中文摘要：

为探讨钢板桩围堰体系工作特性，通过建立双排钢板桩围堰体系弹塑性有限元数值模型，采用基于Molar—Coulomb破坏准则的理想弹塑性本构模型考虑土石物的弹塑性性质，采用罚函数接触算法描述界面接触特性，针对不同水位下钢板桩围堰在加载过程中呈现的受力变形特征进行了分析与讨论。计算分析表明：在高水位时外侧钢板桩承受被动土压力，而在低水位时外侧钢板桩承受主动土压力。在极端高、低水位情况下，围堰土石体系均在拉杆内侧端部附近区域存在明显的塑性区，在极端低水位下拉杆外侧端部土石体系附近区域也存在明显塑性区。围堰外水位越低，围堰外侧钢板桩承受的主动土压力越大，外侧钢板桩的正向侧向变形亦越明显，拉杆和钢板桩强度特性发挥的越充分。因此，随着围堰外水位标高增加，拉杆截面正应力变化率呈现逐渐衰减变化特征。

英文摘要：

Aiming at discussing the working performance of cofferdam system with steel sheet piles, nonlinear numerical computation is conducted in the present work by developing elasto-plastic FE model in plane stress state, employing Mohr-Coulomb yield criterion to describe the elaso-plasticity of subsoil and Coulomb contact pair theory with penalty algorithm to simulate the discontinuous contact behavior between foundation and soil, as well as using infinite element in model boundaries to avoid static boundary effect. The numerical results show that the outer sheet pile bears passive earth pressure at higher water level and active earth pressure at lower level. Plastic zone exists in the earth and stone of cofferdam system near the inner end of tensional rod at both maximum and minimum water levels. Differently, plastic zone only lies near the outer end of tensional rod at minimum water level in the earth and stone of cofferdam system. The lower water height is, the more active pressure and positive lateral deformation of outer steel sheet pile are. Due to the augment of exerting sufficiency with the increase of water height level for the strength of tensional rod, the variation ratios of normal stress of tensional rod section display decreasing characteristics.