郑州地铁盾构隧道下穿加油站的沉降分析

郑州地铁1号线03区间盾构施工需下穿一加油站,该加油站平行布置3个尺寸相同的埋地储油罐,总容积为150 m3,属一级加油站。3个储油罐与左线盾构隧道的竖向净距为7.0 m,水平净距为2.7 m,该加油站属Ⅰ级风险源。为保证盾构施工的安全,提出针对性的盾构掘进控制措施,采用ANSYS通用有限元软件对盾构施工下穿加油站引起的沉降进行数值模拟,计算得到的地表最大累计沉降和倾斜率均未达到监测报警值;因此,加油站在盾构施工时可以正常营业。为了保证盾构的安全推进,提出2盾构的推进间距距离、土舱压力、同步注浆压力等控制措施。盾构掘进过程中的地表和建(构)筑物的监测结果表明:地表和建(构)筑物的最大累计沉降和沉降速率均未达到监测报警值,盾构已经安全穿越加油站,文章提出的盾构掘进措施和研究方法可为类似工程提供参考。

Analysis on Settlement Induced by Shield Tunneling Underneath an Oil Station: Case Study on Zhengzhou Metro

The shield for the 3rd section of No. 1 line of Zhengzhou Metro passes underneath an oil station, which has three underground parallel oil tanks. With a total capacity of 150 m3, the oil station belongs to Grade I oil station. The vertical and horizontal distances between the left tunnel tube and the three oil tanks are 7.0 m and 2.7 m respectively. The oil station belongs to Grade I risk resources. In the paper, countermeasures are proposed for the shield tunneling so as to ensure the tunneling safety. The settlement induced by the tunneling of the shieds is simulated with ANSYS program, and the maximum cumulative ground surface settlement and inclination ratio calculated have not reached the alarm values. Therefore, the oil station can be in normal service during the shield tunneling, but field monitoring should be strengthened and emergency measures be formulated. Countermeasures in term of lagging distance between the two shields of the twin tube tunnel, the pressure in the excavation chamber and the grouting pressures are proposed so as to ensure the safe tunneling of the shields. The monitoring of the settlement of the ground surface and the buildings (structures) during the shield tunneling shows that the maximum cumulative settlement and the settlement rate have not reached the alarm values. So far the shields have already passed the oil station successfully. The paper can provide reference for similar projects in the future. 