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陈绍杰,刘江伟,李亚康,等. 底板动压巷道压裂弱结构体应力转移控制技术[J]. 煤炭科学技术,2024,52(1):106−116. DOI: 10.12438/cst.2023-1644
引用本文: 陈绍杰,刘江伟,李亚康,等. 底板动压巷道压裂弱结构体应力转移控制技术[J]. 煤炭科学技术,2024,52(1):106−116. DOI: 10.12438/cst.2023-1644
CHEN Shaojie,LIU Jiangwei,LI Yakang,et al. Stress transfer control technology for fracturing weak structural bodies in subgrade dynamic pressure roadways[J]. Coal Science and Technology,2024,52(1):106−116. DOI: 10.12438/cst.2023-1644
Citation: CHEN Shaojie,LIU Jiangwei,LI Yakang,et al. Stress transfer control technology for fracturing weak structural bodies in subgrade dynamic pressure roadways[J]. Coal Science and Technology,2024,52(1):106−116. DOI: 10.12438/cst.2023-1644

底板动压巷道压裂弱结构体应力转移控制技术

Stress transfer control technology for fracturing weak structural bodies in subgrade dynamic pressure roadways

  • 摘要: 为了满足煤矿安全生产的需要,许多巷道都会布置在煤层底板中,如部分运输大巷、排水巷道、瓦斯抽采巷道等。采动应力容易造成底板巷道围岩应力升高,加剧底板巷道围岩变形,造成支护永久失效、顶板下沉、巷道底鼓、两帮收敛等破坏。针对此,提出了在应力传递路径上实施水力压裂,在指定的区域制造出一定空间形态的水压裂缝网,形成压裂弱结构体,实现区域范围内的应力转移,从而降低巷道区域范围内的应力,控制巷道的围岩稳定性的控制技术,并通过理论分析及现场工程验证等方式,揭示了底板动压巷道压裂弱结构体应力转移的力学机制,建立了相应的力学模型,对压裂弱结构体的合理位置、范围等影响因素进行了求解。得出:①压裂弱结构体使局部应力场发生明显变化,出现应力升高区和应力降低区,应力降低区主要分布在弱结构体与采动应力连线的方向上,主要集中在一个拱形的范围内;由于膨胀效应,在与应力来源垂直的方向上产生应力集中,出现应力升高区。②最大主应力变化幅度与压裂弱结构体的长轴长L、短轴长H、到巷道的距离P、与巷道连线的水平夹角β、压裂层的强度C及内摩擦角α、压裂的损伤变量D等有关。其中到巷道的距离P对卸压效果影响最大,损伤变量D对卸压效果影响最小。③采用提出的计算方法设计了淮北矿业集团袁店一矿的103运输集中巷的卸压方案,工程应用结果表明,底板动压巷道变形速率明显减缓,验证了底板强动压巷道压裂弱结构体应力转移模型的合理性。

     

    Abstract: In order to meet the needs of safe production in coal mines, many roadways are arranged in the bottom plate of coal seams, such as part of transportation alleys, drainage roadways, and gas extraction roadways. The mining stress generated by the working face causes the stress increase of the surrounding rock of the floor roadway through the transmission of the floor rock strata. It exacerbates the deformation of the surrounding rock of the floor roadway, which is easy to cause permanent support failure, roof sinking, dropsy at the bottom of the roadway, convergence of the two gangs, and other damages. In response to this, a control technology is proposed to implement hydraulic fracturing in the stress transfer path, creating a network of hydraulic fractures with a certain spatial pattern in the designated area, forming a fractured weak structural body, realizing stress transfer within the area, thus reducing the stress within the area of the roadway, and controlling the stability of the perimeter rock of the roadway, and through theoretical analysis and field engineering verification, the mechanical mechanism of stress transfer of weak structures in floor dynamic pressure roadway fracturing is revealed, the corresponding mechanical model is established, and the influence factors such as reasonable location and range of weak structures are solved. The results show that: ① Fracturing weak structure causes obvious changes in local stress field, and there are stress increasing zone and stress decreasing zone, and the stress decreasing zone is mainly distributed in the direction of the connection between weak structure and mining stress, mainly concentrated in an arch range; Due to the expansion effect, the stress concentration occurs in the vertical direction of the stress source, and the stress rise area appears. ② The magnitude of maximum principal stress change is related to the long axis L, short axis H, distance P to the roadway, horizontal angle β to the roadway line, strength C and internal friction angle α of the fractured layer, and damage variable D of the fracture in the weak structural body of the fracture. ③ The proposed method is used to design the pressure relief scheme of 103 belt concentrated roadway in Yuandian No. 1 Mine of Huaibei Mining Group. The engineering application results show that the deformation rate of roadway under dynamic pressure of floor is significantly reduced, and the rationality of the stress transfer model of fractured weak structure in roadway under strong dynamic pressure of floor is verified.

     

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