吹填粉砂土固结蠕变试验及模型

通过分析法向应力、干密度、土样尺寸对吹填粉砂土蠕变特性的影响，深入研究其固结蠕变特性。与Kelvin模型相比，采用Burgers体模型能够更合理地阐释吹填粉砂土的蠕变曲线；采用FLAC^3D方法可开展吹填土蠕变过程的三维数值模拟。结果表明：吹填粉砂具有一定的蠕变特性，并可用幂函数描述应力-应变、应变-时间的关系；干密度一定时，法向应力愈大，初始应变愈大，达到稳定的时间愈长；法向应力一定时，干密度越大，初始变形越小，最终稳定所需时间越短；大尺寸试样（Ф 200.0 mm× H200.0 mm）的瞬时变形与蠕变形率要比标准尺寸（Φ 61.8 mm×H 20.0 mm）大，稳定所需时间要长；此外，Burgers体模型模拟吹填粉砂土固结蠕变变形优于广义Kelvin模型并具有可行性。

Consolidation Creep Test and Creep Model of Dredger Fill Silty Sand

The authors research the consolidation creep characteristics of dredger fill silty sand by analyzing the effect of normal stress, dry density and sample size on its creep behavior. In comparison to the Kelvin’s model, the Burgers’s model is more reasonable to interpret the creep curve of dredger fill silty sand, so the FlCD^3D method is utilized to carry out the three-dimensional numerical simulation of its consolidation creep process. The results show that dredger fill silty sand exhibits certain creep behavior and the power functions can be used to describe the stress strain relationship and strain time relationship. For the given dry density, the larger the normal stress is, the larger the initial strain is and the longer time it takes to stabilize. When normal stress is constant, the larger the dry density is, the smaller the initial deformation is and the shorter time it needs to stabilize eventually. The instantaneous deformation and creep rate of large size sample (Ф 200.0 mm×H200.0 mm) is larger than that of standard size sample (Φ61.8 mm×H20.0 mm) and the time needed for larger size sample to stabilize is longer. In addition, the Burgers’s model proved to be superior to Kelvin’s model is feasible to simulate the consolidation creep process of dredger fill silty sand. The achievements of this research can provide helpful reference for simulations of creep test and engineering practices related to dredger fill silty sand in coastal area.