长期地铁振动荷载下南水北调干渠累积沉降特性研究

文章依托郑州地铁10号线下穿南水北调中线干渠工程，通过一系列动三轴试验探讨干渠附近软土层动力响应特性，基于动三轴试验及有限元分析确定Chai-Miura模型参数，研究长期地铁列车振动荷载周期作用下干渠的累积沉降规律。结果表明：郑州南水北调干渠附近软土层动应变发展趋势整体表现为“稳定型”；列车振动荷载作用初期，土体累积变形急剧增加，最大地表沉降发生在行车隧道正上方，而在长期列车振动荷载作用下，地表沉降基本趋于稳定；列车单、双线运行时的地表沉降分布规律类似，但沉降值存在差异，单线运行 $ 10^{7} $次（约为100a），地表最大累积沉降量为3.95mm，双线运行 $ 10^{7} $次后产生的累积变形量大约为5.07mm。

In view of the Zhengzhou Metro Line 10 undercrossing the main canal of the middle route of South-to-North Water Diversion Project, the dynamic response characteristics of soft soil near the main canal was discussed through a series of dynamic triaxial tests. The Chai-Miura calculation model was determined based on the dynamic triaxial tests and finite element analysis, and the accumulated settlement of the main canal induced by the long-term periodic vibration load of the subway was further studied. The results show that the dynamic strain development trend of soft soil near the main canal of the middle route of South-to-North Water Diversion Project is stable as a whole. At the initial stage of vibration load, the accumulated deformation of soil layer increased sharply, and the maximum ground settlement occurred right above the tunnel. Under the long-term vibration load, the ground settlement basically tends to be stable. The distribution of ground settlement for single-train services was similar with that of double-train services. However, the settlement value was different, the maximum accumulated ground settlement for single-train services was 3.95 mm after $ 10^{7} $ (about 100 a) load cycles; and the accumulated deformation for double-train services was about 5.07 mm after $ 10^{7} $ load cycles.