考虑应力路径影响的吹填土蠕变特性

Creep Characteristics Considering Stress Paths of Dredger Fill

为研究应力路径对长期变形的影响,利用WF应力路径试验仪,采用分级加载的方式,对天津滨海新区吹填土进行了减P路径(DEP)、等P加载路径(CNP)、增P加载路径(INP)3种应力路径下的蠕变试验。试验结果表明,在相同偏应力条件下,DEP、INP和CNP 3种应力路径下的蠕变应变值依次减小,蠕变稳定阶段变形速率按DEP、CNP、INP 3种应力路径的顺序依次增大;减P和等P应力路径下的蠕变试验中,孔隙水压力均为负值,且随着偏应力的增大而减小,而增P应力路径下蠕变试验中,孔隙水压力随着偏应力的增大而增大;减P和等P加载路径下长期强度高于增P应力路径下的长期强度。最后,运用二次多项式对3种路径应力应变等时曲线进行了拟合,效果较佳。

To study the influence of stress path on the long-term deformation, creep tests of dredger fill in Tianjin Binhai New Area in three different stress paths, namely decrease p paths （DEP）,constant p paths （CNP） and increase p paths （INP） respenctively, were carried out by using the WF stress paths tester and grading loading method. The results showed that under the same deviate stress conditions, the creep strain decreased in three kinds of stress paths of DEP, INP and CNP in turn, deformation rate of stable stage in the procession of creep increased according to the three kinds of stress paths of DEP, CNP, INP. The pore water pressure were negative in the procession of creep with decrease p and constant p stress paths, and decreased along with the deviate stress increase. However, in the procession of creep with increase p stress paths , the pore water pressure increased with the increase of deviator stress. The long-term strength in decrease p and constant p stress paths was higher than that in increase p stress paths. Finally, the effect is better by using quadratic polynomial to fit stress-strain isochronous curve of the three stress paths.