Comparative study on control effect of deep roadway under full-length prestressed bolt-grouting support
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摘要: 本文基于后注浆的全长预应力锚注支护工艺,并通过对FLAC3D软件中内嵌PILE结构单元修正,提出了全长预应力锚注支护数值模拟方法。在此基础上,开展了地应力、原岩强度等级、支护构件长度、布设间距、注浆强化指数与预应力6种因素下巷道围岩控制效果数值模拟对比研究,揭示了各类因素对围岩变形量、塑性区演化的影响规律,构建了全长预应力锚注支护下控制效果敏感性评价指标,将影响因素依次划分为围岩强度、地应力、锚注支护构件设计3个层级,并根据各因素敏感性层级给出了工程措施建议。最后,以现场典型软弱破碎地层巷道为工程依托,研发了具有强度高、可施加预应力等优势的组合式高强注浆锚杆与高强中空注浆锚索。通过现场应用,验证了全长预应力锚注支护可有效增强软弱破碎围岩自承载能力,充分发挥锚固构件的支护潜力,限制巷道围岩变形破坏。Abstract: This study proposed the numerical simulation method of full-length prestressed anchor grouting support based on the post-grouting technology, and the modification of the embedded PILE structural unit in FLAC3D software. Specifically, we conducted the numerical simulation and made comparison in terms of the control effect of roadway surrounding rock under six types of factors: ground stress, strength grade of original rock, length of supporting members, layout spacing, grouting strengthening index and prestress, with the aim to reveal how these factors affect the deformation of surrounding rock and the evolution of plastic zone. Then, we proposed the sensitivity evaluation index of control effect under full-length prestressed anchor grouting support. The influencing factors are divided into 3 levels: strength of surrounding rock, ground stress and design of bolt-grouting support members. Suggestions for engineering are also given according to the sensitivity level of each factor. Finally, the combined high-strength grouting bolt and high-strength hollow grouting cable are developed based on a typical roadway in weak broken strata. It can effectively enhance the self-carrying capacity of weak broken surrounding rock, give full play to the supporting potential of anchoring members, and limit the deformation and failure of roadway surrounding rock. Through the field application, the full-length prestressed bolt-grouting support is verified.
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Key words:
- full-length prestressed bolt-grouting /
- roadway /
- numerical simulation /
- sensitivity /
- control effect
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表 1 全长预应力锚注支护数值模拟对比方案
Table 1. Comparison of numerical simulation of full-length prestressed bolt-grouting support
类别 编号 地应力/MPa 原岩强度等级 支护构件长度/m 布设间距/m 注浆强化指数 预应力/kN 不同地应力 A1 5 1 2.5 0.8 1.5 60 A2 10 A3 15 A4 20 A5 25 不同原岩强度等级 B1 15 0.6 2.5 0.8 1.5 60 B2 0.8 B3 1 B4 1.2 B5 1.4 不同支护构件长度 C1 15 1 1.5 0.8 1.5 60 C2 2 C3 2.5 C4 3 C5 3.5 不同布设间距 D1 15 1 2.5 0.8(4根) 1.5 60 D2 1(4根) D3 1.2(3根) D4 1.4(3根) D5 1.6(2根) 不同注浆强化指数 E1 15 1 2.5 0.8 1 60 E2 1.25 E3 1.5 E4 1.75 E5 2 不同预应力 F1 15 1 2.5 0.8 1.5 0 F2 30 F3 60 F4 90 F5 120 表 2 不同原岩强度等级模拟方案
Table 2. Simulation schemes of different original rock strength grades
编号 原岩强度等级B 弹性模量
E/MPa黏聚力
c/MPa内摩擦角
φ/(°)不变量 B1 0.8 2 000 1.20 24.79 密度2 200 kg/m3
泊松比0.27
抗拉强度0.5 MPa
地应力15 MPaB2 0.9 2 250 1.35 27.46 B3 1.0 2 500 1.50 30.00 B4 1.1 2 750 1.65 33.15 B5 1.2 3 000 1.80 34.71 表 3 不同注浆强化指数模拟方案
Table 3. Different simulation schemes of grouting strengthening index
编号 注浆强化指数C 弹性模量E/MPa 黏聚力c/MPa 内摩擦角φ/(°) 抗拉强度/MPa 不变量 E1 1.00 2 500 1.500 30.00 0.500 密度2 200 kg/m3
泊松比0.27
地应力15 MPaE2 1.25 3 125 1.875 35.82 0.625 E3 1.50 3 750 2.250 40.90 0.750 E4 1.75 4 375 2.265 45.30 0.875 E5 2.00 5 000 3.000 49.11 1.000 -
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