Distributed optical fiber measurement of floor heave evolution in mining roadway

With the deepening of coal mining and the upsizing of mining equipment, the floor heave of the mining roadway has become an important problem that restricts the efficient and safe mining of the working face. It is of great significance to reveal the occurrence law of floor heave of the mining roadway for the stability control of the roadway floor. Based on the analysis of the deformation and failure characteristics of the mining roadway floor, com-bined with the key characteristics of the roadway floor heave, this paper studies the distributed optical fiber strain characterization method, and embeds the distributed sensing optical cable into the roadway floor through the borehole. Based on a large number of field measured data in the coal mine, the oc-currence of the roadway floor heave in the mining process of the working face is systematically analyzed. The results show that the distributed optical fiber has a positive strain peak and a negative strain peak respectively corresponding to the uncoordinated bending deformation characteristics of delamination and extrusion of the floor rock, and the local tension of the optical fiber corresponds to the crushing and extrusion expansion deformation characteristics of the floor rock. The strain value and strain growth rate of the optical fiber in the crushing characteristic area reflect the intensity of extrusion between the broken rock blocks. The evolution process of mining roadway floor heave is divided into three stages: disturbance, failure and relief uplift. The failure characteristics of floor strata in each stage are pointed out, and the key information of distributed optical fiber strain characteristic values in the crushing area in each stage is established. The conclusion of the study provides a new idea for the realization of large-scale distributed optical fiber monitoring of roadway surrounding rock, and has guiding significance for the floor heave control of mining roadway.