锚固预紧力和预留尺寸对煤柱承载特性影响分析

Analysis on influence of anchorage preload and reserved size on bearing capacity of coal pillar

锚固预紧力和煤柱留设尺寸对煤柱稳定性有着重要的影响。研制了可变预紧力作用下不同尺度破碎煤岩压缩承载实验装置,通过对两端不同预紧力作用下破碎煤岩单轴压缩实验,分析了不同预紧力、不同煤岩尺寸条件下的承载特性。结果表明:初始侧压越大相同尺度煤样强度越高;煤样强度与试件尺度较好符合二次多项式函数;初始侧压为1 kN,煤柱尺度为21 cm时,煤柱稳定性效果最佳。煤柱尺寸相同情况下,支护强度越大,煤岩承载能力越强。在提高一定的支护预紧力时,可以适当减小煤柱宽度以提高煤柱的整体稳定性。研究成果为煤柱留设与围岩控制提供了实验依据。

The anchorage preload and size of coal pillar have an important influence on stability of coal pillar.An experimental device for compression and bearing of fractured coal and rock under action of variable preload was developed.Through the uniaxial compression experiment of fractured coal and rock under action of different preload at both ends,the bearing characteristics of different preload and different coal and rock size were analyzed.The results showed that the larger the initial lateral pressure was,the higher the strength of coal sample with the same scale was;the better the coal sample strength and specimen scale were in accordance with quadratic polynomial function;when the initial lateral pressure was 1 kN and the coal pillar scale was 21 cm,the stability effect of coal pillar was the best.Under the same size of coal pillar,the larger the supporting strength was,the stronger bearing capacity of coal rock was.In order to improve the overall stability of coal pillar,the width of coal pillar can be reduced properly when the pre-tightening force of support was increased.The research results provided experimental basis for coal pillar reservation and surrounding rock control.