返修大断面硐室加固及数值模拟研究

Reinforcement of Repaired Large Section Chamber and Numerical Simulation

在分析硐室围岩岩性、软弱围岩流变、复杂应力环境及原支护结构失稳的基础上,结合软岩巷道围岩控制理论,提出了以全长锚固锚杆、锚索增强围岩整体性和自承载能力的主动支护,并以底板锚注加底拱返修加固.采用FLAC3D软件对原支护方案和返修加固方案进行了数值模拟,结果表明：修复加固后,最大主应力峰值外移,塑性区范围减小,围岩承载能力增强,两帮移近量41.4 mm,顶板移近量22.1 mm,底鼓量6.45 mm,支护受力合理.现场工业试验表明：经过50~90 d的矿压观测,硐室变形量小于20 mm,变形速率小于0.5 mm/d,修复加固取得了成功.

Considering the theory of roadway support in soft rock, we proposed an active support mode based on study of rheology of weak adjacent rock, complex stress environment, and destabilization of original supports. Fully grouted bolt, extension grouted cable that can strengthen self-bearing capacity and entirety are used. Original support scheme and reinforcement scheme are simulated by means of FLAC3D. Calculation results show that peaks of the maximum principal stresses move toward the surface of chamber after reinforcement, with the self-bearing capacity of rock increased and the plastic zone decreased. In addition, displacement of walls reaches 41.4 mm, that of roof, 22.1 mm, and that of heave, 6.45 mm. Further more, force of supports is in a rational scope. The field experiment shows that displacement of chamber is less than 20 mm, and convergence ratio is less than 0.5 mm/d after 50 or 90 days. So the repairing scheme of chamber is successful.