坚硬厚煤层大采高综采支架分段调阻煤壁弱化研究

Study on the weakening of coal wall with section resistance adjustment of fully mechanized support in hard thick coal seam with large mining height

  • 摘要: 不同回采阶段作用于煤壁−支架上的载荷变化较大,煤壁低效截割是支架阻力与回采阶段不匹配、矿山压力不能有效破煤的结果。支架分段调阻技术在满足不同回采阶段(周期来压前、正常回采、周期来压后)顶板安全控制的要求下,调整支架工作阻力改变煤壁上的载荷用于压裂破煤,能有效解决厚硬煤壁弱化的难题。以杨伙盘煤矿1102综采工作面为工程背景,研究了与回采阶段匹配的厚硬煤层支架分段调阻技术。模拟分析结果表明:① 在工作面正常回采阶段和来压阶段,煤壁测线上各点支承压力峰值、影响范围随液压支架初撑力增大而减小;相同支架初撑力作用下,来压阶段煤壁上支承压力峰值和影响范围均大于正常回采阶段。② 当液压支架初撑力由2 000 kN增至8 000 kN时,煤壁水平位移值在来压阶段减小了17 mm,在正常回采阶段减小了7.5 mm,说明降低支架初撑力有利于坚硬煤壁弱化。③ 不同回采阶段,围岩塑性区的破坏程度随液压支架初撑力的增加而降低,说明煤壁破坏程度减小。④ 正常回采阶段支架阻力为6 000~8 000 kN、周期来压后支架阻力为4 000~6 000 kN、周期来压前支架阻力大于8 000 kN,可以保证顶板安全和厚硬煤壁高效截割。现场应用表明:① 液压支架在115个工作循环中增阻状态占统计循环数的64.8%(1次增阻型占75.50%,2次增阻为20.16%,多次增阻为4.34%);支架活柱伸缩量在0~3%的比率为90%,说明现场生产中液压支架运转和控顶能力良好。② 分段调整液压支架工作支护阻力后,在有效控顶前提下,采煤机平均割煤时间降低至1.8 h,降低了21.7%,有效实现煤壁弱化,提高了割煤效率。

     

    Abstract: The load acting on coal wall-support in different mining stages varies greatly. The low efficiency cutting of coal wall is the result of the mismatch between the support resistance and mining stage, and the incapability of the mine pressure to effectively break the coal. The support section resistance adjustment technology can meet the requirements of roof safety control in different mining stages (before periodic pressure, normal mining, after periodic pressure), adjust the support working resistance to change the load on the coal wall for fracturing and breaking coal, which can effectively solve the problem of thick and hard coal wall weakening. Based on the engineering background of 1102 fully mechanized working face in Yanghuopan Coal Mine, the technology of support section resistance adjustment in thick hard coal seam matching with mining stage is studied. The simulation results show the following points. ① The peak value and influence range of support pressure at each point of coal wall survey line decrease with the increase of initial support of hydraulic support in normal mining stage and pressure stage of working face. Under the same initial support, the peak value and the influence range of the support pressure on the coal wall in the pressure stage are larger than those in the normal mining stage. ② When the initial support of hydraulic support increases from 2000 kN to 8000 kN, the horizontal displacement of coal wall decreases by 17 mm in the pressure stage and 7.5 mm in the normal mining stage, indicating that reducing the initial support is conducive to weakening the hard coal wall. ③ In different mining stages, the damage degree of plastic zone of surrounding rock decreases with the increase of initial support of hydraulic support, indicating that the damage degree of coal wall decreases. ④ The support resistance is 6000-8000 kN in normal mining stage, 4000-6000 kN after periodic pressure, and more than 8 000 kN before periodic pressure, which can ensure the safety of roof and efficient cutting of thick and hard coal wall. The field application shows the following points. ① In 115 working cycles, the increased resistance state of the hydraulic support accounts for 64.8% of the statistical cycles (75.50% for the first resistance increasing type, 20.16% for the second resistance increasing type and 4.34% for the multiple resistance increasing type). The ratio of the expansion and contraction of the support movable column between 0-3% is 90%, indicating that the hydraulic support has a good capability to operate and control the roof in the field production. ② After adjusting the support resistance of the hydraulic support in sections, the average coal cutting time of the shearer is reduced to 1.8 h under the premise of effective roof control, which is reduced by 21.7% . The coal wall is weakened effectively, and the coal cutting efficiency is improved.

     

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