Cao Xiaofan, Wang Xiaoli, Liu Huihui, Wang Song, Wang Deyong, Liu Zhongping
School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, 710054, Shaanxi, China.
Shaanxi Pioneer Construction Technology Co., Ltd, Xi'an, 710054, Shaanxi, China.
Sci Rep. 2024 Jul 15;14(1):16335. doi: 10.1038/s41598-024-67211-6.
The technology of building a retaining roadway along goaf or a protecting roadway with a small coal pillar has been developed and applied for many years, and a satisfactory supporting effect has been obtained in medium-thick coal seam and thin coal seam mining. However, the gob-side roadway or small coal pillar mining in a thick coal seam is still subjected to technical problems occasioned by factors such as high roadway, high support pressure beside roadway, and waste of coal resources. To solve these problems, the author proposes an innovative technology of coal-free mining: the technology of driving roadway along goaf with a flexible formwork pre-cast wall. The article utilizes the 3503 and 3505 working faces of Wangzhuang Coal Industry Group as the research background, and comprehensively introduces the principle of the technology and the overburden rock movement law. Through theoretical calculations and numerical simulations, the support resistance and support parameters of flexible formwork pre-cast walls have been determined and successfully performed in industrial practice. The results indicate that the combination of the flexible mould pre-cast wall coal pillar-free mining technology and roof cutting process is more conducive to the maintenance of the roadway in the lower working face, and effectively reduces the stress and deformation of the surrounding rock. The roof and floor of the drivage roadway move, and the deformation of the two sides is small; furthermore, the overall roadway retention effect is satisfactory, which meets the requirements of mining in the lower working face. The coal pillar pertaining to the 20 m section of the 5 m high mining height face was recovered for Wangzhuang Coal Mine, and the recovery rate of the coal resources and the driving speed of the roadway were improved. The proposed method can be popularised and applied in this mine and even in the mining of 15# large-height coal seams in the two cities.
沿空留巷或留小煤柱护巷技术已发展应用多年，在中厚煤层和薄煤层开采中取得了良好的支护效果。然而，厚煤层沿空巷道或小煤柱开采仍面临巷道高度大、巷道旁支承压力高、煤炭资源浪费等因素带来的技术难题。为解决这些问题，作者提出了一种创新的无煤柱开采技术：柔性模板预制墙沿空掘巷技术。本文以王庄煤业集团3503和3505工作面为研究背景，全面介绍了该技术原理及覆岩移动规律。通过理论计算和数值模拟，确定了柔性模板预制墙的支护阻力和支护参数，并在工业实践中成功应用。结果表明，柔性模板预制墙无煤柱开采技术与切顶工艺相结合，更有利于下部工作面巷道的维护，有效降低了围岩应力和变形。掘进巷道顶底板移近，两帮变形较小；巷道整体留巷效果良好，满足下部工作面开采要求。王庄煤矿回采了5m采高工作面20m区段的煤柱，提高了煤炭资源回收率和巷道掘进速度。该方法可在该矿乃至两市15#大采高煤层开采中推广应用。
