基于数字散斑技术的煤层群开采覆岩运移规律试验研究

为研究缓倾斜近距离煤层群开采时上覆岩层运移及含水层水动力演化规律,防止煤层群下行开采时发生突水事故,采用流固耦合相似模拟试验、应用数字散斑技术、理论分析等研究手段对某煤矿六采区综采工作面煤层群开采后的顶板变形破坏进行研究。结果表明:(1)14~#上组煤层开采过程中,隔离煤柱能够较好地控制顶板的移动变形,15~#下组煤层重复开采时会破坏上组煤层隔离煤柱,导致顶板的变形破坏加剧;(2)煤层群开采后覆岩位移传播方向为竖直方向,同一岩层位移呈现出中间下沉量大、两侧下沉量小的盆地特征;(3)应用数字散斑技术测得14~#上组煤层和15~#下组煤层开采后覆岩位移最大影响高度分别为29.0m和32.8m,与经验公式法计算结果进行对比,观测误差分别是1.8%和5.3%;(4)工作面依次下行开采14~#煤层和15~#煤层时,K_4含水层有发生突水的危险。

Experimental study on overlying strata migration law of coal seam group mining based on digital speckle pattern technology

In order to study the law of overlying strata migration and aquifer hydrodynamic evolution during mining of gently inclined and close distance coal seams, and to prevent water inrush accidents during downward mining of coal seams, the deformation and failure of roof of fully mechanized working face in No.6 mining area of a coal mine was studied by means of fluid solid coupling similar simulation test, digital speckle technology application and theoretical analysis. The results show that: 1) during the mining process of 14# upper group coal, the isolated coal pillar can better control the movement and deformation of the roof, while the repeated mining of 15# lower group coal will destroy the isolated coal pillar of upper group coal, resulting in the aggravation of roof deformation and failure; 2) after the mining of coal seams, the overlying strata displacement propagation direction is vertical direction, and the displacement of the same stratum presents the characteristics of large middle subsidence and small subsidence on both sides; 3) the maximum influence height of overburden displacement measured by digital speckle technology is 29 m and 32.8 m respectively after mining 14# upper group coal and 15# lower group coal, respectively. Compared with the calculation results of empirical formula method, the observation error is 1.8% and 5.3%; 4) K4 aquifer water inrush risk will occur when 14# coal seam and 15# coal seam are mined down successively.