中文摘要：

汛期锚碇基础土围堰的稳定性值得深入研究。首先,基于非饱和土渗流及抗剪强度理论,推导了考虑渗流力的改进Janbu法;其次,通过土工试验及Fredlund方法,获得了土体的物理力学参数、SWCC曲线及非饱和渗透系数曲线;然后,对洪水保持过程中土围堰的稳定性进行了理论与数值分析。计算表明：洪水保持期间,浸润线未达到稳定状态,且未形成稳态渗流;洪水位和初始水位下围堰稳定性较好,水位剧降情况下围堰稳定性最差,即洪水消退过程中水位剧降是最不利工况;围堰临水侧边坡稳定系数均大于背水侧,且均随洪水浸润时间的增长而减小,临水侧边坡稳定性受浸润时间的影响比背水侧大,但短期内浸润时间的影响可忽略。

英文摘要：

The main objective of this study is on the application of the stability analysis on cofferdam of anchorage foundation. A modified Janbu method considering seepage is proposed based on the effects of shear strength and seepage for unsaturated soil. The conventional mechanical parameters,SWCC and osmotic coefficient curves can be obtained from geotechnical tests as well as the Fredlund approach. The theoretical analysis and numerical calculation for the stability of cofferdam are conducted in the case of a flood period.The key conclusions can be drawn as follows. In the flood period,a saturation line is of instability and the steady-state permeation is not attained. Under the condition of normal water level,the cofferdam is of stability but the worst operating condition occurs in the decline period. In addition,the safety factor of slopes in the side of close to water is greater than the side of away from water,and the factor decreases gradually during such a process of the increased infiltration times.