十字岩柱法隧道开挖地质力学模型试验研究

Geomechanical model test on the tunnel excavation with cross rock pillar method

以重庆市轨道交通三号线为工程背景,开展十字岩柱暗挖法地质力学模型试验研究,优化大断面隧道开挖工序,进行围岩岩土相似材料配比试验、模拟洞室开挖过程中锚固注浆加固作用、洞室开挖过程的围岩位移变形监测分析。试验结果表明:研制的钢结构台架可成功模拟加围压条件下的洞室开挖,可直观地观察到模型开挖时围岩的渐进破坏过程。模型试验采用的监测系统能对开挖过程中洞室围岩的位移进行实时监测,实现了开挖支护与监测记录同步进行。根据相关参数建立数值分析模型,将数值计算结果与试验实测结果进行对比分析可知:二者结果基本一致,规律大致相同,且最终位移值满足试验要求,表明模型试验取得了较为理想的效果。研究工作对实际工程施工及今后类似模型试验研究的发展具有一定指导作用。

Under the engineering background of the Chongqing rail transit line No. 3,the geomechanical model test on the cross rock pillar concealed excavation method was carried out. The excavation process of the large cross section tunnel was optimized. Various similar materials of the surrounding rock were experimentally compared,the anchoring-grouting reinforcement was simulated and the deformation of cavern excavation was monitored and analyzed. The experimental results showed that the developed structural frame successfully simulated the cavern excavation under confining pressure and that the failure process of surrounding rock was directly observed during excavation. The sensors measured the displacements in real-time in the surrounding rocks during the excavation. The simultaneous excavation supporting and deformation recording were realized. The numerical analysis model was established and the calculated results were basically identical to the test results. The final displacement value met the test requirements,indicating that the expected effect was achieved with the model test.