To examine the evolution of overburden fissures in deep well hard top slab comprehensive re-lease mining,the optical frequency domain scattering technique for Brillouin scattering(BOFDA)is ap-plied to the physical similar model test.With the geological conditions of the first mining integrated working face of the 1 000-meter-deep shaft Xinhu coal mine as the engineering background,an overlying strata model is established in the laboratory to explore the response characteristics of overburden deformation and fiber strain during the recovery process using pre-buried sensing fibers.The optical fiber sensors are implanted into the working face roof by two boreholes 65 m strike,24.5 m in-clination,and 119 m vertical to monitor the migration and fragmentation pattern of overlying rock by ob-taining the strain data of the fiber optic of the mining roof during the advance of the working face.The model test results show that there is a correlation between the optical fiber strain curve and the deforma-tion characteristics of the overlying rock.The fiber-optic strain of overburden detachment,fracture,and cut-down point show a convex peak,which can characterize the evolution process of"three horizontal zones and three vertical zones"boundary characteristics of the overburden of the quarry.The variation of the convex peak range and peak size of the optical fiber strain curve is consistent with the development trend of the migration intensity of the overlying rock in the stope.Based on the response relationship be-tween fiber optic strain and overburden structure evolution,combined with the overburden lithology combination of 818 working face,the height of the"three zones"of the working face determined by an-alyzing the field fiber optic strain data is consistent with the model tests and theoretical calculations,which is in line with the actual situation of the mine,and verifies the reliability and accuracy of distribu-ted fiber optic monitoring technology in monitoring the structural Evolution of the overburden of the hard roof of deep shafts.The test results can serve as a reference for the study of the deformation and move-ment law of the overlying rock in the stope.
关键词
分布式传感光纤/光纤响应特性/采动裂隙/"两带"高度
Key words
distributed optical fiber sensing/response characteristics of optical fibers/mining fracture/"two zones"height
维普
万方数据