不同石灰岩顶板厚度下的黄泥顶板变形特性研究

Study on Deformation Characteristics of Yellow Mud Roof under Different Limestone Roof Thickness

为解决石丘煤业主采煤层顶板黄泥岩的剧烈变形问题,采用FLAC3D数值模拟软件建立下不同石灰岩顶板与黄泥顶板厚度的数值模型,对围岩变形、垂直应力、矢量位移与体积应变进行监测,探究不同厚度石灰岩顶板对不同厚度黄泥顶板变形特性的影响。结果表明,石灰岩厚度小于6 m并且黄泥岩厚度小于3.5 m时,最大顶板下沉量变化较小;石灰岩厚度小于6 m并且黄泥岩厚度大于3.5 m时,顶板最大下沉量随黄泥岩厚度的增加迅速增加;当石灰岩的厚度大于6.0 m,最大离层量随黄泥岩厚度的增加而减小。根据数值模拟结果以及工程现场的顶板实际破碎形态,提出了离层破碎型、离层膨胀型、膨胀蠕变型顶板变形特征以及相应的支护方式。

In order to solve the severe deformation of yellow mudstone in the coal seamroof of Shiqiu Coal Mine,numerical models of different thickness of limestone roof and yellow mud roof were established by using FLAC^(3D)numerical simulation software,and thesurrounding rock deformation,vertical stress,vec⁃tor displacement and volume strain of surrounding rock were monitored to explore the influence of different thickness of limestone roof on deformation characteristics of different thickness of yellow mud roof.The re⁃sults show that the maximum roof subsidence changes little when the thickness of limestone is less than 6 m and the thickness of yellow mudstone is less than 3.5 m.When the thickness of limestone is less than 6 m and the thickness of yellow mudstone is more than 3.5 m,the maximum roof subsidence increases rapidly with the increase of yellow mudstone thickness.When the thickness of limestone is more than 6.0 m,the maximum amount of separation decreases with the increase of the thickness of yellow mudstone.According to the results of numerical simulation and the actual fracture form of the roof at the engineering site,the de⁃formation characteristics of the roof of the breaking-apart type,the expansion type,the expansion creep type and the corresponding supporting modes are put forward.