煤层开挖过程中底板突水的弹塑性有限元模拟及初步分析

本文在总结分析我国华北一些煤矿底板突水的现象和普遍规律的基础上,运用弹塑性有限元方法模拟了河南焦作九里山煤矿某采区实际开采过程中完整底板内注水区(对应于塑性变形的岩石)范围和某深度处岩石的变形以及它们的变化,模拟计算结果与实测资料基本吻合,初步分析还可得出一些有关采动过程中底板突水规律的认识。

The Elasto-Plastic Modelling and Preliminary Analysis of Water Inflow Through Basement During Coal Excavation Using Finite Element Method

Based on the summary and analyses of water inflow through basements in some coal fields in North China, the advancing process of excavation on a complete basement is modelled using elasto-plastic finite element method. The elastic and plastic parameters of the rocks in coal bearing and surrounding strata are gained or computed from those of rock mechanical experiments, and the excavating and filling processes are reflected in the modelling.Comparing with the in-situ measurements in a service roadway under an excavated coal layer in Jiaozuo, Henan province, the modelling computation results are analy- zed. The computed distribution of plastical areas is in relatively good accordance with that of water injected areas, these areas are considered here as water inflowable regions of rocks and water inflowing happens when these areas connecting pressured underground water bearing rock bodies with excavating spaces. The computed relative displacements between the roof and bottom surfaces of the service roadway during excavation well match the measured data. Combining the distributions of principal stresses around the excavating space and deformations along horizontal lines with different depths under the coal layer, we can identify four advancing regions of deformation in the basement during coal excavation, i. e., nomal region before excavation, intensely compressing and compacting region before excavation, less compressing and expanding region under and after excavation, and normal region after excavation. The middle two regions are in more danger of water inflow.The model and its results can be applied to some other coal fields in North China.