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以试刀山隧道改扩建工程为依托,选取软弱破碎带围岩段,通过三维数值模拟对隧道动态施工全过程进行弹塑性计算分析,选取该区域内某一特定横断面,主要围绕断面各监测点围岩位移随动态施工的变化特征和数值大小进行初步研究和分析。通过对计算结果分析归纳得出:从纵断面上看,对其拱顶沉降及拱底回弹影响最大的是前后6 m范围内的掌子面施工,约占总位移量的60%;对指定断面拱腰水平位移影响较大的是指定断面前后3 m范围内的掌子面施工,约占总位移量的60%~70%;从横断面上看,上台阶开挖所引起的指定断面拱顶沉降大于下部台阶开挖的影响,隧道施工对围岩塑性区的影响主要集中在洞壁外3~4m范围。此外,该数值模拟的分析结果对于该段隧道的施工监测具有一定的指导意义。
Based on the reconstruction and extension project of Testaooshan Tunnel, the surrounding rock sections of weak broken zone are selected, and the elasto-plastic calculation and analysis of the tunnel dynamic construction process is conducted by three-dimensional numerical simulation. A specific cross-section of the tunnel is selected, Point rock displacement with the dynamic construction of the changing characteristics and the size of a preliminary study and analysis. From the analysis of the calculation results, it is concluded that the most influential factor on the vault settlement and dome rebound from the longitudinal section is the construction of the face within 6 m before and after, accounting for about 60% of the total displacement; The horizontal displacement of arch and waist of designated section has a greater impact on the construction of the face within 3 m before and after the designated section, accounting for about 60% -70% of the total displacement. From the cross-section, the designation caused by the excavation on the step The settlement of the section vault is greater than that of the lower step excavation. The influence of the tunnel construction on the plastic zone of the surrounding rock mainly concentrates in the range of 3 ~ 4m outside the wall. In addition, the results of numerical simulation are of guiding significance to the construction monitoring of this section of tunnel.