CCTEG Coal Mining Research Institute
State Key Laboratory of Coal Mining and Clean Utilization
School of Energy and Mining Engineering, China University of Mining & Technology-Beijing

煤层加载刚度及峰后承载刚度是影响冲击地压发生的重要因素,为了系统研究基于局部矿井刚度理论的冲击地压发生机理及煤柱冲击破坏规律,开发了冲击地压实验室试验装置。试验装置主要由静力加载系统、储能系统、变刚度加载系统、开挖系统和多源信息监测系统 5 部分组成。该试验系统的主要创新性如下:① 加载系统中增加开挖装置,可在保压状态下通过开挖诱发试样产生应力集中及局部矿井刚度的降低,当试样受力达到其承载强度、局部系统刚度低于试样峰后刚度时将发生冲击破坏;② 加载系统中设置了气囊式蓄能器−油缸的复合液压弹簧储能装置,可在静力加载过程中完成能量的储存;③ 设置了一种变刚度加载装置,系统可通过蓄能器初始气囊压力的调整实现不同加载刚度的设置;④ 试验装置可对试样从加载—稳压—开挖—冲击全过程进行实验室再现,使得冲击地压发生全过程煤柱应变监测以及冲击过程观测成为可能。通过对高强度混凝土试块和强冲击倾向性煤样进行初步实验室试验,验证了该模拟设备的准确性和可靠性,初步试验结果表明:低刚度加载条件下通过开挖底部试样可有效诱发煤柱发生冲击破坏,煤柱破坏由低刚度侧向高刚度侧扩展贯通,破坏后的残留煤柱呈现出“两侧宽中心窄”的哑铃状态。冲击破坏后的煤柱中心被一条横向锯齿裂纹贯穿,致使煤柱承载能力大幅度降低。该试验系统从加载储能及刚度角度出发,可实验室再现煤体在加载—稳压—开挖—冲击破坏的冲击地压发生全过程,为煤矿冲击地压发生机理研究提供试验平台。

The loading mine stiffness and the post-peak stiffness of a coal pillar are important factors affecting the occurrence of coal bursts. In order to systematically study the mechanism of coal bursts and pillar bursts based on local minestiffness theory, a laboratory-scale coal burst experiment system has been developed. The system is mainly composed ofstatic loading system, energy storage system, variable stiffness loading system, excavation system and multi-source information monitoring system. The main innovations of the test system are as follows: ① An excavation device is added tothe loading system, which can induce the stress concentration of the specimen and the reduction of local mine stiffnessthrough excavation in the pressure-holding state. Coal bursts will occur when the specimen is stressed to its bearing capacity and the local system stiffness is lower than the post-peak stiffness of the specimen. ② The loading system is equippedwith an energy storage device of oil cylinder airbag accumulator, which can store energy during loading. ③ A variablestiffness loading device is set up to adjust different loading stiffnesses by adjusting the initial airbag pressure of airbag accumulator. ④ The experiment system can reproduce the whole process of specimen from loading-stabilization-excavationburst in laboratory, which makes it possible to monitor the strain of coal pillar during the whole process of coal bursts andobserve the burst process. The accuracy and reliability of the simulation equipment are verified by preliminary laboratorytests on high-strength concrete blocks and realistic coal samples. The test results show that under the condition of low stiffness loading, the unstable failure of coal pillars can be effectively induced by excavating bottom samples, and the failureposition extends from the low stiffness side to the high stiffness side. The damaged central residual coal pillar is dumbbellshaped under the action of top and bottom plate friction, and is cut off at the center by a transverse sawtooth crack penetrating the sample, resulting in a significant reduction in the bearing capacity of the coal pillar. The development of the experiment system can reproduce the whole process of coal bursts from loading, pressure stabilization, excavation and unstable failure in the laboratory from the perspective of local mine stiffness, and can provide an experimental basis for themechanism of coal bursts in coal mines.

国家自然科学基金资助项目(52274085,52074154);天地开采设计事业部科技创新基金资助项目(TDKC-2022-QN-01)

高富强,原贵阳,娄金福,等. 基于局部矿井刚度理论的冲击地压试验装置研制及应用[J]. 煤炭学报,2023,48(5):1985−1995.

GAO Fuqiang,YUAN Guiyang,LOU Jinfu,et al. Development and application of coal burst experiment sys-tem based on local mine stiffness theory[J]. Journal of China Coal Society,2023,48(5):1985−1995.