煤层底板岩体采动渗流场–应变场耦合分析

根据五沟煤矿1018工作面地质及水文地质条件,应用三维快速拉格朗日(FLAC3D)流固耦合分析模块,采用变渗透系数方法,对该工作面底板岩体采动渗流应变机制进行数值模拟研究。分析结果表明:采动影响下,围岩渗透系数发生较大的变化,处在采空区正上方的泥岩段最大达到原始渗透系数的1 293倍;根据渗流场分析,工作面采动并没有破坏底板隔水层的阻水性能,采动裂隙没有导通灰岩含水层,灰岩水涌入回采工作面形成水害可能性较小;工作面正下方岩体单元安全度小于1的区域最大深度为30 m。综合渗流场以及隔水底板单元安全度分析结果,10煤底板下灰岩水溃入工作面形成水害可能性较小。

SEEPAGE FIELD-STRAIN FIELD COUPLING ANALYSIS FOR ROCK MASSES OF COAL SEAM FLOOR DURING MINING ABOVE A CONFINED AQUIFER

Based on the geological and hydrogeological conditions of the face 1018 in Wugou coal mine,the fluid-solid coupling module in FLAC3D with changeable permeability coefficient is adopted to simulate the whole process of damage and failure of rock masses at floor of the coal seam No.10.The results indicate that the permeability coefficient of surrounding rocks changes a lot due to mining.The maximum permeability coefficient reaches 1 293 times of the original one,which happens at the immediate roof of mined-out area.According to the analysis of seepage field,mining does not destroy water resistance of floor aquifer.Mining fissures do not connect limestone aquifers,and water in the limestone is less likely to flow into stopes to cause damage.The maximum depth of rock masses with element safety degree less than one is about 30 m.According to the change of permeability coefficient of and the analytical results of element safety degree of rock masses,safe mining of the face 1018 can be ensured.