Abstract:

As creep test in laboratory is usually adopted graded loading in present, it is a key problem for creep characteristics study and creep model construction to convert reasonably the creep curves by graded loading into curves by loading separately.Therefore, the influences of inear method and CHEN’s method to the characteristics of creep curves and creep parameters are compared and analysed, which are based on a series of graded loading creep tests on soft clay in Huangshi, Zhangzhou and Qingdao areas. Then some suggestions for processing method of soft clay nonlinear creep test data are put forward. The results show that creep curves can be obtained more accurately for test in loading separately by using CHEN’s method. The results are close between linear method and CHEN’s method under the lower stress level, but more different in higher stress level. The difference between two methods appears on inflection point of creep curves, and it will reduces with pressure increasing gradually. The difference of the results from two methods will get to significant for soft soil with strong creep characteristics. The difference of creep parameters is small through entire process curve is small, but is more bigger by creep curve under different pressures. The difference can also be seen in secondary consolidation coefficient, that the maximum value of Huangshi soft clay is 0.03 by linear method, but 0.07 by CHEN’s method.

Key words: soft clay, nonlinear creep, CHEN’s method, linear method