浅埋煤层快速掘进巷帮蠕变效应及滞后支护

Creep effect and lag support of laneway’s side in rapid excavation of shallow seam

为确定榆神府矿区浅埋煤层煤巷掘进两帮合理滞后支护时间,提高掘进速度,避免采掘接续紧张,以张家峁煤矿14213胶带运输巷为研究对象,采用巷道围岩松动圈理论分析巷道围岩稳定性,确定两帮滞后支护的可行性;根据围岩蠕变规律,确定合理的巷道滞后支护时机和煤巷围岩蠕变采用的流变模型;采用FLAC3D软件和Cvisc流变模型模拟14213胶带运输巷掘进过程中不同滞后支护时间的两帮蠕变规律,确定合理的两帮滞后支护时间。结果表明:14213胶带运输巷开挖28 d以内,顶板及时支护条件下,两帮移近量较小;掘进29 d后两帮出现加速蠕变现象,两帮移近速率最大达到36 mm/d,为稳定蠕变阶段均值的18倍,塑性区最大发育深度达到1.3 m,两帮稳定性明显下降。巷道掘进28 d两帮进行滞后支护后,两帮未出现加速蠕变,塑性区发育深度0.5 m,比两帮不支护减小61.5%,巷道两帮稳定。研究结果在矿区成功应用,为煤巷掘进滞后支护提供科学依据。

In order to determine the reasonable lag supporting time of two ribs of excavated roadway of the shallow coal seam in Yushenfu mining area,improve the driving speed and avoid the tension of mining and drifting,take the 14213 belt headgate of Zhangjiamao Coal mine is taken as the research object.The stability of the surrounding rock in the roadway is analyzed by using of the loose circle theory of surrounding rock,and the feasibility of two ribs lag supporting is determined.According to the creep law of surrounding rock,the reasonable lag support time of roadway and the rheological model of surrounding rock creep of coal roadway are determined.FLAC~(3D)software and Cvisc rheological model are used to simulate the creep law of two ribs with different lag support time in the process of 14213 belt headgate excavation,and the reasonable lag support time of two ribs is determined.The research shows that within 28 days of excavation of 14213 belt headgate,the displacement of two ribs is small,under the condition of roof support immediately.After 29 days of excavation,in two ribs occurs accelerated creep and the maximum creep rate of two ribs reaches 36 mm/d,which is 18 times of the average value in steady creep stage.The maximum development depth of plastic zone reaches 1.3 m,and the stability of two ribs decreases obviously.After 28 days of entry excavation,in two ribs does not occur accelerated creep thanks to lagging support.The development depth of plastic zone was 0.5 m,61.5%less than that of two ribs without support,and the two ribs of entry was stable.The successful application of the research results in the mine provides a scientific basis for the lagging support of coal roadway excavation.