基于FLAC^(3D)数值模拟的钻孔破坏特征分析  

Failure characteristics of borehole based on FLAC^(3D) numerical simulation

作　　者：雷腾飞 李博涛 LEI Tengfei;LI Botao(Shaanxi Huangling No.2 Coal Mine Co.,Ltd.,Yan’an 727300,China)

机构地区：[1]陕西黄陵二号煤矿有限公司,陕西延安727300

出　　处：《陕西煤炭》2024年第4期23-28,共6页Shaanxi Coal

摘　　要：随着煤矿开采逐渐向深部发展,瓦斯超限事故危害增大,为保障煤矿生产安全,煤层瓦斯钻孔预抽技术是目前较有效的技术之一,钻孔质量对于抽采效果有着重要影响作用。采用FLAC^(3D)数值模拟软件,研究煤体在不同因素影响下钻孔破坏特征,分析煤体纵向位移的变化规律。结果表明,随着钻孔直径的增大,钻孔顶部纵向位移增长1.10%,钻孔腰侧变化较小,钻孔底部纵向位移降低17.05%;随着稳压压力的增大,钻孔顶点纵向位移增大42.48%,钻孔腰侧纵向位移增大38.89%,钻孔底部纵向位移增大38.39%;随着加载速率的增大,钻孔顶点纵向位移最大为0.053 mm,钻孔腰侧纵向位移最大为0.023 mm,钻孔底部纵向位移最大为0.005 mm。钻孔直径、稳压压力及加载速率与纵向位移呈负相关关系。通过对煤体钻孔试件在应力应变曲线中不同阶段进行机理分析,阐明了钻孔失稳全过程的变化情况,为保障煤层瓦斯钻孔安全预抽提供了理论依据。With the gradual development of coal mining to the deep,the harm of gas over-limit accidents increases.In order to ensure the safety of coal mine production,coal seam gas drilling pre-extraction technology is one of the most effective technologies.Drilling quality had an important influence on the extraction effect.Based on FLAC^(3D) numerical simulation software,the characteristics of borehole failure under the influence of different factors were studied.The variation law of coal longitudinal displacement was analyzed.The results show that with the increase of borehole diameter,the longitudinal displacement at the top of the borehole increased by 1.10%.The change of the waist side of the borehole was small.The longitudinal displacement at the bottom of the borehole was reduced by 17.05%.With the increase of the pressure,the longitudinal displacement of the borehole vertex increased by 42.48%.The longitudinal displacement of the waist side of the borehole increased by 38.89%.The longitudinal displacement at the bottom of the borehole increased by 38.39%.With the increase of loading rate,the maximum longitudinal displacement of drilling vertex was 0.053 mm.The maximum longitudinal displacement of the waist side of the borehole was 0.023 mm.The maximum longitudinal displacement at the bottom of the borehole was 0.005 mm.The borehole diameter,stabilizing pressure and loading rate were negatively correlated with the longitudinal displacement.Through the mechanism analysis of different stages on the stress-strain curve of coal drilling specimens,the whole process of borehole instability was clarified.The study provides a theoretical basis for ensuring the safe pre-extraction of coal seam gas.

关 键 词：瓦斯抽采 钻孔预抽 钻孔破坏特征 稳压压力 加载速率 

分 类 号：TD712.6[矿业工程—矿井通风与安全]