Analysis of the effects of weak floor strata on longwall face stability using finite element modeling

• 来源期刊: 煤炭学报（英文版）
• 学科: 工学
• 年，卷（期）: 2001,（1）
• 页码范围: 1-8
• 页数: 8页
• 分类号: TD82
• 语种: 英文

摘要

Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short period of time. It is now a serious challenge to cope with ground control problems such as roof falls, face and floor failure, and excessive shield loading as fast as possible to minimize production and monetary losses. In Illinois Coal Mines, the existence of week floor strata blow the coal seam may pose additional problems related to floor heaving,shield base punching, and associated roof and face falls. In this study, the effects of week floor on longwall grouJd control are analyzed using two-dimensional finite element models. A two-leg 635.6 ton (700-short-ton) yielding capacity shield is included in the models to evaluate the effects of different thicknees and material properties of the weak floor. The study indicates that the thickness and material properties of weak floor have significant effects on shield loading, the distribution and intensity of front abutment stress, failure zones in the surrounding strata, roof-to-floor convergence, and floor punching by the shield base.