Design of a Deformable Pipeline for Efficient Recovery of Protective Coal Pillars
摘要
The conventional approach uses the horizontal distance between the ground subsidence boundary and the panel to design the width of the pipeline protective coal pillars, which results in abundant coal resources in the inability to recover. To increase its recovery rate, a pathway for efficiently recovering the coal pillar is developed by designing a new deformable pipeline. First, understanding the position relationship between the coal pillar and the pipeline. Second, predicting the ground subsidence range after coal pillar mining. Next, dismantle the pipeline segment within the subsidence area. Then, mining the coal pillar and calculating the subsidence duration. Finally, a U-shaped expansion pipeline will be laid in the subsidence area after ground movement stabilizes. Among them, the calculation methods for predicting the ground subsidence range after coal pillar mining and the pipeline length within the subsidence area were presented. Two prediction models for the duration of ground subsidence in both cases with/without ground settlement monitoring data were established. A U-shaped expansion pipeline consisting of elbows, standpipes, expansion joints and horizontal pipes was designed. Combined with the pathway’s operation characteristics, a flowchart for optimizing operational and improving parameters and a Gantt chart for time-coordinated were proposed. The case study shows that the length of the 5119 m pipeline protection coal pillar is shortened to 788 m, the recovery of coal pillars is 1.63 × 107 t, and the recovery rate is increased by 84.5%. The pathway realizes the efficient recovery of coal pillar and effectively promotes the coordinated mining of gas–coal resources.