对汕头东部入海口的吹填软土进行了一维次固结试验和三轴固结不排水蠕变试验，分析了这两种机制不同的蠕变特性。一维试验结果表明，软黏土的应力-应变关系呈现出明显的非线性特征，且当土体处于超固结状态时，其主固结和次固结变形相对于正常固结状态会变小，预压可以提高土体的结构屈服强度。在三轴固结不排水蠕变试验中，孔压会随时间一直发展，即有效应力不断减小。当偏应力较小时，土体的变形最终会趋于稳定，应变率也随时间一直减弱；而当荷载增加到临界值时，土体的变形会随时间快速发展，发生加速蠕变破坏。引入分数阶导数的概念，建立了含分数阶导数的Merchant模型，对两种试验数据分别进行拟合并给出了参数范围，结果表明：与经典的Merchant模型相比，分数阶导数Merchant模型能更好地描述软土的蠕变变形，而且模型简单、参数少，能很好地应用到实际工程中。

A series of 1D secondary consolidation tests and undrained triaxial creep tests are conducted to investigate the creep characteristics of soft dredger fill in the estuary of eastern Shantou. In 1D secondary consolidation tests，the stress-stain relationship of the soft soil shows significant nonlinear characteristics. The deformations of primary compression and secondary compression in overconsolidation state is smaller than normal consolidation case; and preloading can increase the yield strength. Pore pressure develops over time in the undrained triaxial creep tests, i.e., effective stress decreases with time. When the deviatoric stress is smaller, the deformation of soil tends to be stable, and the strain rate decreases with time; however, once the deviatoric stess reaches the critical value, the deformation develops with time rapidly, and the soil sample is damaged due to the accelerated creep. The concept of fractional order derivative is introduced to establish the fractional derivative Merchant model; and the ranges of parameters are determined. By comparison with the fitting results of traditional Merchant model, it is found that the fractional Merchant model can simulate the creep deformation better. The fractional Merchant model has a simple form and a few parameters, which can be well applied to the practical engineering.