海相结构软土的次固结研究

现有次固结计算方法没有考虑土结构性的影响，但自然沉积土大都具有结构性。海相软土一维次固结试验研究表明，对于结构性土，次固结不仅在超固结状态时与荷载有关，且在土体结构破坏的过程中也与荷载有关。当固结压力小于先期固结压力时，次固结系数随压力增长较快；当固结压力大于先期固结压力且小于结构完全屈服压力时，次固结系数随固结压力增长缓慢；当固结压力大于结构完全屈服压力时，次固结系数不随固结压力变化。次固结系数变化与否的荷载分界点不是先期固结压力，而是结构完全屈服压力。对于海相结构软土，其次固结系数变化在超固结、结构破坏、正常固结3个阶段随荷载变化的规律不同。最后，提出了考虑土结构性的一维次压缩计算方法。

Research on secondary consolidation of structural marine clays

The present calculating methods of secondary consolidation of soils do not consider the influence of structure, but most of the natural sediment soils behave the structural characteristics. The tests of marine clay performed by the authors show that secondary consolidation of structural clay relates to load not only in overconsolidation state but also in the process of structure destroying. The secondary consolidation coefficient rapidly increases with consolidation pressure when consolidation pressure is lower than the preconsolidation pressure, and slowly increases when pressure is between the preconsolidation pressure and the structure full yield stress. If the consolidation pressure is higher than the structure full yield stress, the secondary consolidation coefficient would not vary with consolidation pressure. Whether the secondary consolidation coefficient is varied with load should not be judged by preconsolidation pressure, but it should be the structure full yield stress. For marine clay, the varying process of secondary consolidation coefficient can be considered as three phases, i.e. overconsolidation, structure destroy and normal consolidation. A new calculating method is developed, which can reflect the structure behavior of soils.