轴线干坞基坑灌、排水工况下坑外地下水变化规律分析

结合工程实践，采用现场测试的手段，归纳总结广州生物岛—大学城沉管隧道干坞基坑灌、排水工况下坑外地下水的变化规律：灌水加载阶段，坑外土体属“吸水”过程，排水卸载及二次开挖阶段，坑外土体属“吐水”过程，“吸水”速度大于“吐水”速度，边坡的持水能力造成边坡内外水位差局部高达4m，对边坡稳定造成威胁，但由于事先对坡角进行了处理，边坡内部渗流并未对边坡稳定造成危害，整个过程中边坡稳定性很好。

Analysis on Fluctuation Rules of Ground Water Levels outside Axial Dry Docks during Water Filling Period and Water Discharging Period

The fluctuation rules of the ground water levels outside the foundation pit during water filling period and water discharging period are summarized on basis of site measurements, with the immersed tunnel from Shengwudao Island to University Town as an example. During the water filling period, the soil outside the foundation pit is in a water-absorbing process; during the water discharging and secondary excavation period, the soil outside the foundation pit is in a water-releasing process; the water absorbing rate is higher than the water releasing rate; due to the water bearing capacity of the side slope, the difference between the water level inside the foundation pit and that outside the foundation pit at local positions reaches 4m, which severely jeopardizes the stability of the side slope. Due to the treatment of the slope foot in advance, the water seepage inside the side slope has not jeopardized the stability of the side slope. In the whole course, the side slope has good stability.