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    高应力软岩巷道变形机理及帮顶协同控制技术

    Deformation mechanism and sidewall-roof collaborative control technology of high-stress soft rock roadway

    • 摘要: 为解决采动影响下高应力软岩巷道围岩变形控制难题,以雅店煤矿高应力软岩巷道为研究背景,分析了巷道围岩变形破坏特征及采动应力演化规律,测试了巷道围岩地应力及围岩矿物成分与含量,揭示了巷道围岩变形影响因素及机理。结果表明:雅店煤矿高应力软岩动压巷道全断面收缩大变形破坏特征突出,高应力及强采动是造成巷道大变形破坏的主要驱动力,在高应力及强采动影响下巷帮内挤变形最为突出,造成巷帮煤体完整性及强度发生由浅入深的持续弱化,锚杆基本失效,巷帮大变形加剧了底板软岩底鼓,进而诱发了巷道全断面收缩变形;雅店煤矿高应力软岩动压巷道变形机理在于帮顶支护失调,巷帮的大变形破坏加剧了顶底板的整体变形。基于此提出了高预应力强帮护顶支护技术。通过顶板锚杆(索)补强支护,抑制顶板岩层的离层变形,巷帮注浆加固提高破碎煤体完整性及承载能力,结合高预应力锚杆(索)支护提高巷帮支护强度及围岩稳定性。井下应用效果表明,采动影响下顶板基本未发生下沉变形,巷帮内挤变形减小66.7%,底板变形明显减小,取得了较好的高应力软岩巷道变形控制效果。

       

      Abstract: To address the difficulty of controlling surrounding rock deformation of high-stress soft rock roadways under mining influence, taking the high-stress soft rock roadway of Yadian Coal Mine as the research background, this paper analyzes the deformation and failure characteristics of roadway surrounding rock and the evolution law of mining-induced stress. The in-situ stress of roadway surrounding rock as well as the mineral composition and content of surrounding rock were tested, and the influencing factors and mechanism of roadway surrounding rock deformation were revealed. The results show that the high-stress soft rock dynamically pressurized roadway in Yadian Coal Mine presents prominent failure characteristics of large deformation and full-section shrinkage. High in-situ stress and strong mining-induced effect are the main driving forces causing large deformation and failure of the roadway. Under the influence of high in-situ stress and strong mining-induced stress, the inward squeezing deformation of roadway side is the most prominent, which leads to continuous weakening of the integrity and strength of roadway side coal mass from shallow to deep, makes rock bolts basically fail, and the large deformation of roadway side aggravates the floor heave of soft rock in floor, thereby inducing full-section shrinkage deformation of the roadway. It is revealed that the deformation mechanism of high-stress soft rock dynamically pressurized roadway in Yadian Coal Mine lies in the imbalance of roadway side and roof support; the large deformation and failure of roadway side aggravate the overall deformation of roof and floor. On this basis, a high pre-stress support technology of strengthening roadway side and protecting roof is proposed. The supplementary support of roof rock bolts (cables) is adopted to restrain bed separation and deformation of roof strata. Grouting reinforcement of roadway side is used to improve the integrity and bearing capacity of fractured coal mass, and combined with high pre-stress rock bolts (cables) support to enhance the support strength of roadway side and surrounding rock stability. The underground application results show that under mining influence, almost no subsidence deformation occurs in the roof, the inward squeezing deformation of roadway side is reduced by 66.7%, and the floor deformation is significantly decreased, achieving a good control effect on the deformation of high-stress soft rock roadways.

       

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