【摘要】 采用理论分析、数值计算和现场试验等手段,研究了支护阻力对巷道围岩塑性区半径、几何分布形态与围岩连续性变形的影响,分析了围岩塑性区的形成与发展过程。研究结果表明:在现有支护技术条件下,支护阻力对围岩塑性区半径、围岩连续性变形影响十分有限;在巷道开挖卸荷初期,塑性区处于均匀扩展时段,围岩处于近似均匀协调非连续性变形,此时的支护对围岩变形限制效果并不明显;随着围岩卸荷程度的减弱,受高偏应力与采动应力的影响,塑性区进入恶性扩展时段,巷道围岩部分区域出现不均匀、不协调等连续性大变形,而锚杆(索)对这些大变形能产生较好的抑制效果。因此,对于软岩动压巷道的支护,在整体加固的同时,应对敏感部位加强支护,合理分配支护强度,支护结构具有适应性让压功能是阻止围岩不协调变形的关键。工程实践结果表明,采用"自动让压桁架锚索"为主体、"锚杆+锚索+钢筋网等支护"为辅助的综合控制技术能够保持软岩动压巷道围岩整体均匀协调变形,保障了巷道的长期使用。更多还原

【Abstract】 Impacts of supporting resistances on the plastic radius, geometric distributions and consecutive deformations in surrounding rocks are investigated by using theoretical analysis, numerical simulations and field tests. Analysis of formation and development of plastic zones are also conducted. The results show that there are limitation influence effects of supporting resistance on the radius of plastic zone and consecutive deformations of surrounding rocks. At the early stage of stress releases after tunnel excavation, plastic zones expand evenly and the deformation of surrounding rocks is characterized by appropriate evenly coordinated and non-consecutive. Limited effects of supporting on deformations of surrounding rocks are exerted. As the stress release decreases, malignant expansions of the plastic zone could induce uneven and incoordinated large deformations of surrounding rocks due to the high deviatoric stresses. Cables and bolts can be used to restrain these large deformations efficiently. Therefore, in supporting the roadways with dynamical pressure, integral consolidations combined with enhanced supporting for sensitive parts can be used to distribute supporting strengths reasonably. The supporting structure with yield and flex abilities is the key of restraining incoordinated deformations of surrounding rocks. Field engineering tests indicate that a comprehensive supporting system that the yieldable girders-cables are as the primary supporting, bolts, normal bolts and steel nets are as the supplementary supporting can restrain uneven and incoordiated deformations of roadways. The long-term use of roadways is guaranteed.更多还原