Study of Deformation Mechanism on the Pipeline in Steep Longer Distance Seams Mining

In order to understand the deformation mechanism on the pipeline in steep longer distance seams mining, taking one coal mine as case study, where the gas pipeline from Shanshan to Urumqi, in China is laid across. FLAC(3D) was adopted to study the deformation mechanism on the pipeline. The simulations reveal that little deformation occurred on the pipeline above the untapped thinner seam after the thicker seam mining, whereas vertical displacement increase about 27.5% on the pipeline above the mined thicker seam after the thinner seam mining, and the maximum deformation on the pipeline is at the location of about the centre of gob in the thicker seam, but no obvious deformation on the pipeline appeared above the rocks between the mined two seams; The possible damage to the pipeline occurs at the peak compressive stresses, which are at the gob centre, then at the two peak tensile stresses, which are at the outer edge of gob in the thicker seam. Therefore, the results are helpful to prevent and reduce the impact of subsidence on the pipeline.