Abstract: The riverside groundwater level has a unique characteristic of low for long term working conditions but extremely high during flood seasons. This characteristic should be properly taken into account for designing a safe and economical anti-float scheme. For riverside underground structures, it will be dangerous when uplift piles or uplift anchors are adopted, taking the surface elevation as the anti-floating waterproof position. On the other hand, if uplift piles or uplift anchors are designed according to 50- or 100-years recurrence intervals, it is obviously uneconomical and the cost can be extremely high. Therefore, the definition of riverside underground structures and a new anti-float method on the combination of drainage corridors and uplift piles or anchors are proposed in this paper. Besides, considering the effect of leakage recharge, a simplified analytical approach of riverside drainage corridor based on circular pond formula is also put forward and verified by the finite element method. The drainage corridors are adopted to ensure the stability of water load on the underground structure and to eliminate the extreme water load caused by high water pressures during the flood season. In contrast, the conventional measures such as uplift anchors and piles will be adopted for anti-float during non-flood period. The drainage corridors only work during the flood season with high water levels, thus it will not cause environmental problems and its durability can also be easily guaranteed. In the end of this paper, an engineering application project adopting the proposed anti-float method is introduced.

Key words: underground structures, groundwater, anti-float, seepage, drainage corridor