盾构下穿施工对既有城市道路沉降影响研究

Wear under Shield Construction for Both City Road Subsidence Impact Study

以合肥市地铁建设四号线天水路站-翠柏路站盾构区间为工程背景,研究盾构下穿对既有城市道路造成的影响。运用Midas GTS NX建立数值分析模型,研究隧道埋深和开挖距离对道路沉降的影响。结果显示:先开挖左线时,沉降在开挖第五到第十环过程中发生突变;埋深在2D以内时,随着开挖的进行,沉降曲线从“单谷”转为“双谷”,但沉降峰值始终保持在左线隧道中心线附近;埋深超过2D,双线隧道的相互作用可以忽略,全线贯通时的沉降峰值出现在双线隧道中心线上方;埋深始终与影响范围成正比,与影响程度成反比。合理安排这两种因素能够有效控制道路沉降,保证施工安全。

Taking the shield interval from Tianshui Lu Station to Cuibai Lu Station of Hefei Metro Line 4 project as the example,the impact of shield underpassing on existing urban roads was studied.A numerical analysis model was established using Midas GTS NX to study the effects of tunnel depth and excavation distance on road settlement.The results show that when the left line is excavated first,the sudden settlement occurs during the excavation of the fifth to tenth ring;when the buried depth is within 2D,the settlement curve changes from single valley to double valleies,but the peak remains near the center line of the left tunnel;when the buried depth exceeds 2D,the interaction between the two tunnels can be ignored,and the settlement peak appears above the center line of the two tunnels when the whole line is completed.Besides,the buried depth is always proportional to the influence range and inversely proportional to the influence degree.Hence,the reasonable arrangement of these two factors can effectively control road settlement and ensure construction safety.