Abstract: To optimize the width of protective coal pillar of shallowly buried pipeline in the coal mining subsidence area, the gas-coal superposition area in Ordos Basin is taken as the engineering background. The theoretical algorithm of pipeline tensile strain is proposed using the probability integral method. According to the tensile strain limit, the prediction model of the width of the pipeline protective coal pillar in the subsidence area is established and verified by comparison through numerical analysis and engineering application. Then the distribution and evolution of tensile, volumetric and shear strains of adjacent buried pipelines during the advancing process of the panel are analyzed. The results show that the prediction method greatly shortens the width of the pipeline protective coal pillar and improves the recovery rate of coal resources under the premise of ensuring safety. With the decrease in the horizontal distance between the panel and pipeline, the tensile amount and the tensile strain of the whole pipeline grow exponentially. However, the tensile increment shows a trend of increasing first and then decreasing. As the panel becomes closer to the pipeline, the volumetricstrain distribution shows a ‘V’ shape in the axial direction and an ‘M’ shape in the circumferential direction. However, the shear strain distribution of the pipeline shows a ‘W’ shape in the axial direction and ‘’ shape in the circumferential direction. As the panel advances, the volumetric and shear strains are exponential functions of the horizontal spacing of the panel pipeline. The locations where the pipeline is mostly prone to damage are the center and edge of the subsidence area, and similar working conditions require focused attention. The application of our method is conducive to the accurate and coordinated mining of oil, gas and coal resources. Meanwhile, the investigation of multi-parameter mechanical characteristics is helpful to provide decision support for the correction of prediction results and preventive maintenance.

Key words: mining engineering, buried pipeline, protective coal pillar, tensile strain, volumetric strain, shear strain