摘要
为了研究大口径抽排钻孔套管的稳定性,在总结套管抗挤强度计算方法的基础上,分析了地层流体压力、固管质量、表土层沉降、爆破震动及巷道开挖引起的围岩次生应力等因素对大口径瓦斯抽排钻孔套管的稳定性的影响。结果表明:表土层沉降产生的负摩阻力增加了套管轴向应力,进而减小了套管的抗挤强度;爆破震动产生的应力波的衰减特性与套管距炮心的距离有关,当套管处的径向应力峰值大于套管的动抗挤强度时,套管发生失稳;巷道开挖产生的围岩次生径向应力值一般小于原岩径向应力值,对套管稳定性的影响较小。
In order to study stability of borehole casing pipe of large diameter borehole for gas extraction from coal seams,according to the calculation of strength against collapse of casing pipe,the factors affecting stability of casing pipe including alluvium fluid pressure,quality of pipe fixing,alluvium settlement,vibration by blasting and induced stress in rocks surrounding roadway were analyzed.The results showed that the negative skin friction resistance on casing pipe caused by alluvium settlement increases the axial stress,thus decreases the strength against collapse;the attenuation characteristic of the stress waves induced by blasting is related to the distance between casing pipe and blasting point,and casing pipe will collapse if the dynamic radial stress peak is bigger than dynamic strength against collapse of the pipe;the radial stress induced by excavation in rocks surrounding roadway is less than initial radial stress,its influence on pipe stability can be neglected.
出处
《安徽理工大学学报(自然科学版)》
CAS
2011年第1期41-44,50,共5页
Journal of Anhui University of Science and Technology:Natural Science
关键词
煤矿安全
瓦斯抽排
钻孔套管
mine safety
gas extraction
borehole casing pipe