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沿空留巷围岩卸压支护协同控制技术研究

Research on collaborative control technology for surrounding rock pressure relief and support of gob-side entry

  • 摘要: 为解决沿空巷道受相邻采空区未断裂基本顶形成的悬臂梁支承压力影响的问题,采用水力压裂顶板卸压的方法,对采空区基本顶提前压裂,尽量减少相邻采空区基本顶形成悬臂梁结构,从而降低和转移沿空巷道顶板所受支撑压力的强度。在此基础上采用柔膜袋充填混凝土在沿空巷道和采空区间做假墙,对充填混凝土进行井下强度测试,同时对沿空巷道顶板以及所做的假墙进行强力锚网支护,使其最大限度恢复到三向应力状态,提高其抗载能力。通过现场假墙压应力和顶底板移近量监测对比表明:进行水力压裂卸压后,假墙承受沿空巷道顶板最大压应力为21 MPa,比未进行水力压裂卸压区域所受压应力降低了36.4%;沿空巷道顶底板移近量为320 mm,降低了46.5%。水力压裂卸压后,极大改善了3109辅助进风巷的应力环境,降低了沿空巷道顶底板移近量,保证了沿空巷道的安全使用,有效的缓解采掘紧张的局面。

     

    Abstract: In order to solve the problem of the support pressure of the cantilever beam formed by the unbroken main roof in the adjacent gob, the hydraulic fracturing roof pressure relief method is adopted to pre-fracture the main roof in the gob and minimize the adjacent mining. The canopy structure is basically formed in the roof of the gob, there by reducing and transferring the strength of the supporting pressure on the roof of the gob-side entry. On this basis, the soft film bag filling concrete is used as a artificial wall in the gob-side entry and gob section, and the underground strength test of the filled concrete is carried out. At the same time, the roof of the gob-side entry and the artificial wall are strongly anchored and supported by the mesh to make it recover to three-dimensional stress state to the maximum extent and improve their load resistance. The comparison between the pressure stress of the artificial wall and the displacement of the roof and floor shows that after hydraulic fracturing and decompression, the maximum compressive stress of of the roof of the roadway is 21 MPa, which is 36.4% lower than the area without hydraulic fracturing and pressure relief; the displacement of the roof and floor in the gob-side entry is 320 mm, which is reduced by 46.5%. After hydraulic fracturing and pressure relief, the stress environment of No.3109 auxiliary air intake roadway has been greatly improved, the displacement of the roof and floor of the gob-side entry has been reduced, the safe use of the gob-side entry has been ensured, and the tension of mining has been effectively relieved.

     

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