软土蠕变数据处理方法的对比分析

Comparative Analysis of Soft Clay Creep Data Processing Method

室内蠕变试验多采用分级加载的方式,如何使分级加载蠕变试验结果转换成分别加载的曲线更趋合理,是研究蠕变特性和建立蠕变模型的关键问题。通过对黄石、漳州、青岛地区软土采用分级加载方式的多种蠕变试验,根据线性法与陈氏法处理蠕变试验数据,对比2种方法对蠕变曲线和蠕变参数的影响,进而为软土非线性蠕变试验数据处理方法提出合理性建议。结果表明:利用陈氏法可准确地获得分别加载下的各级压力的蠕变曲线。低应力水平下,线性法与陈氏法结果接近;高应力水平下,2种方法结果差距较大。差别较大出现在蠕变曲线弯点处,随着压力的增大,差距逐渐减小。蠕变性较强的软土,采用2种方法处理的蠕变结果会相差悬殊。通过试验全过程曲线得到的蠕变参数相差较小,而通过不同压力下蠕变曲线得到的蠕变参数相差较大,如采用线性法得到黄石软土次固结系数Ca最大值为0.03;采用陈氏法得到Ca最大值为0.07。

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.