坝底水浮力对重力坝稳定性的影响分析

 着重研究一个典型的混凝土重力坝的坝底水浮力对大坝稳定性的影响，此大坝位于意大利的Cumbidanovu岛。大坝的基础由含有高度开裂的岩石所构成。首先，通过把大坝视为自由体的平衡分析法来评价大坝破坏前的最大水压力和有效排水系统对大坝稳定性的影响。然后，使用离散元方法来进一步评价开裂基岩中的水流状态，得到该水流产生的浮托力的分布，最终得到此水浮力对大坝稳定性的影响。对设计而言，上述分析考虑了岩基渗透，运用离散元方法进行模拟。研究结果表面，相比保守的平衡分析法，此模型可以得到更大的水浮力荷载。

INFLUENCES OF HYDRAULIC UPLIFT PRESSURES ON STABILITY OF GRAVITY DAM

A study of the influences of the hydraulic uplift pressures underneath the base of a typical concrete gravity dam on its stability is presented. The dam is located at Cumbidanovu(Sardegna，Italy). The foundation of the dam is made of heavily fractured rock. Firstly，analytical calculations about the equilibrium of the dam as a free body have been employed to evaluate the maximum hydraulic pressure before collapsing and to assess the impact of an effective drainage system on the stability of the dam in a simple way. Secondly，numerical analyses by the distinct element method(DEM) using the code UDEC have been carried out to evaluate the hydraulic flow taking place within the fractured rock foundation，the uplift pressure distribution generated by the calculated flow，and its influence on the stability of the dam. For design purposes，it emerges that availability of reliable data on the hydraulic permeability of rock foundations and a computationally advanced distinct element modeling might lead to the acceptance of loads significantly higher than the more conservative estimations obtained from equilibrium analyses.