DOI: 10.15986-j.1006-7930.2020.04.008
在建商合杭客运专线新大力寺隧道下穿安徽省208省道段,隧道埋深浅,隧道围岩节理裂隙发育、稳定性差.新大力寺隧道施工过程中,S208省道正常运营; 针对隧道实际工程情况,选择更优的施工方案保证省道正常运营与施工隧道的安全是工程的重难点问题.以新大力寺隧道下穿S208公路段工程为背景,采用数值模拟方法,对比分析了二台阶法、三台阶法、六步CD法和双侧壁导坑法等4种施工方案施工引起的下穿省道路面沉降变化,新建隧道围岩和支护结构的稳定性; 考虑省道行车荷载对下穿隧道施工的影响,分析不同施工行车荷载影响下隧道施工的稳定性.基于数值模拟分析结果表明:采用六步CD法施工,下穿隧道结构的变形及结构内力控制良好,隧道施工引起的路面沉降较小; 但六步CD法施工中隧道拱顶位置衬砌内力较大,施工中采用少扰动的原则,减少对隧道拱顶围岩的影响.
Xindali-temple tunnel under construction of Shangqiu-Hangzhou passenger dedicated line runs through 208 provincial highway in Anhui province. The tunnel is buried shallow and joints and fractures in surrounding rocks are developed, resulting in poorly stability and high construction risk and difficulty. S208 provincial highway is in normal operation during the tunnel construction. According to the actual engineering geology of the tunnel, choosing a better construction plan to ensure the normal operation of the provincial highway and the safe construction of the tunnel is the primary problem to be solved. Based on the research background of Xindalis-temple tunnel passing through S208 highway section, this paper analyzes the settlement of provincial road surface caused by four construction schemes: two-step method, three-step method, six step CD method and double side wall heading method, as well as the stability of surrounding rock and supporting structure of the tunnel and the influence of highway road load on tunnel construction. Results show that:(1)The six-step CD method is more effective in controlling the displacement, deformation and internal force of the tunnel.(2)In the six-step CD construction, the internal force of the lining of the vault position is significantly higher than that of other parts, so the disturbance to the soil layer of the vault should be reduced.(3)The six-step CD method is adopted to realize the safe construction of the tunnel under normal operation conditions of highway road.
