宁波软黏土流变特性试验及蠕变模型研究

EXPERIMENTAL RESEARCH ON RHEOLOGICAL BEHAVIOR OF NINGBO SOFT CLAY AND ITS CREEP MODEL

针对现场原状软黏土采用分别加载方法,开展三轴固结排水蠕变试验,研究原状土样的蠕变曲线和应力-应变等时曲线的变化规律;基于Caputo分数阶微分算子理论和Mittag-Leffler函数理论,引入Koeller弹性黏壶元件,建立了修正的Mer-at蠕变本构模型,并对试验数据进行拟合分析,结果表明:宁波地区软黏土在达到蠕变强度前,可近似看作非线性黏弹性体;相比传统Mer-at模型,修正Mer-at模型拟合精度高、误差性小,更适合表征宁波软土的蠕变特性.

Aimed of the situ undisturbed clay,the triaxial ccnsolidation drainaae creep test was carried out by using separate loading method.The veriation laws of creep curve and stress-strain tautochrone of undisturbed soils were studied.Using these experimentat data,acccrding to the modified Merchant creep ccnstitutive model,the creep curves were fitted and analyzed by introducing Koellee dashpot,which was based on the Caputo fractional differential operatos theere and Mittaa-Lefeer function theery.The resuitr showed that the Ningbo clay ccuid be regarded as a noniineas visccelastic body before reaching creep strength.The modified Merchant creep ccnstitutive model had highes fitting accusacy and small eiror in comparison with the traditionat Merchant model,so it was more suitable to characterize the ceeep chaeacteeisticsofNingbosoftcaay.