山西阳泉矿区刘村采煤塌陷机理及数值模拟

Mechanism and Numerical Simulation of Liucun Coal Mining Subsidence of Yangquan Mining Area in Shanxi

选取山西阳泉矿区单煤层开采引发的强烈地面塌陷作为研究对象,在详细介绍刘村采煤塌陷所处地质环境背景及其发育变形特征的基础上,根据区域岩体工程地质特征,将其划分为12层岩组;运用关键层、复合关键层理论对采煤塌陷机理进行了分析,获取Hoek-Brown岩体力学参数;采用Flac5.0 Extrusion对刘村采煤塌陷坑进行了反演模拟。数值模拟反映各阶段采动裂缝在地表的发育分布情况并计算了最终沉降量,覆盖层裂缝自然修复周期为2个月,基岩裂缝自然修复周期为3个月;采动裂缝最终在平面上呈“θ”形,塌陷中心1和塌陷中心2最终沉降量分别达到4.5 m和4 m,塌陷面积是工作面面积的1.85倍。模拟结果与调查监测数据高度吻合,客观地反映了地表变形和深部覆岩塌陷的发展变化过程,为塌陷机理分析起到了帮助作用。该套岩体力学参数与模拟方法适用于阳泉矿区采煤塌陷精准预测。

In this paper,we investigated the single seam coal mining subsidence,and introduced in detail the geo-environment background,developing features and deformation characteristics of the Liucun coal mining subsidence of Yangquan mining area in Shanxi.Based on the geological characteristics of the rocks,12 groups were divided and their formation mechanism was analyzed by key stratum and composite key stratum theory.Subsequently,the Hoek-Brown rock mechanical parameters were obtained,followed by inverse modeling by Flac5.0 Extrusion.Numerical simulation reflects the development and distribution of mining-induced fissures on the surface at different stages,and calculates the final magnitude of subsidence.The natural recovery period of fissures in overburden and bedrocks was estimated to be 2 and 3 months,respectively,and the fissures finally present a“θ”shape in the plane.The final magnitudes of No.1 and No.2 coal mining subsidence centers reach 4.5 m and 4 m,respectively,with the subsidence area being 1.85 times of the workface area.The results are highly consistent with the survey monitoring data,and can reflect the development process of the surface deformation and deep overburden collapse accurately,which is beneficial to subsidence mechanism analysis.The rock mechanical parameters and the simulation methods are applicable to accurate prediction on mining subsidence in Yangquan mining area.