采动覆岩注浆离层力学结构模型及稳定性预测方法:以张集煤矿为例

Mechanical Structure Model and Stability Prediction Method of Mining-induced Overburden Grouting Layer Separation:Taking Zhangji Coal Mine as an Example

煤矿开采引发地表岩土层移动变形,进而导致建筑倒塌、生态环境破坏等问题,离层注浆是减缓地表沉降的重要手段之一。为了研究淮南矿区倾斜地层采动离层的发育和稳定性,基于关键层理论,建立了由主关键层、注浆阻隔层、亚关键层组成的采动覆岩注浆离层力学结构模型,提出了注浆离层稳定性力学判据。采用离散元数值模拟分别建立水平和倾斜地层模型,模拟煤层开采过程中裂隙演化规律及可注浆离层发育情况。结果表明,水平和倾斜地层导水裂隙均未贯通注浆阻隔层,主关键层底部均发育可注浆离层,水平地层可注浆离层开度比倾斜地层的开度更大。数值模拟证明采动覆岩注浆力学结构模型可以对采动离层稳定性进行有效预测。

Coal mining causes the movement and deformation of the overburden strata,which leads to the buildings collapse and the ecological environment destruction.To study the development law and stability of mining-induced separation layer in inclined strata of Huainan mining area,based on the key strata theory,an engineering geomechanical model of mining-induced overburden grouting consisting of main critical strata,grouting barrier layer and sub-critical strata was proposed,and the mechanical criterion of stability of grouting separation layer was established.Further,using discrete element numerical simulation,horizontal and inclined strata models were respectively built to simulate the evolution law of fractures and the development of grouting separation beds during coal seam mining.The results show that the grouting barrier layer is not penetrated through the water-conducting fractures in both horizontal and inclined strata.The grouting separation layer is developed at the bottom of the main key strata,and the opening of grouting separation layer in horizontal strata is larger than that in inclined strata.The numerical simulation proves that the engineering geomechanical model of mining-induced overburden grouting can effectively predict the reliability of developed separated strata.