工作面顶板岩层变形破坏发育过程光纤测试模拟研究

Simulation study on development process of overburden strata deformation and failure in working face with optical fiber testing

回采工作面顶板岩层的变形与破坏过程一直是矿山地质的重点研究对象,获得其动态发育特征对于矿井安全生产十分重要。文章基于分布式光纤传感测试技术,通过构建室内平面应力模型,在煤层采动区布设4条斜向和3条竖向测线。根据煤层开挖进度,定期采集岩层应变值,从而获得煤层开挖过程中岩层变形破坏动态发育规律。结果表明:煤层开挖过程中,工作面前方顶板岩层受超前支承压力的作用将呈现压应变,而工作面及后方采空区上部岩层则主要以拉伸破坏为主;根据竖向光缆应变变化曲线分析得出11-2煤垮落带发育高度为10 cm,导水裂缝带发育高度为45 cm,光缆测试结果与模型实际测量结果基本一致;光缆应变曲线可良好地分辨岩层变形破坏发育过程。研究结果表明,利用分布式光纤监测岩层结构的变形与破坏过程可获得良好的岩层应变参数,其可分辨能力强、效果显著。

The deformation and failure process of the overburden strata of the mining face has always been the key research object of mine geology,and obtaining its dynamic development characteristics is very important for mine safety production.In this paper,based on the distributed optical fiber sensing technology,by constructing the indoor plane stress model,and four oblique lines and three vertical lines were arranged in the mining area of the coal seam.According to the progress of coal seam excavation,the strain value of the rock strata was collected regularly,and the dynamic development laws of rock strata deformation and failure were obtained during the excavation of coal seam.The results demonstrate that during the excavation of coal seam,the overburden strata in front of the working face will be subjected to compressive strain due to the advanced abutment pressure,while the overburden strata in the working face and the mined area will mainly be tensile failure;according to the analysis of strain curve of the vertical optical cable,the development height of the 11-2 coal caved zone was 10 cm,and the development height of the fractured zone was 45 cm,the optical cable testing results were basically consistent with the actual measurement results of the model;the strain curve of optical cable can well distinguish the deformation and failure development process of the rock strata.It can be obtained that using the distributed optical fiber to monitor the deformation and failure process of the rock strata structure can obtain the rock strata strain parameters well,and its resolvability is strong and the effect is remarkable.