

针对当前我国深井高应力大巷煤柱频繁发生冲击地压的现状,采用现场调查、理论分析、数值模拟和工程试验等方法,研究了我国大巷煤柱冲击地压发生类型与机理,提出了一种高应力大巷煤柱释能改性防治冲击地压的新方法,基于该方法开展了防冲原理研究、技术体系设计、井下工业试验等一系列研究工作,得到:基于大巷煤柱冲击地压的主导力源类型,结合多起冲击地压典型案例,将我国大巷煤柱冲击地压划分为基础应力叠加型、附加应力诱发型和自身蠕变失稳型3类,分别建立并推导了3类大巷煤柱冲击地压发生机理的力学模型与工程判据,揭示了3类大巷煤柱冲击地压的发生机制。提出一种深井高应力大巷煤柱压裂−注浆协同防治冲击地压的方法,其防冲原理体现在“释能”和“改性”2个方面,井下工业试验发现弹核煤体起裂压力约40 MPa,整体最大压裂宽度达19.5 m,现场监测验证该方法能够降低大巷煤柱能量积聚水平,提高大巷煤柱整体冲击阈值。设计了深井高应力大巷煤柱释能改性防冲成套技术体系,包括孤立煤体冲击危险“评估−检验−校核”方法、弹性核水力压裂增缝释能技术和整体注浆加固改性技术。研发了大巷煤柱弹性核压裂“震动−应力−位移”三场监测设备和PS-Z-A/B型无机双组份速凝整体注浆改性材料。

In view of the frequent occurrence of rockburst in the coal pillars of high-stress roadways in deep underground coal mines in China,the types and mechanisms of rockburst in coal pillars are studied by means of field investigation,theoretical analysis,numerical simulation and engineering test.A new method of preventing rockburst by releasing energy and modifying the coal pillars of high-stress roadways is put forward.Based on the method proposed,a series of research work such as the principle research,technical system design and underground industrial test are carried out.Based on the main force source types of coal pillar rockburst in roadways,combined with many typical cases of rockburst,the coal pillar rockburst in roadways in China is divided into three types:basic stress superposition type,additional stress induced type and self-creep instability type.The mechanical models and engineering criteria of the occurrence mechanism of coal pillar rockburst in roadways are established and deduced respectively,which reveals its occurrence mechanism.In this paper,a method of preventing rockburst by combining fracturing with grouting in high-stress roadway in deep mine is pro-posed.The principle of preventing rockburst is embodied in two aspects:“energy release”and“modification”.The under-ground industrial test shows that the crack initiation pressure of elastic core coal is about 40 MPa,and the overall maximum fracturing width is 19.5 m.The field monitoring proves that the method proposed can reduce the energy accumulation level of roadway coal pillar and increase the overall impact threshold of roadway coal pillar.A complete technical system of coal pillar energy release modification and erosion prevention in high stress roadways of deep underground coal mines is designed,including the“evaluation-inspection-check”method of impact risk of isolated coal body,the energy release technology of elastic nuclear hydraulic fracturing and the whole grouting reinforcement modification technology.The“vibration-stress-displacement”three-field monitoring equipment for the elastic nuclear fracturing of coal pillars in roadways and the PS-Z-A/B type inorganic two-component quick-setting integral grouting modified material have been developed.