考虑岩石应变软化的厚煤层综放开采覆岩破坏特征研究

Overburden Failure Characteristics with Caving Mining of Thick Coal Seam Considering Strain Softening

为了分析裴沟矿31采区的煤炭开采对上部魔洞王水库的影响,以及评价水体下开采的安全性,首先分析了岩土体材料在三轴压缩试验中表现出来的应变软化现象,认为岩石峰后的软化能够说明覆岩破坏后的力学特性;然后介绍了FLAC3D中应变软化模型;最后分别建立Mohr—Coulomb理想弹性模型和应变软化模型的数值模型,针对工作面推进过程中覆岩移动破坏的特征以及顶板导水裂隙带发育规律,分析了两者计算结果的差别,计算结果表明:应变软化模型对覆岩移动破坏特征的计算更加准确,能够说明工作面推进过程中覆岩移动规律,通过其计算得到的导水裂隙带高度的预计对水体下采煤的安全性评价有一定的参考价值。

In order to analyze impacts caused by mining of 31 mining area of Peigou coal mine for Modongwan reservoir, as well as evaluate safety of mining work under water, firstly this paper analyzes phenomenon of the rock material strain softening in triaxial compression test, manifesting that peak rock softening can explain the mechanical properties after overburden fail- ure ; then the strain softening model in the FLAC3D soft is introduced; finally ideal elastic - plastic and strain softening model of Mohr - Coulomb model are established for promoting the process of overburden rock face moves damage characteristics and development law of water flowing fractured zone, in which the differences between the two calculations are analyzed and the results show that： the strain softening model for moving overburden failure characteristics calculation is more accurate, can explain the process of face advance strata movement and height of water flowing fractured zone through calculating with strain softening can provide references of safety for mining under water.