应力拱效应下裂隙场演化规律及应用

Evolution Law and Application of Fracture Field under Stress Arch Effect

为研究九龙矿覆岩裂隙场演化规律,运用数值模拟、理论分析相结合的方法,开展应力拱效应下裂隙场的演化规律研究,得到了断裂离层高度、断裂角、应力拱及拱脚位置随推进距离变化的演化规律,并建立应力拱模型,得到各参量与应力拱高度的量化关系。结果表明:裂隙场可分为靠近煤壁侧的裂隙区、中部的压实形成区、压实扩展区、工作面右侧的裂隙区和塑性区裂隙区,离层裂隙的高度和断裂角随着周期来压呈阶段性增长;应力拱位于上覆岩层塑性裂隙区和采场周围煤岩体中,近似呈半椭圆形分布,应力拱的拱脚作用在工作面前后方和侧翼未采煤层支承压力峰值区,应力峰值区距开切眼的距离是动态变化的;建立应力拱模型,得到断裂角、推进距离、断裂离层高度、拱脚距煤壁距离与应力拱高度的量化关系,求得应力拱高并结合数值模拟结果进行工程实践,有效地预计了裂隙带高度,保证了工作面的安全开采。

In order to study the evolution law of fissure field in Jiulong mine,numerical simulation and theoretical analysis are combined to study the evolution law of fracture field under the stress arch effect.The evolution law of fracture separation height,fracture angle,stress arch and arch foot position with the change of advancing distance is obtained,and the stress arch model is established to obtain the quantitative relationship between each parameter and stress arch height.The results show that:the fracture field can be divided into the fracture zone near the side of the coal wall,the compaction formation zone in the middle,the compaction expansion zone,the fracture zone on the right side of the working face and the fracture zone in the plastic zone.The height and fracture angle of the separated fracture increase periodically with the periodic weighting;the stress arch is located in the plastic fracture zone of the upper strata and the surrounding coal and rock mass,which is approximately semi-elliptic distribution.The arch foot of the stress arch acts on the peak area of the abutment pressure of the unmined coal seam behind the working face and the flank,and the distance between the peak area of the stress and the open cut is dynamic;the stress arch model is established to obtain the quantitative relationship between the fracture angle,the advancing distance,the fracture separation height,and the distance between the arch foot and the coal wall and the stress arch height.The stress arch height is obtained and the engineering practice is carried out combined with the numerical simulation results.The height of the fracture zone is effectively predicted to ensure the safe mining of the working face.